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Projeto S: A Stepped-Wedge Randomized Trial to Assess CoronaVac Effectiveness in Serrana, Brazil

31 Pages Posted: 29 Nov 2021

See all articles by Marcos C. Borges

Marcos C. Borges

University of São Paulo (USP) - Ribeirão Preto Medical School

Ricardo Palacios

Instituto Butantan

Hugo Alberto Brango

Instituto Butantan

Mônica Tilli Reis Pessoa Conde

Instituto Butantan

Elizabeth González Patiño

Instituto Butantan

Ana Paula Batista

Instituto Butantan

Barbara Marques Coutinho

Serrana State Hospital

Gilberto Guedes Padua

Instituto Butantan

Glenda Renata Moraes

Serrana State Hospital - Health Department

Gustavo Jardim Volpe

Serrana State Hospital

Joane Prado Santos

Instituto Butantan

Natasha Nicos Ferreira

Serrana State Hospital

Pedro Manuel Marques Garibaldi

Serrana State Hospital

Ricardo Haddad

Instituto Butantan

Roberta Oliveira Piorelli

Instituto Butantan

Sandra Coccuzzo Sampaio Vessoni

Instituto Butantan

Simone Kashima Haddad

University of São Paulo (USP) - Ribeirão Preto Medical School

Benedito Antonio Lopes da Fonseca

University of São Paulo (USP) - Ribeirão Preto Medical School

Rodrigo Tocantins Calado

University of São Paulo (USP) - Ribeirão Preto Medical School

Dimas Tadeu Covas

University of São Paulo (USP) - Ribeirão Preto Medical School

More...

Abstract

Background: A stepped-wedge trial is an approach for assessing vaccine effectiveness in the real world. By the end of the study, all participants could receive the intervention, eliminating the ethical dilemma of placebo, especially during a pandemic.

Methods: We evaluated the effectiveness of CoronaVac in Serrana, Brazil, amid an uncontrolled community Covid-19 epidemic using a stepped-wedge randomized trial. The city was separated into 25 subareas, divided into four groups, and randomized to receive CoronaVac in a two-dose scheme with a four-week interval. Intervention was initiated in each group with a one-week interval. The primary endpoint was the incidence of symptomatic cases in fully immunized individuals. The secondary endpoints were Covid-19-related hospitalizations and deaths and incidence according to immunization coverage.

Findings: The study occurred during epidemiological weeks 6 to 19 in 2021. Up to 27,406 participants received the first dose of the study vaccine, corresponding to 81·3% of the adults and 60·9% of the urban population. Among fully immunized individuals, the vaccine effectiveness was 80·5 (95% CI, 75·1 to 84·7) for preventing symptomatic Covid-19 cases, 95% (95% CI, 86·9 to 98·1) and 94·9% (95% CI, 76·4 to 98·9) for preventing Covid-19-related hospitalizations and deaths, respectively. There was a significant indirect protective effect in unvaccinated people when 52% of the adult population was fully vaccinated. The Gamma variant was dominant during the study.

Interpretation: CoronaVac effectively prevented symptomatic Covid-19 cases and protected against severe disease and death during Gamma variant circulation. Unvaccinated individuals benefited from high vaccine coverage levels.

Trial Registration: This study was registered with (ClinicalTrials.gov Identifier, NCT04747821)

Funding: Fundação Butantan and São Paulo Research Foundation (FAPESP).

Declaration of Interest: MCB, BMC, GJV, NNF, PMMG, RH, BALF, and RTC received research funding from Butantan Institute during the conduct of this study. RP, MTRPC, APB, JPS, and ROP were employees of Butantan Institute during the conduct of this study. HAB, EGP, GGP, SCSV and DC are employees of Butantan Institute. All other authors declare no competing interests

Ethical Approval: The study was reviewed and approved by the Ethics Committee of the Clinical Hospital, Ribeirão Preto Medical School, University of São Paulo (CAAE 42390621.1.0000.5440).

Keywords: COVID-19, Vaccines, Immunity, Herd

Suggested Citation

Borges, Marcos C. and Palacios, Ricardo and Brango, Hugo Alberto and Conde, Mônica Tilli Reis Pessoa and Patiño, Elizabeth González and Batista, Ana Paula and Coutinho, Barbara Marques and Padua, Gilberto Guedes and Moraes, Glenda Renata and Volpe, Gustavo Jardim and Santos, Joane Prado and Ferreira, Natasha Nicos and Garibaldi, Pedro Manuel Marques and Haddad, Ricardo and Piorelli, Roberta Oliveira and Vessoni, Sandra Coccuzzo Sampaio and Haddad, Simone Kashima and Fonseca, Benedito Antonio Lopes da and Calado, Rodrigo Tocantins and Covas, Dimas Tadeu, Projeto S: A Stepped-Wedge Randomized Trial to Assess CoronaVac Effectiveness in Serrana, Brazil. Available at SSRN: https://ssrn.com/abstract=3973422 or http://dx.doi.org/10.2139/ssrn.3973422

Marcos C. Borges (Contact Author)

University of São Paulo (USP) - Ribeirão Preto Medical School ( email )

Rua Luciano Gualberto, 315
São Paulo
Brazil

Ricardo Palacios

Instituto Butantan ( email )

Avenida Vital Brasil, 1500
Sao Paulo, SP 05503-900
Brazil

Hugo Alberto Brango

Instituto Butantan ( email )

Avenida Vital Brasil, 1500
Sao Paulo, SP 05503-900
Brazil

Mônica Tilli Reis Pessoa Conde

Instituto Butantan ( email )

Avenida Vital Brasil, 1500
Sao Paulo, SP 05503-900
Brazil

Elizabeth González Patiño

Instituto Butantan ( email )

Avenida Vital Brasil, 1500
Sao Paulo, SP 05503-900
Brazil

Ana Paula Batista

Instituto Butantan ( email )

Avenida Vital Brasil, 1500
Sao Paulo, SP 05503-900
Brazil

Barbara Marques Coutinho

Serrana State Hospital ( email )

Sao Paulo
Brazil

Gilberto Guedes Padua

Instituto Butantan ( email )

Avenida Vital Brasil, 1500
Sao Paulo, SP 05503-900
Brazil

Glenda Renata Moraes

Serrana State Hospital - Health Department ( email )

Sao Paulo
Brazil

Gustavo Jardim Volpe

Serrana State Hospital ( email )

Sao Paulo
Brazil

Joane Prado Santos

Instituto Butantan ( email )

Avenida Vital Brasil, 1500
Sao Paulo, SP 05503-900
Brazil

Natasha Nicos Ferreira

Serrana State Hospital ( email )

Sao Paulo
Brazil

Pedro Manuel Marques Garibaldi

Serrana State Hospital ( email )

Sao Paulo
Brazil

Ricardo Haddad

Instituto Butantan ( email )

Avenida Vital Brasil, 1500
Sao Paulo, SP 05503-900
Brazil

Roberta Oliveira Piorelli

Instituto Butantan ( email )

Avenida Vital Brasil, 1500
Sao Paulo, SP 05503-900
Brazil

Sandra Coccuzzo Sampaio Vessoni

Instituto Butantan ( email )

Avenida Vital Brasil, 1500
Sao Paulo, SP 05503-900
Brazil

Simone Kashima Haddad

University of São Paulo (USP) - Ribeirão Preto Medical School ( email )

Rua Luciano Gualberto, 315
São Paulo
Brazil

Benedito Antonio Lopes da Fonseca

University of São Paulo (USP) - Ribeirão Preto Medical School ( email )

Rua Luciano Gualberto, 315
São Paulo
Brazil

Rodrigo Tocantins Calado

University of São Paulo (USP) - Ribeirão Preto Medical School ( email )

Rua Luciano Gualberto, 315
São Paulo
Brazil

Dimas Tadeu Covas

University of São Paulo (USP) - Ribeirão Preto Medical School ( email )

Rua Luciano Gualberto, 315
São Paulo
Brazil

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