Vaccine Effectiveness of Two and Three Doses of BNT162b2 and Coronavac Against COVID-19 in Hong Kong

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

doi:10.2139/ssrn.4064649

Cited by 38 publications

(37 citation statements)

References 15 publications

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“…23 For the Omicron period, our estimates are consistent with an ecological study from Hong Kong regarding the effectiveness of a primary vaccination with CoronaVac. 12 However, our estimates of vaccine effectiveness against severe disease for a homologous booster are lower than reported the study in Hong Kong. The differences in study design, previous attack rate in the population, time of follow-up, non-pharmaceutical interventions in place during the Omicron outbreak in Hong Kong, and limited sample size for severe disease in the Hong Kong study could explain these differences.…”

Section: Discussioncontrasting

confidence: 66%

“…The differences in study design, previous attack rate in the population, time of follow-up, non-pharmaceutical interventions in place during the Omicron outbreak in Hong Kong, and limited sample size for severe disease in the Hong Kong study could explain these differences. 12…”

Section: Discussionmentioning

confidence: 99%

“…11 Large Omicron epidemics associated with severe cases and deaths have been 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%

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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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Section: Discussioncontrasting

confidence: 66%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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“…We found that cases in persons who had a complete primary series at age of 65-79 years or ≥80 years would have a much lower fatality risk (Figure 2, Supplementary Table 2). In a separate study, we estimated very high vaccine effectiveness against severe disease in older adults ≥60 years of age who received either three doses of the inactivated vaccine CoronaVac or two doses of BNT162b2 [22]. For adults ≥60 years of age, the World Health Organization recommend that three doses of inactivated vaccine are needed [23].…”

Section: Discussionmentioning

confidence: 99%

Epidemiology of infections with SARS-CoV-2 Omicron BA.2 variant in Hong Kong, January-March 2022

Mesfin

Chen

Bond

et al. 2022

Preprint

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Hong Kong reported 12,631 confirmed COVID-19 cases and 213 deaths in the first two years of the pandemic but experienced a major wave predominantly of Omicron BA.2.2 in early 2022 with over 1.1 million reported SARS-CoV-2 infections and more than 7900 deaths. Our data indicated a shorter incubation period, serial interval, and generation time of infections with Omicron than other SARS-CoV-2 variants. Omicron BA.2.2 cases without a complete primary vaccination series appeared to face a similar fatality risk to those infected in earlier waves with the ancestral strain.

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“…Nevertheless, we were able to conclude that third dose of mRNA vaccination would provide substantial benefits against both ancestral and Omicron strains. Our results on immunogenicity may be subjected to selection bias including volunteer bias, since in Hong Kong older adults are more inclined to receive the inactivated vaccines and younger adults to mRNA vaccines [29]. Our results on reactogenicity may be subjected to information bias as this was an open-label trial and it is recognized that there could be more post-vaccination reactions after mRNA vaccination compared to inactivated vaccination [30].…”

Section: Discussionmentioning

confidence: 99%

Immunogenicity of a third dose of BNT162b2 to ancestral SARS-CoV-2 & Omicron variant in adults who received two doses of inactivated vaccine

Leung

Cheng

Martín-Sánchez

et al. 2022

Preprint

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Limited data exist on antibody responses to mixed vaccination strategies involving inactivated COVID-19 vaccines, particularly in the context of emerging variants. We conducted an open label trial and administered a third vaccine dose of an mRNA vaccine (BNT162b2, BioNTech/Fosun Pharma) in adults aged ≥30 years who had previously received two doses of an inactivated COVID-19 vaccine. We collected blood samples prior to administering the third dose and 28 days later, and tested for antibodies to the ancestral virus using a binding assay (ELISA), a surrogate virus neutralization test (sVNT) and a live virus plaque reduction neutralization test (PRNT), and to the Omicron variant using PRNT. A third dose of BNT162b2 substantially increased antibody titers on each assay. Mean ELISA levels increased from an optical density (OD) of 0.3 to 2.1 (p<0.01), and mean sVNT levels increased from an inhibition of 17% to 96% (p<0.01). In a random subset of 20 participants, the geometric mean PRNT50 titers rose very substantially by at least 27 fold from Day 0 to Day 28 against the ancestral virus (p<0.01) and rose by at least 14 fold against the Omicron variant (p<0.01). In daily monitoring, post-vaccination reactions subsided within 7 days for over 99% of participants. In conclusion, a third dose of COVID-19 vaccination with an mRNA vaccine substantially improved antibody levels against the ancestral virus and against the Omicron variant with well-tolerated safety profile, in adults who had received two doses of inactivated vaccine 6 months earlier.

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Vaccine Effectiveness of Two and Three Doses of BNT162b2 and Coronavac Against COVID-19 in Hong Kong

Cited by 38 publications

References 15 publications

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

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

Epidemiology of infections with SARS-CoV-2 Omicron BA.2 variant in Hong Kong, January-March 2022

Immunogenicity of a third dose of BNT162b2 to ancestral SARS-CoV-2 & Omicron variant in adults who received two doses of inactivated vaccine

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