{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T23:55:58Z","timestamp":1787874958063,"version":"build-2784847793"},"reference-count":32,"publisher":"American Medical Association (AMA)","issue":"8","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JAMA Netw Open"],"abstract":"Importance<\/jats:title>Assessing booster effectiveness of COVID-19 mRNA vaccine and inactivated SARS-CoV-2 vaccine over longer time intervals and in response to any further SARS-CoV-2 variants is crucial in determining optimal COVID-19 vaccination strategies.<\/jats:p><\/jats:sec>Objective<\/jats:title>To determine levels of protection against severe COVID-19 and confirmed SARS-CoV-2 infection by types and combinations of vaccine boosters in Singapore during the Omicron wave.<\/jats:p><\/jats:sec>Design, Setting, and Participants<\/jats:title>This cohort study included Singapore residents aged 30 years or more vaccinated with either at least 2 doses of mRNA COVID-19 vaccines (ie, Pfizer-BioNTech BNT162b2 or Moderna mRNA-1273) or inactivated SARS-CoV-2 vaccines (Sinovac CoronaVac or Sinopharm BBIBP-CorV) as of March 10, 2022. Individuals with a known SARS-CoV-2 infection prior to December 27, 2021, an infection on or before the date of their second vaccine dose, or with reinfection cases were excluded.<\/jats:p><\/jats:sec>Exposures<\/jats:title>Two or 3 doses of Pfizer-BioNTech BNT162b2, Moderna mRNA-1273, Sinovac CoronaVac, or Sinopharm BBIBP-CorV.<\/jats:p><\/jats:sec>Main Outcomes and Measures<\/jats:title>Notified infections from December 27, 2021, to March 10, 2022, adjusted for age, sex, race, housing status, and calendar days. Estimated booster effectiveness, defined as the relative incidence-rate reduction of severe disease (supplemental oxygen, intensive care, or death) or confirmed infection following 3-dose vaccination compared with 5 months after second mRNA dose, was determined using binomial regression.<\/jats:p><\/jats:sec>Results<\/jats:title>Among 2\u202f441\u202f581 eligible individuals (1\u202f279\u202f047 [52.4%] women, 846\u202f110 (34.7%) aged 60 years and older), there were 319\u202f943 (13.1%) confirmed SARS-CoV-2 infections, of which 1513 (0.4%) were severe COVID-19 cases. mRNA booster effectiveness against confirmed infection 15 to 60 days after boosting was estimated to range from 31.7% to 41.3% for the 4 boosting combinations (homologous BNT162b2, homologous mRNA-1273, 2-dose BNT162b2\/mRNA-1273 booster, and 2-dose mRNA-1273\/BNT162b2 booster). Five months and more after boosting, estimated booster effectiveness against confirmed infection waned, ranging from \u20132.8% to 14.6%. Against severe COVID-19, estimated mRNA booster effectiveness was 87.4% (95% CI, 83.3%-90.5%) 15 to 60 days after boosting and 87.2% (95% CI, 84.2%-89.7%) 5 to 6 months after boosting, with no significant difference comparing vaccine combinations. Booster effectiveness against severe COVID-19 15 days to 330 days after 3-dose inactivated COVID-19 vaccination, regardless of combination, was estimated to be 69.6% (95% CI, 48.7%-81.9%).<\/jats:p><\/jats:sec>Conclusions and Relevance<\/jats:title>Booster mRNA vaccine protection against severe COVID-19 was estimated to be durable over 6 months. Three-dose inactivated SARS-CoV-2 vaccination provided greater protection than 2-dose but weaker protection compared with 3-dose mRNA.<\/jats:p><\/jats:sec>","DOI":"10.1001\/jamanetworkopen.2022.28900","type":"journal-article","created":{"date-parts":[[2022,8,26]],"date-time":"2022-08-26T15:47:16Z","timestamp":1661528836000},"page":"e2228900","source":"Crossref","is-referenced-by-count":66,"title":["Analysis of COVID-19 Incidence and Severity Among Adults Vaccinated With 2-Dose mRNA COVID-19 or Inactivated SARS-CoV-2 Vaccines With and Without Boosters in Singapore"],"prefix":"10.1001","volume":"5","author":[{"given":"Oon Tek","family":"Ng","sequence":"first","affiliation":[{"name":"National Centre for Infectious Diseases, Singapore"},{"name":"Tan Tock Seng Hospital, Singapore"},{"name":"Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kalisvar","family":"Marimuthu","sequence":"additional","affiliation":[{"name":"National Centre for Infectious Diseases, Singapore"},{"name":"Tan Tock Seng Hospital, Singapore"},{"name":"Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nigel","family":"Lim","sequence":"additional","affiliation":[{"name":"Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ze Qin","family":"Lim","sequence":"additional","affiliation":[{"name":"National Centre for Infectious Diseases, Singapore"},{"name":"Tan Tock Seng Hospital, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Natascha May","family":"Thevasagayam","sequence":"additional","affiliation":[{"name":"National Centre for Infectious Diseases, Singapore"},{"name":"Tan Tock Seng Hospital, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vanessa","family":"Koh","sequence":"additional","affiliation":[{"name":"National Centre for Infectious Diseases, Singapore"},{"name":"Tan Tock Seng Hospital, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Calvin J.","family":"Chiew","sequence":"additional","affiliation":[{"name":"Communicable Diseases Division, Ministry of Health, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stefan","family":"Ma","sequence":"additional","affiliation":[{"name":"Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore"},{"name":"Public Health Group, Ministry of Health, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mingshi","family":"Koh","sequence":"additional","affiliation":[{"name":"Ministry of Health, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pin Yan","family":"Low","sequence":"additional","affiliation":[{"name":"Ministry of Health, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Say Beng","family":"Tan","sequence":"additional","affiliation":[{"name":"National Medical Research Council, Ministry of Health, Singapore"},{"name":"SingHealth, Singapore"},{"name":"Duke-National University of Singapore Medical School, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joses","family":"Ho","sequence":"additional","affiliation":[{"name":"Bioinformatics Institute, Agency for Science Technology and Research, Singapore"},{"name":"GISAID Global Data Science Initiative, Munich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sebastian","family":"Maurer-Stroh","sequence":"additional","affiliation":[{"name":"National Centre for Infectious Diseases, Singapore"},{"name":"Bioinformatics Institute, Agency for Science Technology and Research, Singapore"},{"name":"Infectious Diseases Labs, Agency for Science Technology and Research, Singapore"},{"name":"Department of Biological Sciences, National University of Singapore, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vernon J. M.","family":"Lee","sequence":"additional","affiliation":[{"name":"Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore"},{"name":"Communicable Diseases Division, Ministry of Health, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yee-Sin","family":"Leo","sequence":"additional","affiliation":[{"name":"National Centre for Infectious Diseases, Singapore"},{"name":"Tan Tock Seng Hospital, Singapore"},{"name":"Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore"},{"name":"Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore"},{"name":"Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kelvin Bryan","family":"Tan","sequence":"additional","affiliation":[{"name":"Saw Swee Hock 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