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

McMenamin, Martina; Nealon, Joshua; Lin, Yun; Wong, Jessica Y.; Cheung, Justin; Lau, Eric H Y; Wu, Peng; Leung, Gabriel M.; Cowling, Benjamin J.

doi:10.1016/s1473-3099(22)00345-0

Cited by 267 publications

(241 citation statements)

References 30 publications

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“…The booster shot was effective in slowing down the epidemics in both the Delta and Omicron-dominated periods with the average VPRs well above the 50% threshold. Our results on the real-world VPRs were consistent with the vaccine effectiveness in the existing cohort or case-control studies 9, 12, 16 . The necessity of the full and the booster vaccination are further highlighted by significant reductions in daily numbers of active confirmed cases in the scenario analyses.…”

Section: Discussionsupporting

confidence: 85%

Real-World COVID-19 Vaccine Protection Rates against Infection in the Delta and Omicron Eras

Zhu

Qiu

et al. 2022

Preprint

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The real-world protection rates of vaccination (VPRs) against the SARS-Cov-2 infection are critical in formulating future vaccination strategies against the virus. Based on a varying coefficient stochastic epidemic model, we obtain seven countries' real-world VPRs using daily epidemiological and vaccination data, and find that the VPRs improved with more vaccine doses. The average VPR of the full vaccination was 82% (SE: 4%) and 61% (SE: 3%) in the pre-Delta and Delta-dominated periods, respectively. The Omicron variant reduced the average VPR of the full vaccination to 39% (SE: 2%). However, the booster dose restored the VPR to 63% (SE: 1%) which was significantly above the 50% threshold in the Omicron-dominated period. Scenario analyses show that the existing vaccination strategies have significantly delayed and reduced the timing and the magnitude of the infection peaks, respectively, and doubling the existing booster coverage would lead to 29% fewer confirmed cases and 17% fewer deaths in the seven countries compared to the outcomes at the existing booster taking rates. These call for higher full vaccine and booster coverage for all countries.

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Section: Discussionsupporting

confidence: 85%

Real-World COVID-19 Vaccine Protection Rates against Infection in the Delta and Omicron Eras

Zhu

Qiu

et al. 2022

Preprint

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“…The database has been widely used for studies to evaluate the safety and effectiveness of drug treatments for COVID-19 at the population level. 12 , 13 …”

Section: Methodsmentioning

confidence: 99%

Real-world effectiveness of early molnupiravir or nirmatrelvir–ritonavir in hospitalised patients with COVID-19 without supplemental oxygen requirement on admission during Hong Kong's omicron BA.2 wave: a retrospective cohort study

Wong

Lau

et al. 2022

The Lancet Infectious Diseases

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“…11 Large Omicron epidemics associated with severe cases and deaths have occurred in regions, most recently Eastern Asia, where inactivated vaccines have been extensively administered. 12 Brazil initiated booster vaccination in September 2021, after Delta VoC began to dominate in the country and three months before Omicron dominance. 5 Evidence concerning the effectiveness of inactivated vaccines with homologous or heterologous boosters is critically needed to inform vaccine policies in countries that used these vaccines in their initial rollout.…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of an Inactivated Covid-19 Vaccine with Homologous and Heterologous Boosters against Omicron in Brazil

Ranzani

Hitchings

Melo

et al. 2022

Preprint

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Background Large outbreaks of the SARS-CoV-2 Omicron (B.1.1.529) variant have occurred in countries with high coverage of inactivated Covid-19 vaccines, raising urgent questions about effectiveness of these vaccines against disease and hospitalization with Omicron. Methods We conducted a nationwide, test-negative, case-control study of adults who were tested for SARS-CoV-2 infection. We evaluated vaccine effectiveness against symptomatic Covid-19 and severe Covid-19 (hospital admission or deaths) for the primary series of CoronaVac and homologous and heterologous (BNT162b2) booster doses. Findings Between September 6, 2021, and March 10, 2022, a total of 1,339,986 cases were matched to 1,339,986 test-negative controls. In the period of Omicron predominance, vaccine effectiveness ≥180 days after the second CoronaVac dose was 8.1% (95% CI, 7.0 to 9.1) and 57.0% (95% CI, 53.5 to 60.2) against symptomatic and severe Covid-19, respectively. Vaccine effectiveness against symptomatic disease was 15.0% (95% CI, 12.0 to 18.0) and 56.8% (95% CI, 56.3 to 57.4) in the period 8-59 days after receiving a homologous and heterologous booster, respectively. During the same interval, vaccine effectiveness against severe Covid-19 was 71.3% (95% CI, 60.3 to 79.2) and 85.5% (95% CI, 83.3 to 87.0) after receiving a homologous and heterologous booster, respectively. Whereas waning of vaccine effectiveness against symptomatic Covid-19 was observed ≥90 days after a homologous and heterologous booster, waning against severe Covid-19 was only observed after a homologous booster. Interpretation A homologous CoronaVac booster dose provided limited additional protection, while a BNT162b2 booster dose afforded sustained protection against severe disease for at least three months.

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

Cited by 267 publications

References 30 publications

Real-World COVID-19 Vaccine Protection Rates against Infection in the Delta and Omicron Eras

Real-World COVID-19 Vaccine Protection Rates against Infection in the Delta and Omicron Eras

Real-world effectiveness of early molnupiravir or nirmatrelvir–ritonavir in hospitalised patients with COVID-19 without supplemental oxygen requirement on admission during Hong Kong's omicron BA.2 wave: a retrospective cohort study

Effectiveness of an Inactivated Covid-19 Vaccine with Homologous and Heterologous Boosters against Omicron in Brazil

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