Effectiveness of Homologous and Heterologous Booster Shots for an Inactivated SARS-CoV-2 Vaccine: A Large-Scale Observational Study

Jara, Alejandro; Undurraga, Eduardo A.; Zubizarreta, José R.; González, Cecilia; Pizarro, Alejandra; Acevedo, Johanna; Leo, Katherinne; Paredes, Fabio; Bralic, Tomás; Vergara, Verónica; Mosso, Marcelo; León, Francisco Cázares de; Parot, Ignacio; Leighton, Paulina; Suárez, Pamela; Ríos, Juan Carlos; García-Escorza, Heriberto; Araos, Rafael

doi:10.2139/ssrn.4005130

Cited by 9 publications

(11 citation statements)

References 16 publications

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“…Our findings on the effectiveness against severe Covid-19 of homologous and heterologous booster doses during the Delta period is consistent with a previous test-negative study in Brazil 5 and with a cohort study from Chile conducted during the same period. 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.…”

Section: Discussionsupporting

confidence: 86%

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: Discussionsupporting

confidence: 86%

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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“…Our analysis complements pre-Omicron findings that homologous boosting with AZD1222 in the United Kingdom [ 8 ] and CoronaVac in Brazil [ 9 ], and Omicron-specific findings in Hong Kong [ 1 ] that homologous CoronaVac boosting generated lower neutralizing antibodies than mRNA boosters. Pre-Omicron evidence from Chile [ 10 ] observed lower effectiveness for homologous than heterologous boosting in CoronaVac primary vaccination recipients. Hence, absent of second-generation vaccines during the predominant-Omicron period, heterologous boosting using BNT162b2 for inactivated and vectored primary vaccination recipients is preferred.…”

Section: Discussionmentioning

confidence: 99%

Real-world effectiveness of homologous and heterologous BNT162b2, CoronaVac, and AZD1222 booster vaccination against Delta and Omicron SARS-CoV-2 infection

Suah

Tng

Tok

et al. 2022

Emerging Microbes & Infections

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Given emerging evidence of immune escape in the SARS-CoV-2 Omicron viral variant, and its dominance, effectiveness of heterologous and homologous boosting schedules commonly used in low-to-middle income countries needs to be re-evaluated. We conducted a test-negative design using consolidated national administrative data in Malaysia to compare the effectiveness of homologous and heterologous BNT162b2, CoronaVac, and AZD1222 booster vaccination against SARS-CoV-2 infection in predominant-Delta and predominant-Omicron periods. Across both periods, homologous CoronaVac and AZD1222 boosting demonstrated lower effectiveness than heterologous boosting for CoronaVac and AZD1222 primary vaccination recipients and homologous BNT162b2 boosting. Broadly, marginal effectiveness was smaller by 40–50 percentage points in the Omicron period than the Delta period. Without effective and accessible second-generation vaccines, heterologous boosting using BNT162b2 for inactivated and vectored primary vaccination recipients is preferred.

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“…Real-world, observational data can help address the challenges of delivering anti-SARS-CoV-2 vaccinations. In Chile, Canada, Scotland, Qatar and Israel, such studies [12][13][14][15][16][17][18] already demonstrate a high VE against symptomatic disease and fatal outcomes caused by earlier VOCs. However, limitations in resources and surveillance systems mean that there are few large-scale studies using reliable, structured datasets from registries, pharmacy databases, electronic health or insurance claims records.…”

Section: Introductionmentioning

confidence: 99%

Expert review on global real-world vaccine effectiveness against SARS-CoV-2

Chuenkitmongkol¹,

Solante

Burhan

et al. 2022

Expert Review of Vaccines

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IntroductionCOVID-19 vaccines have been highly effective in reducing morbidity and mortality during the pandemic. While primary series vaccination rates are generally high in Southeast Asian (SEA) countries, various factors have limited the rollout and impact of booster doses. Areas coveredWe reviewed 79 studies in the publicly available International Vaccine Access Center (IVAC) VIEW-hub platform on vaccine effectiveness (VE) after primary immunizations with two-dose schedules. VE data were reported for SARS-CoV-2 infection, COVID-19-related hospitalizations and deaths, and strati ed across variants of concern (VOC), age, study design and prior SARS-CoV-2 infection for mRNA vaccines (BNT162b2, mRNA-1273 and combinations of both), vector vaccines (AstraZeneca, AZD1222 "Vaxzevria") and inactivated virus vaccines (CoronaVac). Expert opinionThe most-studied COVID-19 vaccines provide consistently high (>90%) protection against serious clinical outcomes like hospitalizations and deaths, regardless of variant. Additionally, this protection appears equivalent for mRNA vaccines and vector vaccines like AZD1222, as supported by our analysis of local Asian and relevant international data, and by insights from SEA experts. Given the continued impact of COVID-19 hospitalizations and deaths on healthcare systems worldwide, encouraging vaccination strategies that can reduce this burden is more relevant than attempting to prevent broader but milder infections with speci c variants, including Omicron. Article highlights-VE was high and comparable for both AZD1222 and mRNA vaccine types (91%-93%) in protecting against hospitalization and death from COVID-19, regardless of age.-VE against symptomatic infections trended higher (though not signi cantly) for mRNA-based vaccines compared to AZD1222.-Waning of VE since time of vaccination was observed for symptomatic infections but was limited for serious COVID-19 outcomes. A sub-analysis of studies with comparative arms evaluating the VE of different vaccines in the same settings also con rmed these observations for all VOC assessed, with all vaccines conferring a high level of protection against serious outcomes.-For Omicron, there is limited comparative data within the IVAC dataset, however, expert review of emerging data suggests that VE against all outcomes is lower for all COVID-19 vaccines, than for the Delta variant.-Data from the UK indicate that VE improves with a booster dose and that VE continues to be very similar, irrespective of the type of vaccine used.-Importantly, all COVID-19 vaccines evaluated here have favorable bene t/risk pro les.-Although many SEA countries have high rates of primary vaccination, there are still challenges to achieving high booster dose coverage. The results of this analysis suggest that the most effective way to achieve vaccine booster targets, particularly in resource-limited settings, would simply be to consider any vaccines which have good safety and comparable effectiveness pro les, particularly against severe outcomes, and that are accessi...

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Effectiveness of Homologous and Heterologous Booster Shots for an Inactivated SARS-CoV-2 Vaccine: A Large-Scale Observational Study

Cited by 9 publications

References 16 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

Real-world effectiveness of homologous and heterologous BNT162b2, CoronaVac, and AZD1222 booster vaccination against Delta and Omicron SARS-CoV-2 infection

Expert review on global real-world vaccine effectiveness against SARS-CoV-2

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