Safety of the Fiocruz ChAdOx COVID-19 vaccine used in a mass vaccination campaign in Botucatu, Brazil

Clemens, Sue Ann Costa; Fortaleza, Carlos Magno Castelo Branco; Crowe, Madeleine; Pollard, Andrew J.; Tasca, Karen Ingrid; Grotto, Rejane Maria Tommasini; Martins, Marcelo R.; Spadaro, André Gasparini; Barretti, Pasqual; Verstraeten, Tom; Clemens, Ralf

doi:10.1016/j.vaccine.2022.08.026

Cited by 3 publications

(2 citation statements)

References 14 publications

(18 reference statements)

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“…We restricted the analysis to those that had symptom onset 2 weeks after each of the mass vaccination campaign dates, to avoid that an increase in testing following COVID-like side effects of the vaccine may bias the VE estimates. This finding is supported by an observed increase in Emergency Room attendance and hospitalizations in the 1 week following each campaign, which was noted in our safety results reported elsewhere ( 13 ).…”

Section: Discussionsupporting

confidence: 91%

Effectiveness of the Fiocruz recombinant ChadOx1-nCoV19 against variants of SARS-CoV-2 in the Municipality of Botucatu-SP

Clemens

Fortaleza

Crowe³

et al. 2022

Front. Public Health

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IntroductionAs the COVID-19 pandemic progresses, rapidly emerging variants of concern raise fears that currently licensed vaccines may have reduced effectiveness against these new strains. In the municipality of Botucatu, São Paulo State, Brazil, a mass vaccination campaign using ChadOx1-nCoV19 was initiated on 16th of May 2021, targeting people 18–60 years old. Two vaccine doses were offered 12 weeks apart, with the second delivered on 8th of August, 2021. This setting offered a unique opportunity to assess the effectiveness of two ChadOx1-nCoV19 doses in a real-life setting.Materials and methodsData on testing, hospitalization, symptoms, demographics, and vaccination were obtained from the Hospital das Clínicas da Faculdade de Medicina de Botucatu. A test-negative study design was employed; whereby the odds of being vaccinated among cases vs controls were calculated to estimate vaccine effectiveness (VE; 1-OR). All individuals aged 18–60 who received a PCR test after the 16th of May and were unvaccinated prior to this date were included in the analysis until the study ended in mid-November 2021.Results77,683 citizens of Botucatu aged 18–60 received the first dose, and 74,051 received a second ChadOx1-nCoV19 dose 12 weeks later for a vaccination coverage of 84.2 and 80.2%, respectively. Of 7.958 eligible PCR tests, 2.109 were positive and 5.849 negative. The VE against any symptomatic infection was estimated at 39.2%, 21 days after dose 1, and 74.5%, 14 days after dose 2. There were no COVID-19-related hospitalizations or deaths among the 74,051 fully vaccinated individuals. The VE against severe disease was estimated at 70.8 and 100% after doses 1 and 2, respectively. 90.5% of all lineages sequenced between doses 1 and 2 (16th of May−7th of August) were of the Gamma variant, while 83.0% were of the Delta variant during the second period after dose 2 (8th of August−18th of November).DiscussionThis observational study found the effectiveness of ChadOx1-nCoV19 to be 74.5% against COVID-19 disease of any severity, comparable to the efficacy observed in clinical trials (81.3% after dose 2), despite the dominance of the Gamma and Delta VoCs. No COVID-19-related hospitalizations or deaths in fully vaccinated individuals were reported.

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Section: Discussionsupporting

confidence: 91%

Effectiveness of the Fiocruz recombinant ChadOx1-nCoV19 against variants of SARS-CoV-2 in the Municipality of Botucatu-SP

Clemens

Fortaleza

Crowe³

et al. 2022

Front. Public Health

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“…The mass vaccination campaign conducted in Botucatu City (on May 16 and Aug 08, 2021) was a success, allowing the immunization of 77,683 and 60,333 inhabitants (first and second dose, respectively) from a total of 92,394 adults (i.e., coverage 84 and 80%), in a record period. This resulted in a drastically reduced number of deaths especially in the pre-omicron period ( 11 , 12 ).…”

Section: Discussionmentioning

confidence: 99%

Dichotomous outcomes vs. survival regression models for identification of predictors of mortality among patients with severe acute respiratory illness during COVID-19 pandemics

Tasca,

Alves,

Grotto

et al. 2023

Front. Public Health

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IntroductionAs the studies predicting mortality in severe acute respiratory illness (SARI) have inferred associations either from dichotomous outcomes or from time-event models, we identified some clinical-epidemiological characteristics and predictors of mortality by comparing and discussing two multivariate models.MethodsTo identify factors associated with death among all SARI hospitalizations occurred in Botucatu (Brazil)/regardless of the infectious agent, and among the COVID-19 subgroup, from March 2020 to 2022, we used a multivariate Poisson regression model with binomial outcomes and Cox proportional hazards (time-event). The performance metrics of both models were also analyzed.ResultsA total of 3,995 hospitalized subjects were included, of whom 1338 (33%) tested positive for SARS-CoV-2. We identified 866 deaths, of which 371 (43%) were due to the COVID-19. In the total number of SARI cases, using both Poisson and Cox models, the predictors of mortality were the presence of neurological diseases, immunosuppression, obesity, older age, and need for invasive ventilation support. However, the Poisson test also revealed that admission to an intensive care unit and the COVID-19 diagnosis were predictors of mortality, with the female gender having a protective effect against death. Likewise, Poisson proved to be more sensitive and specific, and indeed the most suitable model for analyzing risk factors for death in patients with SARI/COVID-19.ConclusionGiven these results and the acute course of SARI and COVID-19, to compare the associations and their different meanings is essential and, therefore, models with dichotomous outcomes are more appropriate than time-to-event/survival approaches.

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Azd-1222

2023

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Safety of the Fiocruz ChAdOx COVID-19 vaccine used in a mass vaccination campaign in Botucatu, Brazil

Cited by 3 publications

References 14 publications

Effectiveness of the Fiocruz recombinant ChadOx1-nCoV19 against variants of SARS-CoV-2 in the Municipality of Botucatu-SP

Effectiveness of the Fiocruz recombinant ChadOx1-nCoV19 against variants of SARS-CoV-2 in the Municipality of Botucatu-SP

Dichotomous outcomes vs. survival regression models for identification of predictors of mortality among patients with severe acute respiratory illness during COVID-19 pandemics

Azd-1222

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