Effectiveness of CoronaVac in the prevention of COVID-19, a test-negative case-control study in Brazil
The present study aimed to evaluate the effectiveness of two doses of CoronaVac in preventing SARS-CoV-2 symptomatic disease with virological confirmation, as well as in the prevention of COVID-19 moderate and severe cases. A test-negative unmatched case-control design was used, in which cases were...
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| Format: | Article |
| Language: | English |
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Elsevier
2024-09-01
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| Series: | Brazilian Journal of Infectious Diseases |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1413867024001399 |
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| author | Expedito J.A. Luna José C. Moraes Manuela A. Roediger Erique J.F.P. Miranda Patrícia E. Braga João I.D. França Pedro H.M. Pacheco Marcos Alves de Lima Lucas Ragiotto Eliana N.C. Barros |
| author_facet | Expedito J.A. Luna José C. Moraes Manuela A. Roediger Erique J.F.P. Miranda Patrícia E. Braga João I.D. França Pedro H.M. Pacheco Marcos Alves de Lima Lucas Ragiotto Eliana N.C. Barros |
| author_sort | Expedito J.A. Luna |
| collection | DOAJ |
| description | The present study aimed to evaluate the effectiveness of two doses of CoronaVac in preventing SARS-CoV-2 symptomatic disease with virological confirmation, as well as in the prevention of COVID-19 moderate and severe cases. A test-negative unmatched case-control design was used, in which cases were patients with suspected COVID-19 (presenting at least two of the following symptoms: fever, chills, sore throat, headache, cough, runny nose, olfactory or taste disorders) with virological confirmation, and controls were those whose SARS-CoV-2 test was negative. As for exposure, participants were classified as unvaccinated, or vaccinated with a complete schedule. Suspected COVID-19 cases were identified from March to November 2021, in two cities located in the State of São Paulo, Brazil. All participants signed the Informed Consent Form before enrollment. RT-PCR results and vaccination data were obtained from the local surveillance systems. Up to two phone calls were made to obtain information on the outcome of the cases. A total of 2981 potential participants were screened for eligibility, of which 2163 were included, being 493 cases and 1670 controls. Vaccination, age, the reported contact with a COVID-19 suspected or confirmed case in the 14 days before symptoms onset, and the educational level were the variables independently associated with the outcome. The adjusted vaccine effectiveness for symptomatic COVID-19 (AVE) was 39.0 % (95 % CI 6.0–60.0 %). The AVE in the prevention of moderate and severe disease was 91.0 % (95 % CI 76.0–97.0 %). Our results were influenced by the waning of the Gamma variant, in the second trimester of 2021, followed by the increase in vaccination coverage, and a drop in the number of cases in the second half of the year. The study demonstrated the high effectiveness of CoronaVac in preventing moderate/severe COVID-19 cases. |
| format | Article |
| id | doaj-art-51dde490bde84c0f90745b91df4b8e65 |
| institution | OA Journals |
| issn | 1413-8670 |
| language | English |
| publishDate | 2024-09-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Brazilian Journal of Infectious Diseases |
| spelling | doaj-art-51dde490bde84c0f90745b91df4b8e652025-08-20T02:11:37ZengElsevierBrazilian Journal of Infectious Diseases1413-86702024-09-0128510385610.1016/j.bjid.2024.103856Effectiveness of CoronaVac in the prevention of COVID-19, a test-negative case-control study in BrazilExpedito J.A. Luna0José C. Moraes1Manuela A. Roediger2Erique J.F.P. Miranda3Patrícia E. Braga4João I.D. França5Pedro H.M. Pacheco6Marcos Alves de Lima7Lucas Ragiotto8Eliana N.C. Barros9Universidade de São Paulo, Faculdade de Medicina, São Paulo, SP, Brazil; Corresponding author.Faculdade de Ciências Médicas da Santa Casa, São Paulo, SP, BrazilInstituto Butantan, São Paulo, SP, BrazilInstituto Butantan, São Paulo, SP, BrazilInstituto Butantan, São Paulo, SP, BrazilInstituto Butantan, São Paulo, SP, BrazilInstituto Butantan, São Paulo, SP, BrazilInstituto Butantan, São Paulo, SP, BrazilInstituto Butantan, São Paulo, SP, BrazilInstituto Butantan, São Paulo, SP, BrazilThe present study aimed to evaluate the effectiveness of two doses of CoronaVac in preventing SARS-CoV-2 symptomatic disease with virological confirmation, as well as in the prevention of COVID-19 moderate and severe cases. A test-negative unmatched case-control design was used, in which cases were patients with suspected COVID-19 (presenting at least two of the following symptoms: fever, chills, sore throat, headache, cough, runny nose, olfactory or taste disorders) with virological confirmation, and controls were those whose SARS-CoV-2 test was negative. As for exposure, participants were classified as unvaccinated, or vaccinated with a complete schedule. Suspected COVID-19 cases were identified from March to November 2021, in two cities located in the State of São Paulo, Brazil. All participants signed the Informed Consent Form before enrollment. RT-PCR results and vaccination data were obtained from the local surveillance systems. Up to two phone calls were made to obtain information on the outcome of the cases. A total of 2981 potential participants were screened for eligibility, of which 2163 were included, being 493 cases and 1670 controls. Vaccination, age, the reported contact with a COVID-19 suspected or confirmed case in the 14 days before symptoms onset, and the educational level were the variables independently associated with the outcome. The adjusted vaccine effectiveness for symptomatic COVID-19 (AVE) was 39.0 % (95 % CI 6.0–60.0 %). The AVE in the prevention of moderate and severe disease was 91.0 % (95 % CI 76.0–97.0 %). Our results were influenced by the waning of the Gamma variant, in the second trimester of 2021, followed by the increase in vaccination coverage, and a drop in the number of cases in the second half of the year. The study demonstrated the high effectiveness of CoronaVac in preventing moderate/severe COVID-19 cases.http://www.sciencedirect.com/science/article/pii/S1413867024001399SARS-CoV2Inactivated vaccinesEffectivenessTest-negativeCase-control studyBrazil |
| spellingShingle | Expedito J.A. Luna José C. Moraes Manuela A. Roediger Erique J.F.P. Miranda Patrícia E. Braga João I.D. França Pedro H.M. Pacheco Marcos Alves de Lima Lucas Ragiotto Eliana N.C. Barros Effectiveness of CoronaVac in the prevention of COVID-19, a test-negative case-control study in Brazil Brazilian Journal of Infectious Diseases SARS-CoV2 Inactivated vaccines Effectiveness Test-negative Case-control study Brazil |
| title | Effectiveness of CoronaVac in the prevention of COVID-19, a test-negative case-control study in Brazil |
| title_full | Effectiveness of CoronaVac in the prevention of COVID-19, a test-negative case-control study in Brazil |
| title_fullStr | Effectiveness of CoronaVac in the prevention of COVID-19, a test-negative case-control study in Brazil |
| title_full_unstemmed | Effectiveness of CoronaVac in the prevention of COVID-19, a test-negative case-control study in Brazil |
| title_short | Effectiveness of CoronaVac in the prevention of COVID-19, a test-negative case-control study in Brazil |
| title_sort | effectiveness of coronavac in the prevention of covid 19 a test negative case control study in brazil |
| topic | SARS-CoV2 Inactivated vaccines Effectiveness Test-negative Case-control study Brazil |
| url | http://www.sciencedirect.com/science/article/pii/S1413867024001399 |
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