Lee IT, Cosgrove CA, Moore P, Bethune C, Nally R, Bula M, Kalra PA, Clark R, Dargan PI, Boffito M, Sheridan R, Moran E, Darton TC, Burns F, Saralaya D, Duncan CJA, Lillie PJ, San Francisco Ramos A, Galiza EP, Heath PT, Girard B, Parker C, Rust D, Mehta S, de Windt E, Sutherland A, Tomassini JE, Dutko FJ, Chalkias S, Deng W, Chen X, Feng J, Tracy L, Zhou H, Miller JM, and Das R
Background: The omicron BA.1 bivalent booster is used globally. Previous open-label studies of the omicron BA.1 (Moderna mRNA-1273.214) booster showed superior neutralising antibody responses against omicron BA.1 and other variants compared with the original mRNA-1273 booster. We aimed to compare the safety and immunogenicity of omicron BA.1 monovalent and bivalent boosters with the original mRNA-1273 vaccine in a large, randomised controlled trial., Methods: In this large, randomised, observer-blind, active-controlled, phase 3 trial in the UK (28 hospital and vaccination clinic sites), individuals aged 16 years or older who had previously received two injections of any authorised or approved COVID-19 vaccine, with or without an mRNA vaccine booster (third dose), were randomly allocated (1:1) using interactive response technology to receive 50 μg omicron BA.1 monovalent or bivalent vaccines or 50 μg mRNA-1273 administered as boosters via deltoid intramuscular injection. The primary outcomes were safety and immunogenicity at day 29, including prespecified non-inferiority and superiority of booster immune responses, based on the neutralising antibody geometric mean concentration (GMC) ratios of the monovalent and bivalent boosters compared with mRNA-1273. Safety was assessed in all participants who received first or second boosters, and primary immunogenicity outcomes were assessed in all participants who received the planned booster dose, had pre-booster and day 29 antibody data, had no major protocol deviations, and who were SARS-CoV-2-negative. The study is registered with EudraCT (2022-000063-51) and ClinicalTrials.gov (NCT05249829) and is ongoing., Findings: Between Feb 16 and March 24, 2022, 724 participants were randomly allocated to receive omicron BA.1 monovalent (n=366) or mRNA-1273 (n=357), and between April 2 and June 17, 2022, 2824 participants were randomly allocated to receive omicron BA.1 bivalent (n=1418) or mRNA-1273 (n=1395) vaccines as second boosters. Median durations (months) between the most recent COVID-19 vaccine and study boosters were similar for omicron BA.1 monovalent (4·0 months [IQR 3·6-4·7]) and mRNA-1273 (4·1 [3·5-4·7]), and for the omicron BA.1 bivalent (5·5 [4·8-6·2]) and mRNA-1273 (5·4 [4·8-6·2]) boosters. The omicron BA.1 monovalent and bivalent boosters elicited superior neutralising GMCs against the omicron BA.1 variant compared with mRNA-1273, with GMC ratios of 1·68 (99% CI 1·45-1·95) and 1·53 (1·41-1·67) at day 29 post-booster doses in participants without previous SARS-CoV-2 infection. Both boosters induced non-inferior ancestral SARS-CoV-2 (Asp614Gly) immune responses with GMCs that were similar for the bivalent (2987·2 [95% CI 2814·9-3169·9]) versus mRNA-1273 (2911·3 [2750·9-3081·0]) and lower for the monovalent (2699·7 [2431·3-2997·7] vs 3020·6 [2776·5-3286·2]) boosters, with respective GMC ratios of 1·05 (99% CI 0·96-1·15) and 0·82 (95% CI 0·74-0·91). Results were comparable regardless of previous SARS-CoV-2 infection status. Incidences of solicited adverse reactions with the omicron BA.1 monovalent (335 [91·3%] of 367 participants) and omicron BA.1 bivalent (1285 [90·4%] of 1421 participants) boosters were similar to those observed previously for mRNA-1273, with no new safety concerns identified and no occurrences of fatal adverse events., Interpretation: Omicron-containing booster vaccines generated superior immunogenicity against omicron BA.1 and comparable immunogenicity against the original strain with no new safety concerns. It remains important to continuously monitor the immune responses and real-world vaccine effectiveness as divergent SARS-CoV-2 variants emerge., Funding: Moderna., Competing Interests: Declaration of interests ITL, BG, CP, DR, SM, EdW, AS, SC, WD, XC, JF, LT, HZ, JMM, and RD are employees of Moderna and hold stock or stock options in the company. PM reports being a speaker or adviser for and receiving research grants from GSK, Sanofi, Novavax, Moderna, MSD, Janssen, Medicago, and AstraZeneca. CB reports being a National Specialty Advisor (NHS England) Immunology and Allergy and receiving funding to their institution to undertake vaccine trials for Janssen, Moderna, AstraZeneca, and Valneva. RN reports being Research Lead for Cambridge and Peterborough Integrated Care Board; and receiving grants from GSK and Novavax. PAK reports being a speaker or adviser for and receiving travel or research grants from GSK, Pfizer, Pharmacosmos, Astellas, Vifor, AstraZeneca, Bayer, Unicyte, Evotec, Fresenius, and Otsuka. PID reports receiving research grants for COVID-19 research studies from Moderna, AstraZeneca, Janssen, and Atea. MBo reports being a speaker or adviser for GSK, Atea, ViiV, MSD, Janssen, Gilead, Cipla, Mylan, and Roche; and receiving research grants from ViiV, MSD, Janssen, Gilead, Novavax, Valneva, and Moderna. FB reports receiving speaker fees and a research grant to their institution from Gilead Sciences. CJAD reports receiving grants from the Wellcome Trust and the Medical Research Council. ASFR reports receiving research grants (to their organisation) from Pfizer, Novavax, Valneva, Moderna, and Janssen. PTH reports being a speaker or adviser for and receiving research grants from Pfizer, Novavax, Valneva, Moderna, and Janssen. JET and FJD are Moderna contractors. All other authors declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)