Transmission Dynamics and Parameters for Pertussis during School-Based Outbreak, South Korea, 2024

We estimated the serial interval and superspreading potential to quantify pertussis transmission dynamics in a 2024 school-based outbreak of a population in South Korea that had received a series of pertussis vaccinations. We analyzed 48 cases of pertussis and reconstructed 36 transmission pairs. We then used maximum-likelihood estimation to assess serial interval and offspring distribution from transmission pair data. We identified that the mean serial interval was 9.5 (SD 1.6) days; 15% (95% CI 8%–23%) of cases seeded 80% of all transmissions in this outbreak. Our findings suggest that pertussis was highly transmissible in vaccinated children during this outbreak. Rapid contact tracing and strict adherence to public health measures are needed to reduce community pertussis transmission.