Key Points

• In Mayotte in 2024, there has been a sharp increase in the number of PCR-confirmed pertussis cases compared to previous years, with 125 cases reported as of September 18, 2024, compared to 17 cases in 2023 and 8 cases in 2022.

• This resurgence is part of a national and European trend in 2024 toward a high-intensity resurgence of pertussis.

• The increase in the number of pertussis cases in Mayotte has been observed primarily since the beginning of June 2024 (23 cases), with 55 cases recorded in August alone. In week 37, 1 case was reported, seemingly confirming the decrease in the number of cases observed in weeks 35 (n=7) and 36 (n=7).

• In mainland France, the public health situation differs in terms of timing; public health indicators (emergency room visits, SOS Médecins, sentinel physician network) showed a sharp increase in intensity between Week 10 and Week 26.

• In Mayotte, the outbreak primarily affects children under 1 year of age (69 cases, 55%), followed by children aged 1 to 3 years (22 cases, 18%); 20 (16%) cases were reported among adults aged 18 and older (maximum age: 66 years).

• Two deaths were reported among unvaccinated infants and their mothers; no new deaths were reported in weeks 36 and 37.

• Cases are concentrated mainly in the north and east of the department, with an incidence rate of 72.8 cases per 100,000 inhabitants in Mamoudzou, 37.9 per 100,000 inhabitants in Dembeni, and 37.3 per 100,000 inhabitants in Koungou.

• The Department of Health Security and Emergencies (Désus) of the Mayotte Regional Health Agency (ARS) conducted 20 home visits, resulting in 118 catch-up vaccinations and the prescription of 84 courses of antibiotic prophylaxis.

• In terms of vaccination, the 2019 survey of vaccination coverage in the general population estimated a fairly good vaccination coverage rate of 92.2% among children aged 24–59 months against pertussis, though this was below the herd immunity threshold set at 95%.