Dataset Information

CoronaVac vaccine is effective in preventing symptomatic and severe COVID-19 in pregnant women in Brazil: a test-negative case-control study.

ABSTRACT:

Background

More doses of CoronaVac have been administered worldwide than any other COVID-19 vaccine. However, the effectiveness of COVID-19 inactivated vaccines in pregnant women is still unknown. We estimated the vaccine effectiveness (VE) of CoronaVac against symptomatic and severe COVID-19 in pregnant women in Brazil.

Methods

We conducted a test-negative design study in all pregnant women aged 18-49 years with COVID-19-related symptoms in Brazil from March 15, 2021, to October 03, 2021, linking records of negative and positive SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR) tests to national vaccination records. We also linked records of test-positive cases with notifications of severe, hospitalised or fatal COVID-19. Using logistic regression, we estimated the adjusted odds ratio and VE against symptomatic COVID-19 and against severe COVID-19 by comparing vaccine status in test-negative subjects to test-positive symptomatic cases and severe cases.

Results

Of the 19,838 tested pregnant women, 7424 (37.4%) tested positive for COVID-19 and 588 (7.9%) had severe disease. Only 83% of pregnant women who received the first dose of CoronaVac completed the vaccination scheme. A single dose of the CoronaVac vaccine was not effective at preventing symptomatic COVID-19. The effectiveness of two doses of CoronaVac was 41% (95% CI 27.1-52.2) against symptomatic COVID-19 and 85% (95% CI 59.5-94.8) against severe COVID-19.

Conclusions

A complete regimen of CoronaVac in pregnant women was effective in preventing symptomatic COVID-19 and highly effective against severe illness in a setting that combined high disease burden and marked COVID-19-related maternal deaths.

SUBMITTER: Paixao ES

PROVIDER: S-EPMC8979723 | biostudies-literature | 2022 Apr

REPOSITORIES: biostudies-literature

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Publications

CoronaVac vaccine is effective in preventing symptomatic and severe COVID-19 in pregnant women in Brazil: a test-negative case-control study.

Paixao Enny S ES Wong Kerry L M KLM Alves Flavia Jôse Oliveira FJO de Araújo Oliveira Vinicius V Cerqueira-Silva Thiago T Júnior Juracy Bertoldo JB Machado Tales Mota TM Junior Elzo Pereira Pinto EPP Boaventura Viviane S VS Penna Gerson O GO Werneck Guilherme Loureiro GL Rodrigues Laura C LC Pearce Neil N Barreto Mauricio L ML Barral-Netto Manoel M

BMC medicine 20220405 1

<h4>Background</h4>More doses of CoronaVac have been administered worldwide than any other COVID-19 vaccine. However, the effectiveness of COVID-19 inactivated vaccines in pregnant women is still unknown. We estimated the vaccine effectiveness (VE) of CoronaVac against symptomatic and severe COVID-19 in pregnant women in Brazil.<h4>Methods</h4>We conducted a test-negative design study in all pregnant women aged 18-49 years with COVID-19-related symptoms in Brazil from March 15, 2021, to October ...[more]

PMID: 35379250

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Project description:BackgroundLittle is known about vaccine effectiveness over time among adolescents, especially against the SARS-CoV-2 omicron (B.1.1.529) variant. This study assessed the associations between time since two-dose vaccination with BNT162b2 and the occurrence of symptomatic SARS-CoV-2 infection and severe COVID-19 among adolescents in Brazil and Scotland.MethodsWe did test-negative, case-control studies in adolescents aged 12-17 years with COVID-19-related symptoms in Brazil and Scotland. We linked records of SARS-CoV-2 RT-PCR and antigen tests to national vaccination and clinical records. We excluded tests from individuals who did not have symptoms, were vaccinated before the start of the national vaccination programme, received vaccines other than BNT162b2 or a SARS-CoV-2 booster dose of any kind, or had an interval between their first and second dose of fewer than 21 days. Additionally, we excluded negative SARS-CoV-2 tests recorded within 14 days of a previous negative test, negative tests recorded within 7 days after a positive test, any test done within 90 days after a positive test, and tests with missing sex and location information. Cases (SARS-CoV-2 test-positive adolescents) and controls (test-negative adolescents) were drawn from a sample of individuals in whom tests were collected within 10 days of symptom onset. We estimated the adjusted odds ratio and vaccine effectiveness against symptomatic COVID-19 for both countries and against severe COVID-19 (hospitalisation or death) for Brazil across fortnightly periods.FindingsWe analysed 503 776 tests from 2 948 538 adolescents in Brazil between Sept 2, 2021, and April 19, 2022, and 127 168 tests from 404 673 adolescents in Scotland between Aug 6, 2021, and April 19, 2022. Vaccine effectiveness peaked at 14-27 days after the second dose in both countries during both waves, and was significantly lower against symptomatic infection during the omicron-dominant period in Brazil (64·7% [95% CI 63·0-66·3]) and in Scotland (82·6% [80·6-84·5]), than it was in the delta-dominant period (80·7% [95% CI 77·8-83·3] in Brazil and 92·8% [85·7-96·4] in Scotland). Vaccine efficacy started to decline from 27 days after the second dose for both countries, reducing to 5·9% (95% CI 2·2-9·4) in Brazil and 50·6% (42·7-57·4) in Scotland at 98 days or more during the omicron-dominant period. In Brazil, protection against severe disease remained above 80% from 28 days after the second dose and was 82·7% (95% CI 68·8-90·4) at 98 days or more after receiving the second dose.InterpretationWe found waning vaccine protection of BNT162b2 against symptomatic COVID-19 infection among adolescents in Brazil and Scotland from 27 days after the second dose. However, protection against severe COVID-19 outcomes remained high at 98 days or more after the second dose in the omicron-dominant period. Booster doses for adolescents need to be considered.FundingUK Research and Innovation (Medical Research Council), Scottish Government, Health Data Research UK BREATHE Hub, Fiocruz, Fazer o Bem Faz Bem programme, Brazilian National Research Council, and Wellcome Trust.TranslationFor the Portuguese translation of the abstract see Supplementary Materials section.

Project description:ObjectiveTo estimate the effectiveness of the inactivated whole virus vaccine, CoronaVac (Sinovac Biotech), against symptomatic covid-19 in the elderly population of São Paulo state, Brazil during widespread circulation of the gamma variant.DesignTest negative case-control study.SettingCommunity testing for covid-19 in São Paulo state, Brazil.Participants43 774 adults aged ≥70 years who were residents of São Paulo state and underwent reverse transcription polymerase chain reaction (RT-PCR) testing for SARS-CoV-2 from 17 January to 29 April 2021. 26 433 cases with symptomatic covid-19 and 17 622 test negative controls with covid-19 symptoms were formed into 13 283 matched sets, one case with to up to five controls, according to age, sex, self-reported race, municipality of residence, previous covid-19 status, and date of RT-PCR test (±3 days).InterventionVaccination with a two dose regimen of CoronaVac.Main outcome measuresRT-PCR confirmed symptomatic covid-19 and associated hospital admissions and deaths.ResultsAdjusted vaccine effectiveness against symptomatic covid-19 was 24.7% (95% confidence interval 14.7% to 33.4%) at 0-13 days and 46.8% (38.7% to 53.8%) at ≥14 days after the second dose. Adjusted vaccine effectiveness against hospital admissions was 55.5% (46.5% to 62.9%) and against deaths was 61.2% (48.9% to 70.5%) at ≥14 days after the second dose. Vaccine effectiveness ≥14 days after the second dose was highest for the youngest age group (70-74 years)-59.0% (43.7% to 70.2%) against symptomatic disease, 77.6% (62.5% to 86.7%) against hospital admissions, and 83.9% (59.2% to 93.7%) against deaths-and declined with increasing age.ConclusionsVaccination with CoronaVac was associated with a reduction in symptomatic covid-19, hospital admissions, and deaths in adults aged ≥70 years in a setting with extensive transmission of the gamma variant. Vaccine protection was, however, low until completion of the two dose regimen, and vaccine effectiveness was observe to decline with increasing age among this elderly population.

Project description:ObjectiveTo estimate real world vaccine effectiveness against symptomatic disease and hospital admission with the delta and omicron variants of the SARS-CoV-2 virus in pregnant individuals, and to estimate the protection conferred by previous infection and maternal vaccination in their infants.DesignTest negative case-control study.SettingCommunity and hospital testing for covid-19, in England, 26 April 2021 to 9 January 2022 (delta variant period) and 29 November 2021 to 31 March 2022 (omicron variant period). Testing data were linked to Hospital Episode Statistics and Maternal Services Data Set (for data on pregnant individuals and infants), National Immunisation Management System (for covid-19 vaccinations), and Secondary Uses Service (for hospital admissions).Participants35 206 negative and 16 693 positive eligible test results in the delta variant period from pregnant individuals with symptoms of infection, aged 16-55 years, whose pregnancy ended in 2021, and 5974 negative and 4715 positive eligible test results in the omicron variant period. For infants born in 2021, 23 053 negative and 2924 positive eligible test results in the delta variant period and 13 908 negative and 5669 positive test results from infants in the omicron period.Main outcome measuresVaccine effectiveness against symptomatic disease and hospital admission with the delta and omicron variants of the SARS-CoV-2 virus in pregnant women. Also, effectiveness of maternal vaccination and the protection conferred by previous infection in mothers in preventing symptomatic disease and hospital admission in their infants in the first six months of life. Symptomatic SARS-CoV-2 infection was confirmed by a positive polymerase chain reaction test result.ResultsVaccine effectiveness against symptomatic disease (delta and omicron infection) and against hospital admission (delta infection only) in pregnant individuals was high, as seen in the general population. A booster dose of vaccine gave sustained protection, with no evidence of waning up to 15 weeks after vaccination. Vaccine effectiveness against symptomatic disease peaked at 98.4% (95% confidence interval (CI) 88.4% to 99.8%) and 80.1% (73.8% to 84.9%) against the delta and omicron variants, respectively, after the booster dose of vaccine. Vaccine effectiveness after a two dose primary schedule against hospital admission with delta infection peaked at 92.7% (95% CI 79.9% to 97.4%) in pregnant individuals. Maternal vaccination during and after pregnancy also provided sustained protection from symptomatic disease and hospital admission after delta and omicron infection in infants aged up to six months, with the highest protection seen when maternal vaccination occurred during later pregnancy. The effectiveness of two maternal doses when the last dose was given in the third trimester was 86.5% (95% CI 81.9% to 90.0%) and 56.6% (46.7% to 64.6%) against symptomatic disease with delta and omicron infection, respectively, in infants, and effectiveness against hospital admission was 94.7% (78.2% to 98.7%) and 78.7% (58.2% to 89.1%), respectively. Previous infection with wild-type, alpha, and delta variants of the SARS-CoV-2 virus in pregnant individuals was more protective against mild and severe delta infection than omicron infection in their infants.ConclusionsThe results of this study indicated that maternal vaccination prevented mild and severe disease in pregnant individuals and their infants for up to six months after birth. The findings support the promotion of both primary and booster vaccination for pregnant individuals to protect themselves and their infants.

Dataset Information

CoronaVac vaccine is effective in preventing symptomatic and severe COVID-19 in pregnant women in Brazil: a test-negative case-control study.

Background

Methods

Results

Conclusions

Publications

CoronaVac vaccine is effective in preventing symptomatic and severe COVID-19 in pregnant women in Brazil: a test-negative case-control study.

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