The effectiveness of COVID-19 vaccines against severe cases and deaths in Brazil from 2021 to 2022: a registry-based study.

Background: Brazil started the COVID-19 mass vaccination in January 2021 with CoronaVac and ChAdOx1, followed by BNT162b2 and Ad26.COV2.S vaccines. By the end of 2021, more than 317 million vaccine doses were administered in the adult population. This study aimed at estimating the effectiveness of the primary series of COVID-19 vaccination and booster shots in protecting against severe cases and deaths in Brazil during the first year of vaccination. Methods: A cohort dataset of over 158 million vaccination and severe cases records linked from official national registries was analyzed via a mixed-effects Poisson model, adjusted for age, state of residence, time after immunization, and calendar time to estimate the absolute vaccine effectiveness of the primary series of vaccination and the relative effectiveness of the booster. The method permitted analysis of effectiveness against hospitalizations and deaths, including in the periods of variant dominance. Findings: Vaccine effectiveness against severe cases and deaths remained over 25% and 50%, respectively, after 19 weeks from primary vaccination of BNT162b2, ChAdOx1, or CoronaVac vaccines. The boosters conferred greater protection than the primary series of vaccination, with heterologous boosters providing marginally greater protection than homologous. The effectiveness against hospitalization during the Omicron dominance in the 60+ years old population started at 61.7% (95% CI, 26.1-86.2) for ChAdOx1, 95.6% (95% CI, 82.4-99.9) for CoronaVac, and 72.3% (95% CI, 51.4-87.4) for the BNT162b2 vaccine. Interpretation: This study provides real-world evidence of the effectiveness of COVID-19 vaccination in Brazil, including during the Omicron wave, demonstrating protection even after waning effectiveness. Comparisons of the effectiveness among different vaccines require caution due to potential bias effects related to age groups, periods in the pandemic, and eventual behavioural changes. Funding: Fundação Oswaldo Cruz (FIOCRUZ), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ), Pan American Health Organization (PAHO), Departamento de Ciência e Tecnologia da Secretaria de Ciência, Tecnologia, Inovação e Insumos Estratégicos em Saúde do Ministério da Saúde do Brasil (DECIT/SCTIE/MS).

Estimated COVID-19 severe cases and deaths averted in the first year of the vaccination campaign in Brazil: A retrospective observational study.

Background: A nationwide Severe Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) vaccination campaign was initiated in Brazil in January 2021 with CoronaVac (Sinovac Biotech) and ChAdOx1 nCoV-19 (AstraZeneca) followed by BNT162b2 mRNA (Pfizer-BioNTech) and Ad26.COV2.S (Johnson & Johnson-Janssen) vaccines. Here we provide estimates of the number of severe cases and deaths due to coronavirus disease (COVID-19) averted during the first year of the mass vaccination campaign in Brazil. Methods: Data on COVID-19 vaccination and COVID-19-related illness and death were obtained from the Brazilian Ministry of Health and used to estimate the direct effects of the vaccination campaign on the number of severe cases and deaths due to COVID-19 occurring between January 17, 2021 and January 31, 2022. To this end, we compared the daily age-specific rates between the unvaccinated population and the "at least partly vaccinated" population (received at least one dose of a two-dose vaccine), as well as other two vaccination subgroups, "fully vaccinated" (completed the one- or two-dose vaccine schedule), and "boosted-vaccinated" (fully vaccinated and recipients of booster dose) populations. Findings: We estimated that 74% (n = 875,846; 95% confidence interval, CI 843,383-915,709) of total expected cases of severe COVID-19 and 82% (n = 303,129; 95% CI 284,019-321,681) of total expected deaths due to COVID-19 were averted in the first year of the national vaccination campaign. The averted burden was heterogeneous between age groups and higher in the more populous states. However, outcome rate differences between vaccinated and unvaccinated groups were higher in the less populated states. Interpretation: The first year of the COVID-19 vaccination program in Brazil saved the lives of at least 303,129 adults. The results highlight the need for future vaccination campaigns, including those required in the current pandemic, to rapidly achieve high uptake, particularly among the elderly and residents of the least populous regions. Funding: Ministry of Health (Brazil).

Controvérsias sobre a ampliação das áreas com vacinação de rotina contra a febre amarela no Brasil / Controversias sobre la ampliación de las áreas con vacunación rutinaria contra la fiebre amarilla en Brasil / Controversies in the expansion of areas with routine yellow fever vaccination in Brazil

Resumo: Febre amarela é uma doença viral potencialmente grave, transmitida por mosquitos Haemagogus, Aedes e Sabethes. A vacinação é a medida mais importante para a sua prevenção e controle. Neste artigo, analisamos as recomendações de vacinação no Brasil, segundo a epidemiologia da doença nas últimas décadas. Considerando a facilidade de deslocamentos de suscetíveis para áreas de risco, e sua tendência de expansão, é provável que eventualmente todo o país tenha de adotar a vacinação rotineira. Porém, no processo decisório de ampliação da população candidata à vacinação, questões relacionadas à segurança vacinal têm sido destacadas. Apresentamos uma análise dos riscos e benefícios da vacinação e das estratégias para o controle da doença e prevenção da sua urbanização nas regiões onde a vacina ainda não é recomendada. Concluímos que a introdução da vacina contra a febre amarela no calendário de vacinação das crianças é uma estratégia proativa, de mais fácil operacionalização, como resposta ao aumento do número de casos de febre amarela silvestre no Brasil e tentativa de prevenção da reurbanização da doença.

Resumen: La fiebre amarilla es una enfermedad viral, potencialmente grave, transmitida por mosquitos Haemagogus, Aedes y Sabethes. La vacunación es la medida más importante para su prevención y control. En este artículo, analizamos las recomendaciones de vacunación en Brasil, según la epidemiología de la enfermedad en las últimas décadas. Considerando la facilidad de los desplazamientos de personas susceptibles hacia zonas de riesgo, y la tendencia de expansión de esta enfermedad, es probable que eventualmente todo el país tenga de adoptar la vacunación rutinaria. No obstante, en el proceso de decisión para la ampliación de la población candidata a la vacunación, se han destacado cuestiones relacionadas con la seguridad de la vacunación. Presentamos un análisis de los riesgos y beneficios de la vacunación y de las estrategias para el control de la enfermedad y prevención de su urbanización en las regiones donde la vacuna todavía no está recomendada. Concluimos que la introducción de la vacuna contra la fiebre amarilla en el calendario de vacunación de los niños es una estrategia proactiva, de más fácil operacionalización, como respuesta al aumento del número de casos de fiebre amarilla silvestre en Brasil, así como una tentativa de prevención frente a la reurbanización de la enfermedad.

Abstract: Yellow fever is a potentially severe viral disease transmitted by mosquitos of the genera Haemagogus, Aedes, and Sabethes. Vaccination is the most important measure for prevention and control of the disease. This article analyzes the immunization guidelines in Brazil based on epidemiology of the disease in recent decades. Considering the ease of human movement into areas at risk of transmission and the tendency for these areas to expand, in time the entire country will probably need to adopt routine vaccination. However, in the decision on expanding the target population for vaccination, vaccine safety issues have been emphasized. We present a risk-benefit analysis of vaccination and strategies for controlling the disease and preventing its urbanization in regions where the vaccine is still not recommended. We conclude that inclusion of the yellow fever vaccine on the childhood immunization schedule is a proactive, easily operationalized strategy as a response to the increase in the number of cases of sylvatic yellow fever in Brazil, and an attempt at preventing re-urbanization of the disease.

Immunogenicity, reactogenicity and consistency of production of a Brazilian combined vaccine against diphtheria, tetanus, pertussis and Haemophilus influenzae type b.

A randomized, double-blinded study evaluating the immunogenicity, safety and consistency of production of a combined diphtheria-tetanus-pertussis-Haemophilus influenzae type b vaccine entirely produced in Brazil by Bio-Manguinhos and Instituto Butantan (DTP/Hib-BM) was undertaken. The reference vaccine had the same DTP vaccine but the Hib component was produced using purified materials supplied by GlaxoSmithKline (DTP/Hib-GSK), which is registered and has supplied the Brazilian National Immunization Program for over more than five years. One thousand infants were recruited for the study and received vaccinations at two, four and six months of age. With respect to immunogenicity, the vaccination protocol was followed in 95.6% and 98.4% of infants in the DTP/Hib-BM and DTP/Hib-GSK groups, respectively. For the Hib component of the study, there was 100% seroprotection (> or =0.15 microg/mL) with all three lots of DTP/Hib-BM and DTP/Hib-GSK. The geometric mean titer (GMT) was 9.3 microg/mL, 10.3 microg/mL and 10.3 microg/mL for lots 1, 2 and 3 of DTP/Hib-BM, respectively, and the GMT was 11.3 g/mL for DTP/Hib-GSK. For diphtheria, tetanus and pertussis, seroprotection was 99.7%, 100% and 99.9%, respectively, for DTP/Hib-BM, three lots altogether and 99.2%, 100% and 100% for DTP/Hib-GSK. GMTs were similar across all lots and vaccines. Adverse events rates were comparable among the vaccine groups. The Brazilian DTP/Hib vaccine demonstrated an immunogenicity and reactogenicity profile similar to that of the reference vaccine.

Immunogenicity, reactogenicity and consistency of production of a Brazilian combined vaccine against diphtheria, tetanus, pertussis and Haemophilus influenzae type b

A randomized, double-blinded study evaluating the immunogenicity, safety and consistency of production of a combined diphtheria-tetanus-pertussis-Haemophilus influenzae type b vaccine entirely produced in Brazil by Bio-Manguinhos and Instituto Butantan (DTP/Hib-BM) was undertaken. The reference vaccine had the same DTP vaccine but the Hib component was produced using purified materials supplied by GlaxoSmithKline (DTP/Hib-GSK), which is registered and has supplied the Brazilian National Immunization Program for over more than five years. One thousand infants were recruited for the study and received vaccinations at two, four and six months of age. With respect to immunogenicity, the vaccination protocol was followed in 95.6 percent and 98.4 percent of infants in the DTP/Hib-BM and DTP/Hib-GSK groups, respectively. For the Hib component of the study, there was 100 percent seroprotection (>0.15 µg/mL) with all three lots of DTP/Hib-BM and DTP/Hib-GSK. The geometric mean titer (GMT) was 9.3 µg/mL, 10.3 µg/mL and 10.3 µg/mL for lots 1, 2 and 3 of DTP/Hib-BM, respectively, and the GMT was 11.3 g/mL for DTP/Hib-GSK. For diphtheria, tetanus and pertussis, seroprotection was 99.7 percent, 100 percent and 99.9 percent, respectively, for DTP/Hib-BM, three lots altogether and 99.2 percent, 100 percent and 100 percent for DTP/Hib-GSK. GMTs were similar across all lots and vaccines. Adverse events rates were comparable among the vaccine groups. The Brazilian DTP/Hib vaccine demonstrated an immunogenicity and reactogenicity profile similar to that of the reference vaccine.