Peer-reviewed article
Varicella outbreak at the Itamaraju Indigenous Health Base Center: a descriptive study, Bahia, 2024.
Guilherme Alves de Siqueira, Leticia Stanczyk, Benvindo Joãozinho Sá, Lucimeire Neris Sevilha da Silva Campos, Vanessa Cristina Fragoso Farias et al. ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001A varicella (chickenpox) outbreak occurred in indigenous villages in Bahia, Brazil in 2024, affecting 42 people including 19 children aged 7-13 years. The outbreak was traced to schools where indigenous and non-indigenous students mixed, with attack rates of 6.2% in one school and 7.0% in another. Vaccination coverage in the affected community was below national targets, with 90% receiving the first dose but only 70.3% receiving the second dose. The outbreak was brought under control after 101 days through vaccine updating and active case searching.
Key points
- 42 varicella cases identified, with 19 children aged 7-13 years and equal distribution between sexes
- 14 cases had received no varicella vaccine; 16 children were vaccinated after the outbreak began
- Attack rate was 6.2% (25/403) in one school and 7.0% (3/43) in another school
- Varicella vaccination coverage was 90.0% for first dose but only 70.3% for second dose, below national targets
- Outbreak controlled 101 days after the first case through vaccine updating and active case search
Limitations
This is a descriptive outbreak investigation without comparison groups or evaluation of specific interventions, so it cannot determine which control measures were most effective or compare outcomes between vaccinated and unvaccinated children. The study does not provide detailed information about disease severity, complications, or long-term impacts on the affected children.
Abstract
OBJECTIVE: To investigate varicella cases in the Itamaraju indigenous territory base center and calculate the varicella vaccination coverage in the Tawá village, Bahia, 2024. METHODS: Descriptive study of case series and census vaccination survey in children from the Tawá village conducted between June 6 and July 3, 2024, on the secondary survey database released by the General Coordination for Immunopreventable Diseases. We used descriptive statistics with measures of absolute and relative frequency and central tendency and dispersion. RESULTS: We identified 42 cases, equally distributed between the sexes, with 27 indigenous persons and 19 children aged 7-13 years, and 14 cases received no varicella vaccine. There were 23 cases in the Tawá, Mucujê, Canto da Mata and Corumbauzinho villages, and 25 cases were associated to a school in the Tawá village, with indigenous and non-indigenous students, with an attack rate of 6.2% (25/403). In another indigenous school (Mucujê village), the attack rate was 7.0% (3/43). For the cases with available information (n=31), the most frequent symptoms were exanthema (31/31), pruritus (24/31) and fever (21/31). The varicella vaccination coverage was 90.0% (54/60) for the 1st dose and 70.3% (26/37) for the 2nd dose. Sixteen children received varicella vaccine after the outbreak began: seven received the first dose and nine received the second dose. Immunoglobulin was used for one pregnant woman. The outbreak was controlled 101 days after the first case. CONCLUSION: The occurrence of the outbreak in the indigenous territory was confirmed. The varicella vaccination status in the Tawá village was below the target recommended by the National Immunization Program. Vaccine updating and active case search were implemented.