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Observational Study
. 2022 Oct;22(10):1435-1443.
doi: 10.1016/S1473-3099(22)00345-0. Epub 2022 Jul 15.

Vaccine effectiveness of one, two, and three doses of BNT162b2 and CoronaVac against COVID-19 in Hong Kong: a population-based observational study

Martina E McMenamin  1 , Joshua Nealon  2 , Yun Lin  1 , Jessica Y Wong  1 , Justin K Cheung  1 , Eric H Y Lau  3 , Peng Wu  3 , Gabriel M Leung  3 , Benjamin J Cowling  4
Affiliations
Observational Study

Vaccine effectiveness of one, two, and three doses of BNT162b2 and CoronaVac against COVID-19 in Hong Kong: a population-based observational study

Martina E McMenamin et al. Lancet Infect Dis. 2022 Oct.

Erratum in

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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Conflict of interest statement

Declaration of interests BJC reports honoraria from AstraZeneca, Fosun Pharma, GlaxoSmithKline, Moderna, Pfizer, Roche, and Sanofi Pasteur. JN was previously employed by and owns shares in Sanofi. All other authors declare no competing interests.

Figures

Figure 1
Figure 1
Daily incidence of cases and deaths by vaccination status (A) All confirmed COVID-19 cases. (B) Mild or moderate cases in the early part of the fifth wave before Feb 15, 2022. (C) Severe or fatal cases. (D) Deaths throughout the fifth wave in Hong Kong. Severe disease was defined as having ever been listed as serious or critical during hospitalisation for COVID-19 or having a fatal outcome within 28 days of positive test. Vaccination status was categorised according to the number of doses received plus a 14-day lag for all doses, to allow for the immune response to vaccination. Mild cases were only included up until Feb 15, 2022, to account for change in admission criteria.
Figure 2
Figure 2
Vaccine status, age group, and vaccine type
See this image and copyright information in PMC

References

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