Backdrop to the development of Brazil's national COVID-19 immunization plan. / Contexto de elaboração do Plano de Imunização contra COVID-19 no Brasil.

The process of developing Brazil's COVID-19 immunization plan began belatedly and involved a number of experts, including a technical group responsible for defining priority groups for vaccination. This process was permeated by contradictions between the government and researchers. Finally, on 20 January 2021, the government published an updated version of the plan, which remains limited in scope.

O processo de elaboração do Plano de Imunização contra Covid-19 no Brasil se iniciou tardiamente e contou com a participação de especialistas incluindo o grupo técnico responsável pela definição de grupos prioritários para a vacinação. Este processo foi permeado de indefinições entre o Governo Federal e pesquisadores e, finalmente, no dia 20 de janeiro de 2021 foi divulgada a versão atualizada do Plano ainda incipiente no que tange a sua abrangência.

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 10.13039/501100006507Fundação Oswaldo Cruz (FIOCRUZ), Conselho Nacional de Desenvolvimento Científico e Tecnológico (10.13039/501100003593CNPq), 10.13039/501100004586Fundação de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ), 10.13039/100011893Pan 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).

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).

Trends in the prevalence of COVID-19 infection in Rio Grande do Sul, Brazil: repeated serological surveys. / Evolução da prevalência de infecção por COVID-19 no Rio Grande do Sul, Brasil: inquéritos sorológicos seriados.

COVID-19, the disease produced by the virus SARS-CoV-2, has spread quickly throughout the world, leading the World Health Organization to first classify it as an international health emergency and, subsequently, declaring it pandemic. The number of confirmed cases, as April 11, surpassed 1,700,000, but this figure does not reflect the prevalence of COVID-19 in the population as, in many countries, tests are almost exclusively performed in people with symptoms, particularly severe cases. To properly assess the magnitude of the problem and to contribute to the design of evidence-based policies for fighting COVID-19, one must accurately estimate the population prevalence of infection. Our study is aimed at estimating the prevalence of infected individuals in the state of Rio Grande do Sul, Brazil, to document how fast the infection spreads, and to estimate the proportion of infected persons who present or presented symptoms, as well as the proportion of asymptomatic infections. Four repeated serological surveys will be conducted in probability samples of nine sentinel cities every two weeks. Tests will be performed in 4,500 participants in each survey, totaling18,000 interviews. Interviews and tests will be conducted at the participants' household. A rapid test for the detection of antibodies will be used; the test was validated prior to the beginning of the fieldwork.

A COVID-19 é uma doença produzida pelo vírus SARS-CoV-2. Esse vírus se espalhou rapidamente pelo mundo, o que levou a Organização Mundial da Saúde a classificar a COVID-19 como uma emergência de saúde internacional e, posteriormente, a declará-la uma pandemia. O número de casos confirmados, no dia 11 de abril de 2020, já passa de 1.700.000, porém esses dados não refletem a real prevalência de COVID-19 na população, visto que, em muitos países, os testes são quase que exclusivamente realizados em pessoas com sintomas, especialmente os mais graves. Para definir políticas de enfrentamento, é essencial dispor de dados sobre a prevalência real de infecção na população. Este estudo tem por objetivos avaliar a proporção de indivíduos já infectados pelo SARS-CoV-2 no Rio Grande do Sul, Brasil, analisar a velocidade de expansão da infecção e estimar o percentual de infectados com e sem sintomas. Serão realizados quatro inquéritos sorológicos repetidos a cada 15 dias, com amostragem probabilística de nove cidades sentinela, em todas as sub-regiões do Estado. As entrevistas e testes ocorrerão no âmbito domiciliar. Serão utilizados testes rápidos para detecção de anticorpos, validados previamente ao início da coleta de dados.

Optimized delay of the second COVID-19 vaccine dose reduces ICU admissions.

Slower than anticipated, COVID-19 vaccine production and distribution have impaired efforts to curtail the current pandemic. The standard administration schedule for most COVID-19 vaccines currently approved is two doses administered 3 to 4 wk apart. To increase the number of individuals with partial protection, some governments are considering delaying the second vaccine dose. However, the delay duration must take into account crucial factors, such as the degree of protection conferred by a single dose, the anticipated vaccine supply pipeline, and the potential emergence of more virulent COVID-19 variants. To help guide decision-making, we propose here an optimization model based on extended susceptible, exposed, infectious, and removed (SEIR) dynamics that determines the optimal delay duration between the first and second COVID-19 vaccine doses. The model assumes lenient social distancing and uses intensive care unit (ICU) admission as a key metric while selecting the optimal duration between doses vs. the standard 4-wk delay. While epistemic uncertainties apply to the interpretation of simulation outputs, we found that the delay is dependent on the vaccine mechanism of action and first-dose efficacy. For infection-blocking vaccines with first-dose efficacy ≥50%, the model predicts that the second dose can be delayed by ≥8 wk (half of the maximal delay), whereas for symptom-alleviating vaccines, the same delay is recommended only if the first-dose efficacy is ≥70%. Our model predicts that a 12-wk second-dose delay of an infection-blocking vaccine with a first-dose efficacy ≥70% could reduce ICU admissions by 400 people per million over 200 d.

EPICOVID19 protocol: repeated serological surveys on SARS-CoV-2 antibodies in Brazil

The first case of COVID-19 was reported in China in December 2019, and, as the virus has spread worldwide, the World Health Organization declared it a pandemic. Estimates on the number of COVID-19 cases do not reflect it real magnitude as testing is limited. Population based data on the proportion of the population with antibodies is relevant for planning public health policies. We aim to assess the prevalence of SARS-CoV-2 antibodies, presence of signs and symptoms of COVID-19, and adherence to isolation measures. A random sample comprising 133 sentinel cities from all states of the country will be selected. Three serological surveys, three weeks apart, will be conducted. The most populous municipality in each intermediate region of the country, defined by the Brazilian Institute of Geography and Statistics, was chosen as sentinel city. In each city, 25 census tracts will be selected, and 10 households will be systematically sampled in each tract, totaling 33,250 participants. In each household, one inhabitant will be randomly selected to be interviewed and tested for antibodies against SARS-CoV-2, using WONDFO SARS-CoV-2 Antibody Test. By evaluating a representative sample of Brazilian sentinel sites, this study will provide essential information for the design of health policies. Resumo O COVID-19 é causado pelo vírus SARS-CoV-2, sendo o primeiro caso relatado na China em dezembro de 2019. O vírus se espalhou pelo mundo, levando a Organização Mundial da Saúde a declarar uma pandemia. As estimativas do número de casos de COVID-19 não refletem sua magnitude real, pois os testes são limitados em muitos países. Dados populacionais sobre a proporção da população com anticorpos são relevantes para o planejamento de políticas públicas de saúde. Nosso objetivo é avaliar a prevalência de anticorpos SARS-CoV-2, a presença de sinais e de sintomas de COVID-19 e a adesão a medidas de isolamento. Uma amostra aleatória composta por 133 cidades sentinelas de todos os estados do país será selecionada. Serão realizados três levantamentos sorológicos, com três semanas de intervalo. Em cada cidade, serão selecionados 25 setores censitários e 10 famílias serão amostradas aleatoriamente em cada setor. Em cada domicílio, um habitante será selecionado aleatoriamente para ser entrevistado e testado para anticorpos contra SARS-CoV-2, usando o Teste de Anticorpo WONDFO SARS-CoV-2, que foi validado antes do trabalho de campo. Ao avaliar uma amostra representativa dos locais sentinela ao longo do tempo, este estudo fornecerá informações essenciais para o desenho de políticas de saúde.

EPICOVID19 protocol: repeated serological surveys on SARS-CoV-2 antibodies in Brazil

The first case of COVID-19 was reported in China in December 2019, and, as the virus has spread worldwide, the World Health Organization declared it a pandemic. Estimates on the number of COVID-19 cases do not reflect it real magnitude as testing is limited. Population based data on the proportion of the population with antibodies is relevant for planning public health policies. We aim to assess the prevalence of SARS-CoV-2 antibodies, presence of signs and symptoms of COVID-19, and adherence to isolation measures. A random sample comprising 133 sentinel cities from all states of the country will be selected. Three serological surveys, three weeks apart, will be conducted. The most populous municipality in each intermediate region of the country, defined by the Brazilian Institute of Geography and Statistics, was chosen as sentinel city. In each city, 25 census tracts will be selected, and 10 households will be systematically sampled in each tract, totaling 33,250 participants. In each household, one inhabitant will be randomly selected to be interviewed and tested for antibodies against SARS-CoV-2, using WONDFO SARS-CoV-2 Antibody Test. By evaluating a representative sample of Brazilian sentinel sites, this study will provide essential information for the design of health policies. Resumo O COVID-19 é causado pelo vírus SARS-CoV-2, sendo o primeiro caso relatado na China em dezembro de 2019. O vírus se espalhou pelo mundo, levando a Organização Mundial da Saúde a declarar uma pandemia. As estimativas do número de casos de COVID-19 não refletem sua magnitude real, pois os testes são limitados em muitos países. Dados populacionais sobre a proporção da população com anticorpos são relevantes para o planejamento de políticas públicas de saúde. Nosso objetivo é avaliar a prevalência de anticorpos SARS-CoV-2, a presença de sinais e de sintomas de COVID-19 e a adesão a medidas de isolamento. Uma amostra aleatória composta por 133 cidades sentinelas de todos os estados do país será selecionada. Serão realizados três levantamentos sorológicos, com três semanas de intervalo. Em cada cidade, serão selecionados 25 setores censitários e 10 famílias serão amostradas aleatoriamente em cada setor. Em cada domicílio, um habitante será selecionado aleatoriamente para ser entrevistado e testado para anticorpos contra SARS-CoV-2, usando o Teste de Anticorpo WONDFO SARS-CoV-2, que foi validado antes do trabalho de campo. Ao avaliar uma amostra representativa dos locais sentinela ao longo do tempo, este estudo fornecerá informações essenciais para o desenho de políticas de saúde.

EPICOVID19 protocol: repeated serological surveys on SARS-CoV-2 antibodies in Brazil.

The first case of COVID-19 was reported in China in December 2019, and, as the virus has spread worldwide, the World Health Organization declared it a pandemic. Estimates on the number of COVID-19 cases do not reflect it real magnitude as testing is limited. Population based data on the proportion of the population with antibodies is relevant for planning public health policies. We aim to assess the prevalence of SARS-CoV-2 antibodies, presence of signs and symptoms of COVID-19, and adherence to isolation measures. A random sample comprising 133 sentinel cities from all states of the country will be selected. Three serological surveys, three weeks apart, will be conducted. The most populous municipality in each intermediate region of the country, defined by the Brazilian Institute of Geography and Statistics, was chosen as sentinel city. In each city, 25 census tracts will be selected, and 10 households will be systematically sampled in each tract, totaling 33,250 participants. In each household, one inhabitant will be randomly selected to be interviewed and tested for antibodies against SARS-CoV-2, using WONDFO SARS-CoV-2 Antibody Test. By evaluating a representative sample of Brazilian sentinel sites, this study will provide essential information for the design of health policies.

Two complementary model-based methods for calculating the risk of international spreading of a novel virus from the outbreak epicentre. The case of COVID-19.

We present two complementary model-based methods for calculating the risk of international spread of the novel coronavirus SARS-CoV-2 from the outbreak epicentre. One model aims to calculate the number of cases that would be exported from an endemic country to disease-free regions by travellers. The second model calculates the probability that an infected traveller will generate at least one secondary autochthonous case in the visited country. Although this paper focuses on the data from China, our methods can be adapted to calculate the risk of importation and subsequent outbreaks. We found an average R0 = 5.31 (ranging from 4.08 to 7.91) and a risk of spreading of 0.75 latent individuals per 1000 travellers. In addition, one infective traveller would be able to generate at least one secondary autochthonous case in the visited country with a probability of 23%.

Risk of the Brazilian health care system over 5572 municipalities to exceed health care capacity due to the 2019 novel coronavirus (COVID-19).

The spread of the 2019 novel coronavirus (COVID-19) has challenged governments to develop public policies to reduce the load of the COVID-19 on health care systems, which is commonly referred to as "flattening the curve". This study aims to address this issue by proposing a spatial multicriteria approach to estimate the risk of the Brazilian health care system, by municipality, to exceed the health care capacity because of an influx of patients infected with the COVID-19. We estimated this risk for 5572 municipalities in Brazil using a combination of a multicriteria decision-making approach with spatial analysis to estimate the exceedance risk, and then, we examined the risk variation by designing 5 control intervention scenarios (3 scenarios representing reduction on social contacts, and 2 scenarios representing investment on health care system). For the baseline scenario using an average infection rate across Brazil, we estimated a mean Hospital Bed Capacity (HBC) value of -16.73, indicating that, on average, the Brazilian municipalities will have a deficit of approximately 17 beds. This deficit is projected to occur in 3338 municipalities with the north and northeast regions being at the greatest risk of exceeding health care capacity due to the COVID-19. The intervention scenarios indicate across all of Brazil that they could address the bed shortage, with an average of available beds between 23 and 32. However, when we consider the shortages at a municipal scale, bed exceedances still occur for at least 2119 municipalities in the most effective intervention scenario. Our findings are essential to identify priority areas, to compare populations, and to provide options for government agencies to act. This study can be used to provide support for the creation of effective health public policies for national, regional, and local intervention.