ABSTRACT
OBJECTIVE: Brazil was strongly affected by the COVID-19 pandemic. Its continental dimension and socio-demographic characteristics pose challenges to distribution and accessibility, making vaccination programs challenging. The objectives of the study were to describe the clinical and demographic characteristics of the general population vaccinated against COVID-19 by October 2021 and analyze the strategies implemented during the vaccination program. STUDY DESIGN AND SETTING: A retrospective nationwide study that analyzed data from the OpenDataSUS platform of the Informatics Department of the Brazilian Ministry of Health (DataSUS), which contains information from all individuals in Brazil who have received at least one dose of any vaccine against COVID-19 approved by the National Health Agency (ANVISA) from 17 January to 3 October 2021. RESULTS: Until 3 October, a total of 146,254,578 persons (68.6 per 100 inhabitants) received at least one dose of a vaccine in Brazil. The north and northeast regions had the lowest vaccination rates compared with the remaining regions (North: 56.8, Northeast: 62.0, South: 74.4, and Southeast: 73.2 per 100 inhabitants). Elderly individuals had the highest vaccination rates, particularly those above 70 years old. Heterologous dosing regimens were administered to 1,063,079 individuals (0.7% of those receiving the first dose). CONCLUSIONS: The COVID-19 vaccination program reached more than two-thirds of the population in Brazil by 9 months after its start, but the vaccination coverage was heterogeneous, reflecting the country's geographic and socio-demographic characteristics. Establishing priority groups for vaccination was a main characteristic of the vaccination strategy. In addition, technology transfer agreements have played an important role in increasing vaccine accessibility.
ABSTRACT
OBJECTIVE: Describe a case series of vaccine-induced immune thrombotic thrombocytopenia (VITT) after COVID-19 vaccination in Brazil that included ChAdOx1 nCoV-19, Ad26.COV2.S and BNT162b2 vaccines, describing their clinical and laboratory characteristics. METHODOLOGY: Descriptive case series study using Bio-Manguinhos/Fiocruz/AstraZeneca Brazil and National Immunization Program/Ministry of Health (NIP/MoH) data on COVID-19 AEFI surveillance. We obtained patient-level data from pharmacovigilance for AEFI surveillance and used both the NIP/MoH and Bio-Manguinhos/Fiocruz pharmacovigilance databases to create the study database. Thirty-nine cases of suspect VITT were included, 36 after ChAdOx1 nCoV-19, one after BNT162b2 and two after Ad26.COV2.S vaccine. All cases were based on meeting the Brighton Collaboration criteria for VITT. The primary outcomes were clinical and laboratory features, site of thrombosis, and anti-PF4 ELISA, when available. RESULTS: Thirty-nine cases met the criteria, 38 of which were classified as level 1 and one as level 3 according to Brighton Collaboration. Most cases had the central nervous system (CNS) as the main site of thrombosis (21/39) and happened after the vaccine first dose (34/39). The median age of the cases was 41 years old (23 to 86 yo). Most of the cases (61.5%) occurred in women. The median interval between vaccination and onset of symptoms was 8 days (0-37 days). The platelet count and D-dimer count had median values of 34,000/µL and 19,235 µg FEU/L, respectively. The ELISA anti-PF4 antibody was positive in 18 samples. The overall mortality rate was 51% and was higher in cases of CNS thrombosis with intracerebral bleeding. CONCLUSION: Our case series shows that Brazilian VITT cases have similar clinical and laboratory profiles as demonstrated in the literature. Brazil has administered more than 300 million doses of COVID-19 vaccines (more than 110 million from ChAdOx1 nCoV-19). VITT seems to be a very rare but serious adverse event following COVID-19 immunization, especially adenoviral vector immunization.
