Vaccine effectiveness of one, two, and three doses of BNT162b2 and CoronaVac against COVID-19 in Hong Kong: a population-based observational study
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Abstract
Background Hong Kong maintained low circulation of SARS-CoV-2 until a major community epidemic of the omicron (B.1.1.529) sublineage BA.2 began in January, 2022. Both mRNA (BNT162b2 [Fosun Pharma-BioNTech]) and inactivated CoronaVac (Sinovac, Beijing, China) vaccines are widely available; however, vaccination coverage has been low, particularly in older adults aged 70 years or older. We aimed to assess vaccine effectiveness in this predominantly infection-naive population. Methods In this observational study, we used individual-level case data on mild or moderate, severe or fatal, and fatal disease in patients hospitalised with COVID-19 along with census information and coverage data of BNT162b2 and CoronaVac. We used a negative binomial model, adjusting for age, sex, and calendar day to estimate vaccine effectiveness of one, two, and three doses of both BNT162b2 and CoronaVac vaccines, and relative effectiveness by number of doses and vaccine type. Findings Between Dec 31, 2020, and March 16, 2022, 13·2 million vaccine doses were administered in Hong Kong's 7·4-million population. We analysed data from confirmed cases with mild or moderate (n=5566), severe or fatal (n=8875), and fatal (n=6866) COVID-19. Two doses of either vaccine protected against severe disease and death within 28 days of a positive test, with higher effectiveness among adults aged 60 years or older with BNT162b2 (vaccine effectiveness 89·3% [95% CI 86·6-91·6]) compared with CoronaVac (69·9% [64·4-74·6]). Three doses of either vaccine offered very high levels of protection against severe or fatal outcomes (97·9% [97·3-98·4]). Interpretation Third doses of either BNT162b2 or CoronaVac provide substantial additional protection against severe COVID-19 and should be prioritised, particularly in older adults older than 60 years and others in high-risk populations who received CoronaVac primary schedules. Longer follow-up is needed to assess duration of protection across different vaccine platforms and schedules. Funding COVID-19 Vaccines Evaluation Program, Chinese Center for Disease Control and Prevention.
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Boosting by BNT162b2 or CoronaVac restores strong protection against hospitalization and death, but the incremental effectiveness of BNT162b2 boosters against such outcomes waned over 4-6 months for adults and the elderly.
“Further, although boosting by BNT162b2 or CoronaVac restores strong protection against hospitalization and death33–35, the incremental effectiveness of BNT162b2 boosters against such outcomes waned over the course of 4–6 months34 for both adults and the elderly36.”
From Real-world COVID-19 vaccine effectiveness against the Omicron BA.2 variant in a SARS-CoV-2 infection-naive population (2023) · cites this paper as [33]
The Results report that three recent doses of either vaccine provided very high protection against severe disease and death, and that a third dose added protection in adults of all ages. But the Discussion says protection after third doses could be estimated only over a short period and that its duration was unclear; the paper does not establish waning of BNT162b2 booster effectiveness over 4–6 months. (LLM, conf=0.89)
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- Authors
- McMenamin, M. E., Nealon, J., Lin, Y., Wong, J. Y., Cheung, J. K., Lau, E. H. Y., Wu, P., Leung, G. M., & Cowling, B. J.
- Affiliations
- University of Hong Kong (HK)
- Hong Kong Science and Technology Parks Corporation (HK)
- Corresponding author
- Nealon, Joshua
- Cowling, Benjamin J
- ORCID
- Venue
- The Lancet Infectious Diseases
- Publisher
- Elsevier BV
- Published
- 2022-10
- Volume
- 22
- Issue
- 10
- Pages
- 1435-1443
- ISSN
- 1473-3099 (ISSN-L)
- PMC
- PMC9286709
- OpenAlex
- W4285606826
- Cited by
- 360
- References
- 25
- Citations by year
- 2026: 19 · 2025: 37 · 2024: 90 · 2023: 125 · 2022: 89
- FWCI
- 41.59
- Type
- journal article
- Language
- en
- Update notices
- erratum (2022-09-01)
- Open access
- green
- doi.org
- Licence
- Locations
- The Lancet Infectious Diseases (publishedVersion)
- medRxiv (acceptedVersion, cc-by)
- SSRN Electronic Journal (acceptedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- Figshare (submittedVersion, cc-by)
- Funders
- Research Grants Council, University Grants Committee
- Chinese Center for Disease Control and Prevention National Institute for Nutrition and Health
- University Grants Committee (T11-712/19-N)
- Topics
- Health Sciences › Medicine › Infectious Diseases › SARS-CoV-2 and COVID-19 Research
- Social Sciences › Health › Vaccine Coverage and Hesitancy
- Health Sciences › Medicine › Infectious Diseases › COVID-19 Clinical Research Studies
- Keywords
- COVID-19 pandemic, SARS-CoV-2, BNT162b2, CoronaVac, vaccine effectiveness, booster vaccination, mRNA vaccines, inactivated vaccine, Omicron variant, severe COVID-19, COVID-19 mortality, older adults, Hong Kong, vaccination coverage, vaccine prioritization, duration of protection
- MeSH terms
- COVID-19, SARS-CoV-2, COVID-19 Vaccines, Vaccine Efficacy, BNT162 Vaccine, Aged, Hong Kong, Humans
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