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What is this summary about? This is a summary of an article about part of a clinical study for the BNT162b2 COVID-19 vaccine, also called the Pfizer-BioNTech vaccine. The article was published in the New England Journal of Medicine in May 2021. This summary describes how the vaccine worked in participants 12- to 15-years old. The part of the study described in the article is ongoing and expected to finish March 2023. This means that the final results may be different from the results included in this summary. What happened in this study? The part of the study described in this summary included participants 12- to 15-years old who had no serious health issues. The BNT162b2 vaccine had already been studied in participants 16 years of age or older. In this part of the study, the researchers wanted to find out: How effective and safe the vaccine was in participants 12- to 15-years old. What the immune response to the vaccine and the vaccine safety were like in 12- to 15-year-olds compared with 16- to 25-year-olds. How well the vaccine prevented SARS-CoV-2 infections in participants who received the vaccine compared to those who did not. This is also called efficacy of the BNT162b2 vaccine Half of the participants in this study received 2 injections of the BNT162b2 vaccine and half received 2 injections of a placebo in a muscle of the upper arm. The placebo looked like the BNT162b2 vaccine but did not have any active vaccine in it. What were the results? BNT162b2 had a favorable safety profile. The most common reactions were pain at the injection site, fatigue, and headache. None of the participants had serious reactions to the vaccine. The 12- to 15-year-old participants' immune system responses to the BNT162b2 vaccine were as good as or stronger than the 16- to 25-year-old participants' immune responses. The participants who received the BNT162b2 vaccine were less likely to get COVID-19 compared with the participants who got the placebo. Clinical Trial Registration: NCT04368728 ( ClinicalTrials.gov )

What is this summary about? This is a summary of an article about part of a clinical study for the BNT162b2 COVID-19 vaccine, also called the Pfizer-BioNTech vaccine. The article was published in the New England Journal of Medicine in September 2021. The part of the study described in the article began in July 2020 and is ongoing. This means that the final results may be different from the results included in this summary. What happened in this study? The participants in this study received 2 injections of either the BNT162b2 vaccine or a placebo, 21 days apart. The placebo looked like the BNT162b2 vaccine but had no active vaccine in it. None of the trial participants or study teams knew who received vaccine or placebo. What were the results? Most of the reactions to the injections were mild or moderate and lasted for a short period of time. The most common reactions were pain at the injection site, extreme tiredness (fatigue), and headache. These reactions usually happened in the first 7 days after receiving a vaccine dose. A small number of participants had severe reactions to the vaccine. Compared to participants who received the placebo, participants who received the BNT162b2 vaccine were much less likely to become ill if they were infected with the virus that causes COVID-19. The vaccine also had very good efficacy at preventing severe COVID-19. Participants in South Africa who received the BNT162b2 vaccine were less likely to become ill after infection with the beta variant of the virus compared to participants who received the placebo. The beta variant was very common in South Africa when the study was taking place. Clinical Trial Registration: NCT04368728 ( ClinicalTrials.gov )

Respiratory syncytial virus (RSV) is the leading, global cause of serious respiratory disease in infants and is an important cause of respiratory illness in older adults. No RSV vaccine is currently available. The RSV fusion (F) glycoprotein is a key antigen for vaccine development, and its prefusion conformation is the target of the most potent neutralizing antibodies. Here, we describe a computational and experimental strategy for designing immunogens that enhance the conformational stability and immunogenicity of RSV prefusion F. We obtained an optimized vaccine antigen after screening nearly 400 engineered F constructs. Through in vitro and in vivo characterization studies, we identified F constructs that are more stable in the prefusion conformation and elicit ~10-fold higher serum-neutralizing titers in cotton rats than DS-Cav1. The stabilizing mutations of the lead construct (847) were introduced onto F glycoprotein backbones of strains representing the dominant circulating genotypes of the two major RSV subgroups, A and B. Immunization of cotton rats with a bivalent vaccine formulation of these antigens conferred complete protection against RSV challenge, with no evidence of disease enhancement. The resulting bivalent RSV prefusion F investigational vaccine has recently been shown to be efficacious against RSV disease in two pivotal phase 3 efficacy trials, one for passive protection of infants by immunization of pregnant women and the second for active protection of older adults by direct immunization.

Background Respiratory syncytial virus (RSV) is an important cause of disease in older adults. We evaluated the safety and immunogenicity of a stabilized RSV prefusion F subunit (RSVpreF) vaccine candidate with/without adjuvant in adults aged 65–85 years. Methods Primary cohort participants were equally randomized to 1 of 7 RSVpreF formulations: 60 µg with either Al(OH)3 or CpG/Al(OH)3, 120 µg with either Al(OH)3 or CpG/Al(OH)3, 240 µg with either Al(OH)3 or CpG/Al(OH)3, 240 µg unadjuvanted, or placebo, administered concomitantly with high-dose seasonal inactivated influenza vaccine (SIIV). Participants in the month 0,2 cohort were randomized to RSVpreF 240 µg with CpG/Al(OH)3 or placebo, administered at months 0 and 2. Results All RSVpreF vaccine candidates elicited robust and persistent serum neutralizing responses when administered alone or with SIIV. There was no notable difference in neutralizing response between the formulations, including those containing CpG. In the month 0,2 cohort, there was no booster effect of dose 2. SIIV responses were similar or slightly lower with concomitant administration of RSVpreF. Most systemic and local reactions were mild and more frequent after RSVpreF than placebo. Conclusions RSVpreF formulations were well tolerated and elicited robust neutralizing responses in older adults; however, CpG/Al(OH)3 did not further enhance responses. Clinical Trials Registration. NCT03572062.

Respiratory syncytial virus (RSV), a major cause of illness and death in infants worldwide, could be prevented by vaccination during pregnancy. The efficacy, immunogenicity, and safety of a bivalent RSV prefusion F protein-based (RSVpreF) vaccine in pregnant women and their infants are uncertain.In a phase 2b trial, we randomly assigned pregnant women, at 24 through 36 weeks' gestation, to receive either 120 or 240 μg of RSVpreF vaccine (with or without aluminum hydroxide) or placebo. The trial included safety end points and immunogenicity end points that, in this interim analysis, included 50% titers of RSV A, B, and combined A/B neutralizing antibodies in maternal serum at delivery and in umbilical-cord blood, as well as maternal-to-infant transplacental transfer ratios.This planned interim analysis included 406 women and 403 infants; 327 women (80.5%) received RSVpreF vaccine. Most postvaccination reactions were mild to moderate; the incidence of local reactions was higher among women who received RSVpreF vaccine containing aluminum hydroxide than among those who received RSVpreF vaccine without aluminum hydroxide. The incidences of adverse events in the women and infants were similar in the vaccine and placebo groups; the type and frequency of these events were consistent with the background incidences among pregnant women and infants. The geometric mean ratios of 50% neutralizing titers between the infants of vaccine recipients and those of placebo recipients ranged from 9.7 to 11.7 among those with RSV A neutralizing antibodies and from 13.6 to 16.8 among those with RSV B neutralizing antibodies. Transplacental neutralizing antibody transfer ratios ranged from 1.41 to 2.10 and were higher with nonaluminum formulations than with aluminum formulations. Across the range of assessed gestational ages, infants of women who were immunized had similar titers in umbilical-cord blood and similar transplacental transfer ratios.RSVpreF vaccine elicited neutralizing antibody responses with efficient transplacental transfer and without evident safety concerns. (Funded by Pfizer; ClinicalTrials.gov number, NCT04032093.).

Coronavirus disease 2019 (COVID-19) in humans has a wide range of presentations, ranging from asymptomatic or mild symptoms to severe illness. Suitable animal models mimicking varying degrees of clinical disease manifestations could expedite development of therapeutics and vaccines for COVID-19. Here we demonstrate that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection resulted in subclinical disease in rhesus macaques with mild pneumonia and clinical disease in Syrian hamsters with severe pneumonia. SARS-CoV-2 infection was confirmed by formalin-fixed, paraffin-embedded (FFPE) polymerase chain reaction (PCR), immunohistochemistry, or in situ hybridization. Replicating virus in the lungs was identified using in situ hybridization or virus plaque forming assays. Viral encephalitis, reported in some COVID-19 patients, was identified in one macaque and was confirmed with immunohistochemistry. There was no evidence of encephalitis in hamsters. Severity and distribution of lung inflammation were substantially more in hamsters compared with macaques and exhibited vascular changes and virus-induced cytopathic changes as seen in COVID-19 patients. Neither the hamster nor macaque models demonstrated evidence for multisystemic inflammatory syndrome (MIS). Data presented here demonstrate that macaques may be appropriate for mechanistic studies of mild asymptomatic COVID-19 pneumonia and COVID-19-associated encephalitis, whereas Syrian hamsters may be more suited to study severe COVID-19 pneumonia.

Background Respiratory syncytial virus (RSV) causes substantial morbidity and mortality in older adults and adults with comorbidities. An effective vaccine is needed. An investigational bivalent prefusion F vaccine (RSVpreF) was assessed in healthy adults. Methods This phase 1/2 study randomized adults 18–85 years old to receive placebo or 60, 120, or 240 µg RSVpreF (with or without aluminum hydroxide) alone or concomitantly with seasonal inactivated influenza vaccine (SIIV). Safety and immunogenicity were assessed. Results In older adults, reactogenicity events were predominantly mild or moderate among RSVpreF recipients; adverse events through 1 month postvaccination were similar across formulations. Coadministration with SIIV did not appear to affect safety among younger or older adults. All RSVpreF formulations with or without concomitant SIIV elicited robust RSV serum-neutralizing responses in adults aged 50–85 years 1 month postvaccination. Neutralizing titers 1 and 12 months postvaccination were 6.9–14.9 and 2.9–4.5 times, respectively, those before vaccination. SIIV immune responses trended lower when coadministered with RSVpreF. Conclusions RSVpreF formulations administered alone or with SIIV were well tolerated and highly immunogenic in older adults, supporting the potential for RSVpreF to protect older adults from RSV disease. Clinical Trials Registration NCT03529773.

Background Protection against human respiratory syncytial virus (RSV) remains an unmet need potentially addressable by maternal immunization. This phase 1/2 study evaluated a bivalent prefusion F vaccine (RSVpreF) with antigens from RSV subgroups A and B. Methods Adults 18–49 years old (N = 618) were randomized to receive placebo or 60, 120, or 240 µg RSVpreF with or without Al(OH)3. Safety and immunogenicity were evaluated. Results RSVpreF recipients more frequently reported local reactions and systemic events than placebo recipients; these were mostly mild or moderate. No vaccine-related serious adverse events occurred through 12 months postvaccination. All RSVpreF formulations induced 1-month postvaccination virus-neutralizing titers higher than those associated with protection of high-risk infants by palivizumab, the only prophylactic currently available for RSV. Geometric mean fold rises (GMFRs) across RSVpreF doses/formulations were 10.6–16.9 for RSV A and 10.3–19.8 for RSV B at 1 month postvaccination, greater than those historically elicited by postfusion F vaccines. GMFRs were 3.9–5.2 and 3.7–5.1, respectively, at 12 months postvaccination. Conclusions RSVpreF formulations were safe, well tolerated, and induced robust neutralizing responses in adults. These findings support development of RSVpreF, which is being evaluated in a pivotal phase 3 study for maternal immunization. Clinical Trials Registration NCT03529773.

Background Respiratory syncytial virus (RSV) is an important cause of disease in older adults and is associated with high morbidity and mortality, especially in those with high-risk conditions. Illness can vary from mild upper respiratory tract symptoms to more severe lower respiratory tract disease. After over 50 years of research, there is now hope for an RSV vaccine for any population, including older adults. An investigational bivalent RSV A and B, stabilized RSV prefusion F subunit vaccine (RSVpreF) was assessed successfully in a pivotal phase 3 efficacy study in older adults. (NCT05035212). Methods The primary efficacy objective of this Phase 3, global, multicenter, randomized, double-blinded, placebo-controlled study was to evaluate the prevention of RSV associated lower respiratory tract illness (LRTI-RSV) in up to 40,000 adults ≥60 years of age during the first winter season (September 2021-June 2022). Two primary endpoints were tested sequentially – LRTI-RSV with ≥2 and ≥3 symptoms. A pre-planned efficacy interim analysis (IA) was to be conducted by an external Data Monitoring Committee (DMC) upon accrual of at least 29 cases of LRTI-RSV with ≥2 symptoms. With efficacy demonstrated for cases with ≥2 symptoms and sufficient cases with ≥ 3 symptoms accrued, an efficacy analysis of cases with ≥ 3 symptoms was to be conducted. The ongoing study is collecting additional safety and descriptive efficacy data. Results At the time of the IA, approximately 34,000 participants received either RSVpreF 120 µg (60 µg each of RSVpreF from RSV A and RSV B) or placebo (1:1 randomization). Forty-four LRTI-RSV cases with ≥2 symptoms were accrued with 11 cases in the RSVpreF group and 33 cases in the placebo group corresponding to a VE of 66.7% (96.66% CI: 28.8%, 85.8%). Sixteen LRTI-RSV cases with ≥3 symptoms were accrued with 2 cases in the RSVpreF group and 14 cases in the placebo group corresponding to a VE of 85.7% (96.66% CI: 32.0%, 98.7%). The investigational vaccine was well-tolerated with no safety concerns. Conclusion Despite unpredictable RSV activity due to the COVID-19 pandemic, the primary objective of the study was met demonstrating that RSVpreF had a favorable safety profile and was highly efficacious in preventing LRTI-RSV with ≥2 symptoms and ≥3 symptoms in older adults 60 years and older. Disclosures Edward E. Walsh, MD, Janssen: Honoraria|Merck: Grant/Research Support|Pfizer: Grant/Research Support Fernando Polack, MD, I-trials: Ownership Interest|Pfizer: Grant/Research Support Agnieszka Zareba, MD PhD, Pfizer: employee of Pfizer Ann R. Falsey, MD, BioFire Diagnostics: Grant/Research Support|Janssen: Grant/Research Support|Merck Sharp & Dohme: Grant/Research Support|Novavax: Advisor/Consultant|Pfizer: Grant/Research Support Gonzalo Perez Marc, MD, I-trials: Board Member|I-trials: Ownership Interest|Pfizer: Grant/Research Support Qin Jiang, PhD, Pfizer: employee of Pfizer Kathy Schneider, PhD, Pfizer: employee of Pfizer David Cooper, PhD, Pfizer: employee of Pfizer Maria Maddalena Lino, PhD, Pfizer: employee of Pfizer Annaliesa S. Anderson, PhD, Pfizer: employee of Pfizer|Pfizer Inc: Employee|Pfizer Inc: Stocks/Bonds Katherin U Jensen, PhD, Pfizer: employee of Pfizer Kena A. Swanson, Ph.D., Pfizer: employee of Pfizer Alejandra C. Gurtman, M.D., Pfizer: employee of Pfizer William C. Gruber, MD, Pfizer Inc: Employee|Pfizer Inc: Stocks/Bonds Beate Schmoele-Thoma, MD, Pfizer: employee of Pfizer.

Background Respiratory syncytial virus (RSV) is a major cause of infant morbidity and mortality worldwide and could be preventable by vaccination in pregnancy. Methods We conducted a randomized, placebo-controlled phase 2b trial evaluating safety, immunogenicity, and potential efficacy of a bivalent RSV prefusion F vaccine (RSVpreF) in pregnant women and their infants. Participants were randomized between 24- and 36-weeks’ gestation to receive 120 or 240 µg RSVpreF, with or without aluminum hydroxide, or placebo. Results This final analysis includes 579 women and 572 infants in 4 countries (Argentina, Chile, South Africa, and the US); 462 (79.8%) women received RSVpreF. Postvaccination reactions, most commonly injection site pain, fatigue, and myalgia, were generally mild-to-moderate. Adverse events (AEs) in the month following vaccination (maternal) or birth (infant) were mostly anticipated events in pregnancy and the neonatal period, respectively, and were similar between vaccine and placebo groups. No AEs were considered related to vaccination. For all RSVpreF groups, 50% neutralizing titers for both RSV-A and RSV-B rose sharply by 2 weeks after vaccination. At delivery occurring a mean of ∼8 weeks later, geometric mean titer (GMT) ratios for combined RSV-A/B between vaccine and placebo recipients’ infants were 10.9 to 13.6. Transplacental transfer ratios (all groups) were 1.39 to 1.83. Infant GMTs were higher in infants whose mothers had received RSVpreF versus placebo through 6 months of life; the estimated half-life of infant combined 50% RSV-A/B neutralizing titers was 41 days. Infants of women immunized across the range of assessed gestational ages had similar cord blood titers and transplacental transfer ratios. Observed efficacy (95% CI) against medically attended and severe medically attended infant RSV lower respiratory tract illness (LRTI) through 180 days in an exploratory analysis was 84.7% (21.5%, 97.6%) and 91.5% (-5.6%, 99.8%), respectively. Conclusion RSVpreF was well-tolerated in pregnant women, elicited robust neutralizing responses with efficient transplacental transfer, and has the potential to prevent infant RSV LRTI. Disclosures Eric A. F. Simões, MD, M.B., B.S., DCH, Abbvie: DSMB|Astra Zeneca: Grant/Research Support|Bill and Melinda Gates Foundation: Grant/Research Support|Bill and Melinda Gates Foundation: DSMB|GSK Inc.: DSMB|Johnson and Johnson: Grant/Research Support|Merck Inc: Advisor/Consultant|Merck Inc: Grant/Research Support|Nivavax: Grant/Research Support|Pfizer Inc: Advisor/Consultant|Pfizer Inc: Grant/Research Support|Regeneron: Grant/Research Support|Sanofi Pasteur: Advisor/Consultant Shabir A. Madhi, MBBCh, FCPaeds, MMed, PhD, AstraZeneca: Funding to institution for conduct of study Kimberly J. Center, M.D., Pfizer: Employee|Pfizer: Stocks/Bonds Jose M. Novoa Pizarro, MD, AstraZeneca: Grant/Research Support|Medimmune: Grant/Research Support|MSD: Grant/Research Support|Pfizer: Grant/Research Support|Regeneron: Grant/Research Support Kena A. Swanson, Ph.D., Pfizer: employee of Pfizer David Radley, MS, Pfizer: Employee|Pfizer: Stocks/Bonds Stephanie B. McGrory, B.S.N., Pfizer: Employee|Pfizer: Stocks/Bonds Emily A. Gomme, Ph.D., Pfizer: Stocks/Bonds Daniel A. Scott, MD, Pfizer: Employee|Pfizer: Stocks/Bonds Kathrin U. Jansen, PhD, Pfizer Inc: Employee|Pfizer Inc: Stocks/Bonds William C. Gruber, MD, Pfizer Inc: Employee|Pfizer Inc: Stocks/Bonds Alejandra C. Gurtman, M.D., Pfizer: employee of Pfizer.

Background BNT162b2 is a lipid nanoparticle–formulated, nucleoside-modified RNA vaccine encoding a prefusion-stabilized, membrane-anchored severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) full-length spike protein. BNT162b2 is highly efficacious against coronavirus disease 2019 (Covid-19) and is currently approved, conditionally approved, or authorized for emergency use worldwide. At the time of initial authorization, data beyond 2 months after vaccination were unavailable. Methods In an ongoing, placebo-controlled, observer-blinded, multinational, pivotal efficacy trial, we randomly assigned 44,165 participants 16 years of age or older and 2264 participants 12 to 15 years of age to receive two 30-μg doses, at 21 days apart, of BNT162b2 or placebo. The trial end points were vaccine efficacy against laboratory-confirmed Covid-19 and safety, which were both evaluated through 6 months after vaccination. Results BNT162b2 continued to be safe and have an acceptable adverse-event profile. Few participants had adverse events leading to withdrawal from the trial. Vaccine efficacy against Covid-19 was 91.3% (95% confidence interval [CI], 89.0 to 93.2) through 6 months of follow-up among the participants without evidence of previous SARS-CoV-2 infection who could be evaluated. There was a gradual decline in vaccine efficacy. Vaccine efficacy of 86 to 100% was seen across countries and in populations with diverse ages, sexes, race or ethnic groups, and risk factors for Covid-19 among participants without evidence of previous infection with SARS-CoV-2. Vaccine efficacy against severe disease was 96.7% (95% CI, 80.3 to 99.9). In South Africa, where the SARS-CoV-2 variant of concern B.1.351 (or beta) was predominant, a vaccine efficacy of 100% (95% CI, 53.5 to 100) was observed. Conclusions Through 6 months of follow-up and despite a gradual decline in vaccine efficacy, BNT162b2 had a favorable safety profile and was highly efficacious in preventing Covid-19. (Funded by BioNTech and Pfizer; ClinicalTrials.gov number, NCT04368728.)

The BNT162b2 bivalent BA.4/5 COVID-19 vaccine has been authorized to mitigate COVID-19 due to current Omicron and potentially future variants. New sublineages of SARS-CoV-2 Omicron continue to emerge and have acquired additional mutations, particularly in the spike protein, that may lead to improved viral fitness and immune evasion. The present study characterized neutralization activities against new Omicron sublineages BA.4.6, BA.2.75.2, BQ.1.1, and XBB.1 after a 4thdose (following three doses of BNT162b2) of either the original monovalent BNT162b2 or the bivalent BA.4/5 booster in individuals >55 years of age. For all participants, the 4thdose of monovalent BNT162b2 vaccine induced a 3.0×, 2.9×, 2.3×, 2.1×, 1.8×, and 1.5× geometric mean neutralizing titer fold rise (GMFR) against USA/WA1-2020 (a strain isolated in January 2020), BA.4/5, BA.4.6, BA.2.75.2, BQ.1.1, and XBB.1, respectively; the bivalent vaccine induced 5.8×, 13.0×, 11.1×, 6.7×, 8.7×, and 4.8× GMFRs. For individuals without SARS-CoV-2 infection history, BNT162b2 monovalent induced 4.4×, 3.0×, 2.5×, 2.0×, 1.5×, and 1.3× GMFRs, respectively; the bivalent vaccine induced 9.9×, 26.4×, 22.2×, 8.4×, 12.6×, and 4.7× GMFRs. These data suggest the bivalent BA.4/5 vaccine is more immunogenic than the original BNT162b2 monovalent vaccine against circulating Omicron sublineages, including BQ.1.1 that is becoming prevalent globally.

The SARS-CoV-2 Omicron variant and its sublineages show pronounced viral escape from neutralizing antibodies elicited by vaccination or prior SARS-CoV-2 variant infection owing to over 30-amino acid alterations within the spike (S) glycoprotein. Breakthrough infection of vaccinated individuals with Omicron sublineages BA.1 and BA.2 is associated with distinct patterns of cross-neutralizing activity against SARS-CoV-2 variants of concern (VOCs). In continuation of our previous work, we characterized the effect of Omicron BA.4/BA.5 S glycoprotein exposure on the neutralizing antibody response upon breakthrough infection in vaccinated individuals and upon variant-adapted booster vaccination in mice. We found that immune sera from triple mRNA-vaccinated individuals with subsequent breakthrough infection during the Omicron BA.4/BA.5 wave showed cross-neutralizing activity against previous Omicron variants BA.1, BA.2, BA.2.12.1, and BA.4/BA.5 itself. Administration of a prototypic BA.4/BA.5-adapted mRNA booster vaccine to mice after SARS-CoV-2 wild-type strain-based primary immunization is associated with broader cross-neutralizing activity than a BA.1-adapted booster. Whereas the Omicron BA.1-adapted mRNA vaccine in a bivalent format (wild-type + BA.1) broadens cross-neutralizing activity relative to the BA.1 monovalent booster, cross-neutralization of BA.2 and descendants is more effective in mice boosted with a bivalent wild-type + BA.4/BA.5 vaccine. In naïve mice, primary immunization with the bivalent wild-type + Omicron BA.4/BA.5 vaccine induces strong cross-neutralizing activity against Omicron VOCs and previous variants. These findings suggest that, when administered as boosters, mono- and bivalent Omicron BA.4/BA.5-adapted vaccines enhance neutralization breadth and that the bivalent version also has the potential to confer protection to individuals with no preexisting immunity against SARS-CoV-2.

The SARS-CoV-2 Omicron variant and its sublineages show pronounced viral escape from neutralizing antibodies elicited by vaccination or prior SARS-CoV-2 variant infection owing to over 30 amino acid alterations within the spike (S) glycoprotein. We and others have recently reported that breakthrough infection of vaccinated individuals with Omicron sublineages BA.1 and BA.2 are associated with distinct patterns of cross-neutralizing activity against SARS-CoV-2 variants of concern (VOCs). BA.2 breakthrough infection mediated overall stronger cross-neutralization of BA.2 and its descendants (BA.2.12.1, BA.4, and BA.5) compared to BA.1 breakthrough infection. Here we characterized the effect of Omicron BA.4/BA.5 S glycoprotein exposure on the magnitude and breadth of the neutralizing antibody response upon breakthrough infection in vaccinated individuals and in mice upon booster vaccination. We show that immune sera from triple mRNA-vaccinated individuals with subsequent Omicron BA.4/BA.5 breakthrough infection display broad and robust neutralizing activity against Omicron BA.1, BA.2, BA.2.12.1, and BA.4/BA.5. Administration of a prototypic BA.4/BA.5-adapted mRNA booster vaccine to mice following SARS-CoV-2 wild-type strain-based primary immunization is associated with similarly broad neutralizing activity. Immunization of naïve mice with a bivalent mRNA vaccine (wild-type + Omicron BA.4/BA.5) induces strong and broad neutralizing activity against Omicron VOCs and previous variants. These findings suggest that when administered as boosters, mono- and bivalent Omicron BA.4/BA.5-adapted vaccines may enhance neutralization breadth, and in a bivalent format may also have the potential to confer protection to individuals with no pre-existing immunity against SARS-CoV-2.

Although human respiratory syncytial virus (RSV) is an important cause of illness and death in older adults, no RSV vaccine has been licensed.In a phase 2a study, we randomly assigned healthy adults (18 to 50 years of age), in a 1:1 ratio, to receive a single intramuscular injection of either bivalent prefusion F (RSVpreF) vaccine or placebo. Approximately 28 days after injection, participants were inoculated intranasally with the RSV A Memphis 37b challenge virus and observed for 12 days. The per-protocol prespecified primary end points were the following: reverse-transcriptase-quantitative polymerase-chain-reaction (RT-qPCR)-confirmed detectable RSV infection on at least 2 consecutive days with at least one clinical symptom of any grade from two categories or at least one grade 2 symptom from any category, the total symptom score from day 1 to discharge, and the area under the curve (AUC) for the RSV viral load in nasal-wash samples measured by means of RT-qPCR from day 2 after challenge to discharge. In addition, we assessed immunogenicity and safety.After participants were inoculated with the challenge virus, vaccine efficacy of 86.7% (95% CI, 53.8 to 96.5) was observed for symptomatic RSV infection confirmed by any detectable viral RNA on at least 2 consecutive days. The median AUC for the RSV viral load (hours × logRSVpreF vaccine was effective against symptomatic RSV infection and viral shedding. No evident safety concerns were identified. These findings provide support for further evaluation of RSVpreF vaccine in a phase 3 efficacy study. (Funded by Pfizer; EudraCT number, 2020-003887-21; ClinicalTrials.gov number, NCT04785612.).

Distinct SARS-CoV-2 Omicron sublineages have evolved showing increased fitness and immune evasion than the original Omicron variant BA.1. Here we report the neutralization activity of sera from BNT162b2 vaccinated individuals or unimmunized Omicron BA.1-infected individuals against Omicron sublineages and “Deltacron” variant (XD). BNT162b2 post-dose 3 immune sera neutralized USA-WA1/2020, Omicron BA.1-, BA.2-, BA.2.12.1-, BA.3-, BA.4/5-, and XD-spike SARS-CoV-2s with geometric mean titers (GMTs) of 1335, 393, 298, 315, 216, 103, and 301, respectively; thus, BA.4/5 SARS-CoV-2 spike variant showed the highest propensity to evade vaccine neutralization compared to the original Omicron variants BA.1. BA.1-convalescent sera neutralized USA-WA1/2020, BA.1-, BA.2-, BA.2.12.1-, BA.3-, BA.4/5-, and Deltacron-spike SARS-CoV-2s with GMTs of 15, 430, 110, 109, 102, 25, and 284, respectively. The low neutralization titers of vaccinated sera or convalescent sera from BA. 1 infected individuals against the emerging and rapidly spreading Omicron BA.4/5 variants provide important results for consideration in the selection of an updated vaccine in the current Omicron wave.

Initial COVID-19 vaccine candidates were based on the original sequence of SARS-CoV-2. However, the virus has since accumulated mutations, among which the spike D614G is dominant in circulating virus, raising questions about potential virus escape from vaccine-elicited immunity. Here, we report that the D614G mutation modestly reduced (1.7–2.4-fold) SARS-CoV-2 neutralization by BNT162b2 vaccine-elicited mouse, rhesus, and human sera, concurring with the 95% vaccine efficacy observed in clinical trial.

A safe and effective vaccine against COVID-19 is urgently needed in quantities that are sufficient to immunize large populations. Here we report the preclinical development of two vaccine candidates (BNT162b1 and BNT162b2) that contain nucleoside-modified messenger RNA that encodes immunogens derived from the spike glycoprotein (S) of SARS-CoV-2, formulated in lipid nanoparticles. BNT162b1 encodes a soluble, secreted trimerized receptor-binding domain (known as the RBD–foldon). BNT162b2 encodes the full-length transmembrane S glycoprotein, locked in its prefusion conformation by the substitution of two residues with proline (S(K986P/V987P); hereafter, S(P2) (also known as P2 S)). The flexibly tethered RBDs of the RBD–foldon bind to human ACE2 with high avidity. Approximately 20% of the S(P2) trimers are in the two-RBD ‘down’, one-RBD ‘up’ state. In mice, one intramuscular dose of either candidate vaccine elicits a dose-dependent antibody response with high virus-entry inhibition titres and strong T-helper-1 CD4+ and IFNγ+CD8+ T cell responses. Prime–boost vaccination of rhesus macaques (Macaca mulatta) with the BNT162b candidates elicits SARS-CoV-2-neutralizing geometric mean titres that are 8.2–18.2× that of a panel of SARS-CoV-2-convalescent human sera. The vaccine candidates protect macaques against challenge with SARS-CoV-2; in particular, BNT162b2 protects the lower respiratory tract against the presence of viral RNA and shows no evidence of disease enhancement. Both candidates are being evaluated in phase I trials in Germany and the USA1–3, and BNT162b2 is being evaluated in an ongoing global phase II/III trial (NCT04380701 and NCT04368728). BNT162b1 and BNT162b2 are two candidate mRNA vaccines against COVID-19 that elicit high virus-entry inhibition titres in mice, elicit high virus-neutralizing titres in rhesus macaques and protect macaques from SARS-CoV-2 challenge.

Active immunization with the BNT162b2 vaccine (Pfizer-BioNTech) has been a critical mitigation tool against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during the coronavirus disease 2019 (Covid-19) pandemic. In light of reports of waning protection occurring 6 months after the primary two-dose vaccine series, data are needed on the safety and efficacy of offering a third (booster) dose in persons 16 years of age or older.In this ongoing, placebo-controlled, randomized, phase 3 trial, we assigned participants who had received two 30-μg doses of the BNT162b2 vaccine at least 6 months earlier to be injected with a third dose of the BNT162b2 vaccine or with placebo. We assessed vaccine safety and efficacy against Covid-19 starting 7 days after the third dose.A total of 5081 participants received a third BNT162b2 dose and 5044 received placebo. The median interval between dose 2 and dose 3 was 10.8 months in the vaccine group and 10.7 months in the placebo group; the median follow-up was 2.5 months. Local and systemic reactogenicity events from the third dose were generally of low grade. No new safety signals were identified, and no cases of myocarditis or pericarditis were reported. Among the participants without evidence of previous SARS-CoV-2 infection who could be evaluated, Covid-19 with onset at least 7 days after dose 3 was observed in 6 participants in the vaccine group and in 123 participants in the placebo group, which corresponded to a relative vaccine efficacy of 95.3% (95% confidence interval, 89.5 to 98.3).A third dose of the BNT162b2 vaccine administered a median of 10.8 months after the second dose provided 95.3% efficacy against Covid-19 as compared with two doses of the BNT162b2 vaccine during a median follow-up of 2.5 months. (Funded by BioNTech and Pfizer; C4591031 ClinicalTrials.gov number, NCT04955626.).

BNT162b2 Vaccine and Emerging SARS-CoV-2 Variants A total of 20 serum samples from 15 persons who received the BNT162b2 vaccine showed strong neutralization activity against recombinant viruses eng...

An effective vaccine is needed to halt the spread of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic. Recently, we reported safety, tolerability and antibody response data from an ongoing placebo-controlled, observer-blinded phase I/II coronavirus disease 2019 (COVID-19) vaccine trial with BNT162b1, a lipid nanoparticle-formulated nucleoside-modified mRNA that encodes the receptor binding domain (RBD) of the SARS-CoV-2 spike protein1. Here we present antibody and T cell responses after vaccination with BNT162b1 from a second, non-randomized open-label phase I/II trial in healthy adults, 18–55 years of age. Two doses of 1–50 μg of BNT162b1 elicited robust CD4+ and CD8+ T cell responses and strong antibody responses, with RBD-binding IgG concentrations clearly above those seen in serum from a cohort of individuals who had recovered from COVID-19. Geometric mean titres of SARS-CoV-2 serum-neutralizing antibodies on day 43 were 0.7-fold (1-μg dose) to 3.5-fold (50-μg dose) those of the recovered individuals. Immune sera broadly neutralized pseudoviruses with diverse SARS-CoV-2 spike variants. Most participants had T helper type 1 (TH1)-skewed T cell immune responses with RBD-specific CD8+ and CD4+ T cell expansion. Interferon-γ was produced by a large fraction of RBD-specific CD8+ and CD4+ T cells. The robust RBD-specific antibody, T cell and favourable cytokine responses induced by the BNT162b1 mRNA vaccine suggest that it has the potential to protect against COVID-19 through multiple beneficial mechanisms. In a phase I/II dose-escalation clinical trial, the mRNA COVID-19 vaccine BNT162b1 elicits specific T cell and antibody responses that suggest it has protective potential.

In March 2020, the World Health Organization (WHO) declared coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)1, a pandemic. With rapidly accumulating numbers of cases and deaths reported globally2, a vaccine is urgently needed. Here we report the available safety, tolerability and immunogenicity data from an ongoing placebo-controlled, observer-blinded dose-escalation study (ClinicalTrials.gov identifier NCT04368728) among 45 healthy adults (18–55 years of age), who were randomized to receive 2 doses—separated by 21 days—of 10 μg, 30 μg or 100 μg of BNT162b1. BNT162b1 is a lipid-nanoparticle-formulated, nucleoside-modified mRNA vaccine that encodes the trimerized receptor-binding domain (RBD) of the spike glycoprotein of SARS-CoV-2. Local reactions and systemic events were dose-dependent, generally mild to moderate, and transient. A second vaccination with 100 μg was not administered because of the increased reactogenicity and a lack of meaningfully increased immunogenicity after a single dose compared with the 30-μg dose. RBD-binding IgG concentrations and SARS-CoV-2 neutralizing titres in sera increased with dose level and after a second dose. Geometric mean neutralizing titres reached 1.9–4.6-fold that of a panel of COVID-19 convalescent human sera, which were obtained at least 14 days after a positive SARS-CoV-2 PCR. These results support further evaluation of this mRNA vaccine candidate. In a dose-escalation study of the COVID-19 RNA vaccine BNT162b1 in 45 healthy adults, RBD-binding IgG concentrations and SARS-CoV-2 neutralizing titres in sera increased with dose level and after a second vaccine dose.

We report the antibody neutralization against Omicron SARS-CoV-2 after 2 and 3 doses of BNT162b2 mRNA vaccine. Vaccinated individuals were serially tested for their neutralization against wild-type SARS-CoV-2 (strain USA-WA1/2020) and an engineered USA-WA1/2020 bearing the Omicron spike glycoprotein. Plaque reduction neutralization results showed that at 2 or 4 weeks post-dose-2, the neutralization geometric mean titers (GMTs) were 511 and 20 against the wild-type and Omicron-spike viruses, respectively, suggesting that two doses of BNT162b2 were not sufficient to elicit robust neutralization against Omicron; at 1 month post-dose-3, the neutralization GMTs increased to 1342 and 336, respectively, indicating that three doses of vaccine increased the magnitude and breadth of neutralization against Omicron; at 4 months post-dose-3, the neutralization GMTs decreased to 820 and 171, respectively, suggesting similar neutralization decay kinetics for both variants. The data support a three-dose vaccine strategy and provide the first glimpse of the neutralization durability against Omicron.

The globally circulating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant of concern Omicron (B.1.1.529) has a large number of mutations, especially in the spike protein, indicating that recognition by neutralizing antibodies may be compromised. We tested Wuhan (Wuhan-Hu-1 reference strain), Beta (B.1.351), Delta (B.1.617.2), or Omicron pseudoviruses with sera of 51 participants who received two or three doses of the messenger RNA (mRNA)–based COVID-19 vaccine BNT162b2. After two doses, Omicron-neutralizing titers were reduced >22-fold compared with Wuhan-neutralizing titers. One month after the third vaccine dose, Omicron-neutralizing titers were increased 23-fold relative to their levels after two doses and were similar to levels of Wuhan-neutralizing titers after two doses. The requirement of a third vaccine dose to effectively neutralize Omicron was confirmed with sera from a subset of participants using live SARS-CoV-2. These data suggest that three doses of the mRNA vaccine BNT162b2 may protect against Omicron-mediated COVID-19.

A new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineage, B.1.1.529, was recently detected in Botswana and South Africa and is now circulating globally. Just two days after it was first reported to the World Health Organization (WHO), this strain was classified as a variant of concern (VOC) and named Omicron. Omicron has an unusually large number of mutations, including up to 39 amino acid modifications in the spike (S) protein, raising concerns that its recognition by neutralizing antibodies from convalescent and vaccinated individuals may be severely compromised. In this study, we tested pseudoviruses carrying the SARS-CoV-2 spike glycoproteins of either the Wuhan reference strain, the Beta, the Delta or the Omicron variants of concern with sera of 51 participants that received two doses or a third dose (≥6 months after dose 2) of the mRNA-based COVID-19 vaccine BNT162b2. Immune sera from individuals who received two doses of BNT162b2 had more than 22-fold reduced neutralizing titers against the Omicron as compared to the Wuhan pseudovirus. One month after a third dose of BNT162b2, the neutralization titer against Omicron was increased 23-fold compared to two doses and antibody titers were similar to those observed against the Wuhan pseudovirus after two doses of BNT162b2. These data suggest that a third dose of BNT162b2 may protect against Omicron-mediated COVID-19, but further analyses of longer-term antibody persistence and real-world effectiveness data are needed.

Background Safe, effective vaccines against coronavirus disease 2019 (Covid-19) are urgently needed in children younger than 12 years of age. Methods A phase 1, dose-finding study and an ongoing phase 2-3 randomized trial are being conducted to investigate the safety, immunogenicity, and efficacy of two doses of the BNT162b2 vaccine administered 21 days apart in children 6 months to 11 years of age. We present results for 5-to-11-year-old children. In the phase 2-3 trial, participants were randomly assigned in a 2:1 ratio to receive two doses of either the BNT162b2 vaccine at the dose level identified during the open-label phase 1 study or placebo. Immune responses 1 month after the second dose of BNT162b2 were immunologically bridged to those in 16-to-25-year-olds from the pivotal trial of two 30-μg doses of BNT162b2. Vaccine efficacy against Covid-19 at 7 days or more after the second dose was assessed. Results During the phase 1 study, a total of 48 children 5 to 11 years of age received 10 μg, 20 μg, or 30 μg of the BNT162b2 vaccine (16 children at each dose level). On the basis of reactogenicity and immunogenicity, a dose level of 10 μg was selected for further study. In the phase 2-3 trial, a total of 2268 children were randomly assigned to receive the BNT162b2 vaccine (1517 children) or placebo (751 children). At data cutoff, the median follow-up was 2.3 months. In the 5-to-11-year-olds, as in other age groups, the BNT162b2 vaccine had a favorable safety profile. No vaccine-related serious adverse events were noted. One month after the second dose, the geometric mean ratio of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing titers in 5-to-11-year-olds to those in 16-to-25-year-olds was 1.04 (95% confidence interval [CI], 0.93 to 1.18), a ratio meeting the prespecified immunogenicity success criterion (lower bound of two-sided 95% CI, >0.67; geometric mean ratio point estimate, ≥0.8). Covid-19 with onset 7 days or more after the second dose was reported in three recipients of the BNT162b2 vaccine and in 16 placebo recipients (vaccine efficacy, 90.7%; 95% CI, 67.7 to 98.3). Conclusions A Covid-19 vaccination regimen consisting of two 10-μg doses of BNT162b2 administered 21 days apart was found to be safe, immunogenic, and efficacious in children 5 to 11 years of age. (Funded by BioNTech and Pfizer; ClinicalTrials.gov number, NCT04816643.).

BNT162b2-elicited human sera neutralize the currently dominant Delta SARS-CoV-2 variant. Here, we report the ability of 20 human sera, drawn 2 or 4 weeks after two doses of BNT162b2, to neutralize USA-WA1/2020 SARS-CoV-2 bearing variant spikes from Delta plus (Delta-AY.1, Delta-AY.2), Delta-∆144 (Delta with the Y144 deletion of the Alpha variant), Lambda, B.1.1.519, Theta, and Mu lineage viruses. Geometric mean plaque reduction neutralization titers against Delta-AY.1, Delta-AY.2, and Mu viruses are slightly lower than against USA-WA1/2020, but all sera neutralize the variant viruses to titers of ≥80, and neutralization titers against the Delta-∆144, Lambda, B.1.1.519 and Theta variants not significantly reduced relative to those against USA-WA1/2020. The susceptibility of Delta plus, Lambda, B.1.1.519, Theta, Mu, and other variants to neutralization by the sera indicates that antigenic change has not led to virus escape from vaccine-elicited neutralizing antibodies and supports ongoing mass immunization with BNT162b2 to control the variants and to minimize the emergence of new variants.

BNT162b2-elicited human sera are known to neutralize the currently dominant Delta SARS-CoV-2 variant. Here, we report the ability of 20 human sera, drawn 2 or 4 weeks after two doses of BNT162b2, to neutralize USA-WA1/2020 SARS-CoV-2 bearing variant spikes from Delta plus (Delta-AY.1, Delta-AY.2), Delta-Δ144 (Delta with the Y144 deletion of the Alpha variant), Lambda, and B. 1.1.519 lineage viruses. Geometric mean plaque reduction neutralization titers against Delta-AY.1, Delta-AY.2, and Delta-Δ144 viruses are slightly lower than against USA-WA1/2020, but all sera neutralize the variant viruses to titers of ≥80.Neutralization titers against Lambda and B. 1.1.519 variants and against USA-WA1/2020 are equivalent. The susceptibility of Delta plus, Lambda, and other variants to neutralization by the sera indicates that antigenic change has not led to virus escape from vaccine-elicited neutralizing antibodies and supports ongoing mass immunization with BNT162b2 to control the variants and to minimize the emergence of new variants.

Immune Response to a Third Dose of BNT162b2 A third dose of the BNT162b2 vaccine was administered to 23 volunteers 8 to 9 months after the second dose, and the immune response was assessed. Local r...

BackgroundBNT162b2 is a lipid nanoparticle-formulated, nucleoside-modified RNA vaccine encoding a prefusion-stabilized, membrane-anchored SARS-CoV-2 full-length spike protein. BNT162b2 is highly efficacious against COVID-19 and is currently authorized for emergency use or conditional approval worldwide. At the time of authorization, data beyond 2 months post-vaccination were unavailable.MethodsIn an ongoing, placebo-controlled, observer-blinded, multinational, pivotal efficacy study, 44,165 ≥16-year-old participants and 2,264 12-15-year-old participants were randomized to receive 2 doses, 21 days apart, of 30 µg BNT162b2 or placebo. Study endpoints reported here are vaccine efficacy (VE) against laboratory-confirmed COVID-19 and safety data, both up to 6 months post-vaccination.ResultsBNT162b2 continued to be safe and well tolerated. Few participants had adverse events leading to study withdrawal. VE against COVID-19 was 91% (95% CI 89.0-93.2) through up to 6 months of follow-up, among evaluable participants and irrespective of previous SARS-CoV-2 infection. VE of 86%-100% was seen across countries and in populations with diverse characteristics of age, sex, race/ethnicity, and COVID-19 risk factors in participants without evidence of previous SARS-CoV-2 infection. VE against severe disease was 97% (95% CI 80.3−99.9). In South Africa, where the SARS-CoV-2 variant of concern, B.1.351 (beta), was predominant, 100% (95% CI 53.5, 100.0) VE was observed.ConclusionWith up to 6 months of follow-up and despite a gradually declining trend in vaccine efficacy, BNT162b2 had a favorable safety profile and was highly efficacious in preventing COVID-19. (ClinicalTrials.govnumber,NCT04368728)

BackgroundPrevention of respiratory syncytial virus (RSV) disease in infants is an unmet vaccine need, and maternal immunization is a potential strategy to address this need. This study evaluated concomitant administration of RSV stabilized prefusion F subunit vaccine (RSVpreF) and tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine adsorbed (Tdap) in healthy, nonpregnant women 18‒49 years of age.MethodsIn this phase 2b, multicenter, placebo-controlled, observer-blind, noninferiority study, participants were randomized to receive RSVpreF in a range of doses and formulations with Tdap or alone, or Tdap alone. Safety and immunogenicity were assessed.ResultsLocal reactions and systemic events were generally similar across vaccine groups. Noninferiority of anti-RSV-A and anti-RSV-B immune responses induced by RSVpreF with Tdap was demonstrated compared to RSVpreF alone. Noninferiority of anti-diphtheria toxoid and anti-tetanus toxoid immune responses after administration of RSVpreF with Tdap was demonstrated compared to Tdap alone; noninferiority was not met for anti-pertussis component responses.ConclusionsRSVpreF was safe and well tolerated when administered with Tdap or alone in nonpregnant women 18‒49 years of age. Immune responses induced by Tdap administered with RSVpreF were noninferior for the tetanus and diphtheria components of Tdap, but not for pertussis.Clinical Trials RegistrationNCT04071158.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve around the world, generating new variants that are of concern based on their potential for altered transmissibility, pathogenicity, and coverage by vaccines and therapeutics. Here we report that 20 BNT162b2 vaccine-elicited human sera neutralize engineered SARS-CoV-2 with a USA-WA1/2020 genetic background (a virus strain isolated in January 2020) and spike glycoproteins from the newly emerged B.1.617.1 (first identified in India) or B.1.525 (first identified in Nigeria) lineages. Geometric mean plaque reduction neutralization titers against the variant viruses, particularly the B.1.617.1 variant, are lower than the titer against USA-WA1/2020 virus, but all sera tested neutralize the variant viruses at titers of at least 40. The susceptibility of the newly emerged B.1.617.1 and B.1.525 variants to BNT162b2 vaccine-elicited neutralization supports mass immunization as a central strategy to end the COVID-19 pandemic across geographies.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is continuing to evolve around the world, generating new variants that are of concern on the basis of their potential for altered transmissibility, pathogenicity, and coverage by vaccines and therapeutic agents1–5. Here we show that serum samples taken from twenty human volunteers, two or four weeks after their second dose of the BNT162b2 vaccine, neutralize engineered SARS-CoV-2 with a USA-WA1/2020 genetic background (a virus strain isolated in January 2020) and spike glycoproteins from the recently identified B.1.617.1, B.1.617.2, B.1.618 (all of which were first identified in India) or B.1.525 (first identified in Nigeria) lineages. Geometric mean plaque reduction neutralization titres against the variant viruses—particularly the B.1.617.1 variant—seemed to be lower than the titre against the USA-WA1/2020 virus, but all sera tested neutralized the variant viruses at titres of at least 1:40. The susceptibility of the variant strains to neutralization elicited by the BNT162b2 vaccine supports mass immunization as a central strategy to end the coronavirus disease 2019 (COVID-19) pandemic globally. Samples of serum from individuals immunized with the BNT162b2 vaccine show neutralization activity against engineered SARS-CoV-2s bearing the spike mutations from B.1.617 and other variants.

Background Until very recently, vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had not been authorized for emergency use in persons younger than 16 years of age. Safe, effective vaccines are needed to protect this population, facilitate in-person learning and socialization, and contribute to herd immunity. Methods In this ongoing multinational, placebo-controlled, observer-blinded trial, we randomly assigned participants in a 1:1 ratio to receive two injections, 21 days apart, of 30 μg of BNT162b2 or placebo. Noninferiority of the immune response to BNT162b2 in 12-to-15-year-old participants as compared with that in 16-to-25-year-old participants was an immunogenicity objective. Safety (reactogenicity and adverse events) and efficacy against confirmed coronavirus disease 2019 (Covid-19; onset, ≥7 days after dose 2) in the 12-to-15-year-old cohort were assessed. Results Overall, 2260 adolescents 12 to 15 years of age received injections; 1131 received BNT162b2, and 1129 received placebo. As has been found in other age groups, BNT162b2 had a favorable safety and side-effect profile, with mainly transient mild-to-moderate reactogenicity (predominantly injection-site pain [in 79 to 86% of participants], fatigue [in 60 to 66%], and headache [in 55 to 65%]); there were no vaccine-related serious adverse events and few overall severe adverse events. The geometric mean ratio of SARS-CoV-2 50% neutralizing titers after dose 2 in 12-to-15-year-old participants relative to 16-to-25-year-old participants was 1.76 (95% confidence interval [CI], 1.47 to 2.10), which met the noninferiority criterion of a lower boundary of the two-sided 95% confidence interval greater than 0.67 and indicated a greater response in the 12-to-15-year-old cohort. Among participants without evidence of previous SARS-CoV-2 infection, no Covid-19 cases with an onset of 7 or more days after dose 2 were noted among BNT162b2 recipients, and 16 cases occurred among placebo recipients. The observed vaccine efficacy was 100% (95% CI, 75.3 to 100). Conclusions The BNT162b2 vaccine in 12-to-15-year-old recipients had a favorable safety profile, produced a greater immune response than in young adults, and was highly effective against Covid-19. (Funded by BioNTech and Pfizer; C4591001 ClinicalTrials.gov number, NCT04368728.)

Variant SARS-CoV-2 and BNT162b2 Vaccine How well do serum samples obtained from persons injected with the BNT162b2 vaccine neutralize the P.1, B.1.1.7, and B.1.135 lineages of SARS-CoV-2, first ide...

We engineered three severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viruses containing key spike mutations from the newly emerged United Kingdom (UK) and South African (SA) variants: N501Y from UK and SA; 69/70-deletion + N501Y + D614G from UK; and E484K + N501Y + D614G from SA. Neutralization geometric mean titers (GMTs) of 20 BTN162b2 vaccine-elicited human sera against the three mutant viruses were 0.81- to 1.46-fold of the GMTs against parental virus, indicating small effects of these mutations on neutralization by sera elicited by two BNT162b2 doses. Human sera from recipients of the BNT162b2 vaccine can neutralize SARS-CoV-2 viruses containing spike mutations present in globally circulating variants of concern.

Rapidly spreading variants of SARS-CoV-2 that have arisen in the United Kingdom and South Africa share the spike N501Y substitution, which is of particular concern because it is located in the viral receptor binding site for cell entry and increases binding to the receptor (angiotensin converting enzyme 2). We generated isogenic N501 and Y501 SARS-CoV-2. Sera of 20 participants in a previously reported trial of the mRNA-based COVID-19 vaccine BNT162b2 had equivalent neutralizing titers to the N501 and Y501 viruses.

Recently, a new SARS-CoV-2 lineage called B.1.1.7 has emerged in the United Kingdom that was reported to spread more efficiently than other strains. This variant has an unusually large number of mutations with 10 amino acid changes in the spike protein, raising concerns that its recognition by neutralizing antibodies may be affected. Here, we investigated SARS-CoV-2-S pseudoviruses bearing either the Wuhan reference strain or the B.1.1.7 lineage spike protein with sera of 16 participants in a previously reported trial with the mRNA-based COVID-19 vaccine BNT162b2. The immune sera had equivalent neutralizing titers to both variants. These data, together with the combined immunity involving humoral and cellular effectors induced by this vaccine, make it unlikely that the B.1.1.7 lineage will escape BNT162b2-mediated protection.