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Background: Unequal and inequitable access to Covid-19 vaccines in low- and middle-income countries (L&MICs) was a major political, ethical and public health failure in the pandemic. However, vaccine developers' practices were not monolithic, but rather, took diverse approaches to supplying different countries, with important implications for global access., Results: Using data on R&D investments, regulatory approvals, manufacturing and purchase agreements, and vaccine deliveries, we identified six distinct innovation models that apply across the 14 COVID-19 vaccines with more international presence from 2020-2022. "Western Early Arrivers" Pfizer/BioNTech and Moderna supplied the largest volumes quickly and prioritized high-income countries (HICs) from registration to vaccine delivery. "Western Latecomers" Janssen and Novavax supplied intermediate volumes later, also prioritizing HICs but with a greater proportion to L&MICs. "Major Chinese Developers" Sinopharm and Sinovac supplied intermediate volumes early, primarily to middle-income countries (MICs). "Russian Developer" Gamaleya completed development early but ultimately supplied small volumes, primarily to middle-income countries (MICs). "Cosmopolitan Developer" Oxford/AstraZeneca supplied large volumes early to HICs and MICs at the lowest prices. Finally, "Small MIC Developers" CanSino, Bharat Biotech, Medigen, Finlay Institute and the Center for Genetic Engineering and Biotechnology (CGEB), exported relatively small volumes to a few MICs. Low-income countries (LICs) were not targeted by any developer, and received far fewer doses, later, than any other income group. Almost all developers received public funding and other forms of support, but we found little evidence that such support was leveraged to expand global access., Conclusions: Each of the six innovation models has different implications for which countries get access to which vaccines, how quickly, and at which prices. Each offers different strengths and weaknesses for achieving equitable access. Our findings also suggest that Western firms had the greatest capacity to develop and deliver vaccines quickly during the pandemic, but such capacity is rapidly becoming more globally distributed with MICs playing a significant role, especially in supplying other MICs. Given the critical role of public support in enabling pandemic vaccine development and supply, governments have both the capacity and responsibility to craft international rules that will make responses to future pandemics more equitable and effective., (© 2024. The Author(s).)

Importance: The effect of coronavirus disease 2019 (COVID-19) vaccination on fertility warrants clarification in women undergoing assisted reproductive treatment., Objective: To study the association between female COVID-19 vaccination and outcomes of assisted reproductive treatment., Data Sources: PubMed, Embase, the Web of Science, Cochrane Library, and medRxiv and bioRxiv were searched for eligible studies from December 1, 2019, to November 30, 2022, with no language restrictions., Study Selection and Synthesis: Observational studies comparing assisted reproductive outcomes between women with and without COVID-19 vaccination were included. The pooled estimates were calculated using the random-effects models as mean differences (MDs), standardized MDs, or odds ratios with 95% confidence intervals (CIs). Heterogeneity was evaluated using the I 2 statistic., Main Outcomes: The number of oocytes retrieved and clinical pregnancy rate., Results: Twenty-one cohort studies involving a total of 19,687 treatment cycles were included. In a comparison of the vaccinated vs. unvaccinated groups, the pooled MD for oocyte number was -0.06 (95% CI, -0.51 to 0.39; I 2 = 0), and the pooled odds ratio for clinical pregnancy was 0.95 (95% CI, 0.85-1.05; I 2 = 0). Similarly, there were no statistically significant adverse effects identified in other outcomes determined a priori, including 4 cycle characteristics, 6 laboratory parameters, and 3 pregnancy indicators. Most results were consistently unchanged in subgroup and sensitivity analyses, with no evidence of publication bias according to Egger's test., Conclusion and Relevance: Our work did not find significant differences in assisted reproductive outcomes between vaccinated and unvaccinated women. However, more data are warranted to confirm the safety of COVID-19 vaccination for assisted reproductive treatment and in female fertility in general., (Copyright © 2023. Published by Elsevier Inc.)

Objective: To investigate the effect of inactivated coronavirus disease 2019 (COVID-19) vaccination on frozen-thawed embryo transfer (FET) outcomes., Methods: This retrospective cohort study enrolled 1,210 patients undergoing FET cycles in a single university-affiliated hospital between July 1, 2021, and May 1, 2022. Of them, 387 women with two full doses of inactivated SARS-CoV-2 vaccines (CoronaVac or BBIBP-CorV) after oocyte retrieval were assigned to the vaccinated group, while 823 were unvaccinated as controls. Propensity score matching and multiple regression analysis were applied to control for baseline and cycle characteristics (19 covariates in total)., Results: There were 265 patients in each group after matching. The rates of clinical pregnancy (58.5% vs. 60.8%; P = 0.595) and live birth (44.4% vs. 48.8%; P = 0.693) were similar between vaccinated and unvaccinated patients, with adjusted odds ratios of 0.89 (95% confidence interval [CI] 0.61-1.29) and 1.31 (95% CI 0.37-4.56), respectively. Consistently, no significant differences were found in serum human chorionic gonadotropin levels as well as biochemical pregnancy, biochemical pregnancy loss, and embryo implantation rates. Based on the time interval from vaccination to FET, vaccinated patients were further subdivided into two categories of ≤2 months and >2 months, and the outcomes remained comparable., Conclusion: Our study showed that inactivated COVID-19 vaccination in women did not have measurable detrimental impact on implantation performance and live birth outcome during FET treatment cycles. This finding denies the impairment of endometrial receptivity and trophoblast function by vaccine-induced antibodies at the clinical level., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The aim of this study was to investigate the effect of coronavirus disease 2019 (COVID-19) vaccination on semen parameters through systematic review and meta-analysis. PubMed, EMBASE, Web of Science, and Cochrane Library were comprehensively searched by June 2022. Studies were considered eligible if they compared semen parameters before and after COVID-19 vaccination or between vaccinated and unvaccinated men, with no restrictions on vaccine types or doses. The effect size was calculated as mean difference (MD) with 95% confidence interval (CI) using a random-effects model. Subgroup and sensitivity analyses were conducted to assess the sources of heterogeneity measured by the I 2 statistic, with publication bias evaluated by Egger's test. Twelve cohort studies involving 914 participants fulfilled the inclusion criteria. In a comparison of vaccinated versus unvaccinated group, the pooled data revealed no significant differences in semen volume (MD = 0.18 ml, 95% CI -0.02 to 0.38), sperm concentration (MD = 1.16 million/ml, 95% CI -1.34 to 3.66), total sperm motility (MD = -0.14%, 95% CI -2.84 to 2.56), progressive sperm motility (MD = -1.06%, 95% CI -2.88 to 0.77), total sperm count (MD = 5.92 million, 95% CI -10.22 to 22.05), total motile sperm count (MD = 2.18 million, 95% CI -1.28 to 5.63), total progressively motile sperm count (MD = -3.87 million, 95% CI -13.16 to 5.43), and sperm morphology (MD = 0.07%, 95% CI -0.84 to 0.97). The results also remained similar across messenger ribonucleic acid, viral-vector, and inactivated COVID-19 vaccines. Sensitivity analysis identified two individual studies that contributed to heterogeneity, while the effect size was not materially altered. No obvious publication bias was detected among included studies. Our finding suggested that COVID-19 vaccination had no detrimental impact on semen quality, which could be potentially helpful to reduce male vaccine hesitancy and increase vaccination coverage., (© 2022 Wiley Periodicals LLC.)

Objectives: To investigate the relationship between prior coronavirus disease 2019 (COVID‐19) infection in females and subsequent treatment outcomes of assisted reproductive technology (ART). Methods: A systematic literature review was carried out up to 16 December 2022, in PubMed, Web of Science, EMBASE, and Cochrane Library. Random‐effect models were adopted to estimate the pooled effects as mean differences (MDs) or odds ratios (ORs). I2 statistic and Egger's test were applied to assess heterogeneity and publication bias, respectively. Results: After screening 1480 records, 15 cohort studies totalling 1905 cycles were included in this meta‐analysis. In a comparison of previously COVID‐19‐infected versus uninfected women, no significant differences were observed in the primary outcomes of the retrieved oocytes number (MD = 0.06; 95% confidence interval [CI]: ‐0.75–0.88; I2 = 0) and clinical pregnancy rate (OR = 0.96; 95% CI: 0.74–1.24; I2 = 0). Pooled analyses of other predefined outcomes, which encompassed four cycle characteristics, six laboratory indicators and four pregnancy results, also showed no adverse effects of prior COVID‐19 infection. Most outcomes remained consistent after further sensitivity and subgroup analyses, and no significant publication bias was observed. Conclusions: Our work provides the first systematic evidence that COVID‐19 infection history in females may have no measurable detrimental impact on the subsequent ART cycle. More data are needed to assess the live birth outcome and the optimal time interval from infection to assisted reproduction. [ABSTRACT FROM AUTHOR]

Background and Aims: Despite widespread vaccination against hepatitis B and availability of antiviral drugs, hepatitis B remained a major global public health problem. Therefore, an improved understanding of the burden of hepatitis B was required to help design strategies for global intervention. Methods: Data on hepatitis B was collected by the Global Burden of Disease (GBD) 2019 database from 1990 to 2019. Age-standardized incidence rates (ASIR), mortality rates (ASMR) and disability-adjusted life year rates (ASDR) for hepatitis B were extracted from GBD 2019 and stratified by age, level of regionals and country. Estimated annual percentage changes (EAPC) of ASIR, ASMR and ASDR were calculated to quantify the temporal trends in hepatitis B. Results: Globally, ASIR showed a continuous downward trend, from 1552.2 in 1990 to 1010.0 per 100,000 persons in 2019, with an annual decrease of 1.52% (95% CI − 1.66--1.38). ASMR showed a persistent decline, declining by nearly half in 2019 compared to 1990 (6.7 vs 12.4 per 100,000 persons), with an annual decrease of 2.55% (95% CI − 2.74--2.35). ASDR showed a continuing downward trend, and the EAPC was − 2.55% (95% CI − 2.74--2.35). This decreasing pattern was heterogeneous across regions and countries. Hepatitis B related deaths increased significantly in high socio-demographic index countries such as UK, USA, and Canada. The ARIMA model estimates a 36.14% and 6.00% decrease in ASIR and ASMR, respectively, by 2030 compared to 2015. Conclusion: Global hepatitis B morbidity and mortality rates decreased significantly from 1990 to 2019, but with a high degree of heterogeneity among regions and countries. It was still far from achieving the WHO goal of elimination of viral hepatitis by 2030, especially mortality rate. [ABSTRACT FROM AUTHOR]