Measles outbreak investigation, Greater Francistown District, Botswana, 2023

Introduction: Measles causes significant childhood morbidity and mortality worldwide. Botswana has targeted measles for elimination. On January 7 2023, the Greater Francistown district health management team was informed of a suspected measles outbreak. We investigated the outbreak to verify the diagnosis, describe the epidemiological characteristics of cases and institute control measures. Methods: We adapted the World Health Organization case definition for measles. We conducted active case search, interviewed caregivers, patients, community members and reviewed medical records. We collected patient’s demographic, clinical, and exposure history. Blood samples obtained from community cases were sent to the National Health Laboratory, Gaborone. We summarized data using summary statistics, frequencies and proportions. Results: From week 52, 2022 to week 36, 2023, we identified 25 cases (CFR: 0%): 21 confirmed and 4 probable cases. All 25 (100%) cases presented with a maculopapular rash and fever; one (4%) case was hospitalized. Median age was 7 years (range: 1 – 24 years). Persons aged <10 years accounted for 72% (18/25) cases, 64% (16/25) were males, 72% (18/25) Bazezurus and 52% (13/25) lived in Chadibe. Eight percent (2/25) reported travel to a country with a confirmed measles outbreak. Sixty-four percent (16/25) had not received Measles Containing Vaccine (MCV) dose, 89% (16/18) of these were Bazezurus. The measles vaccination coverage was 98% in Chadibe, and MCV1 coverage amongst Bazezurus was 42%. Conclusion: The measles outbreak in Greater Francistown may have resulted from vaccine refusal by a vaccine-hesitant religious group leading to pockets of measles susceptible children.