Key Points

Five months after the first confirmed case of COVID-19 in Mayotte, the outbreak continues in the department. Since the disease was first detected in the territory, 3,031 people have tested positive for COVID-19 out of a total of 14,079 tested.

The incidence of the disease was very high in week 19, when a peak of 387 new cases was reported, representing a rate of 139 cases per 100,000 inhabitants. This rate has since declined steadily through week 28, reaching 21 cases per 100,000 inhabitants, before rising again in week 29 and stabilizing at 34 cases per 100,000 inhabitants over the past two weeks. This new rise in incidence could be partly explained by the active testing campaigns implemented across the region in recent weeks.

The positivity rate for SARS-CoV-2 tests decreased slightly from 11% in week 30 to 8% in week 31, falling below the 10% alert threshold. This decline in the positivity rate should be interpreted with caution, as these data need to be consolidated over the coming weeks. As of August 4, 2020, a total of 19 clusters have been identified in Mayotte (excluding small family clusters) since the start of the epidemic. To date, 16 have been resolved, but 3 remain active. The last two clusters were reported in early August. The reporting of these two new clusters in week 31—one of which occurred among an informed population during a public event—highlights the relaxation of preventive measures and the fragility of the epidemiological situation, hence the need to maintain the department at a high vulnerability level.

Testing campaigns are being implemented around each cluster as well as in the context of the resumption of economic activities. For example, a large-scale testing campaign was conducted in a town in the north of the island during weeks 30 and 31, where a cluster had been identified. This campaign tested 324 people, 47 of whom tested positive for COVID-19. Similarly, since late July, travelers wishing to visit Réunion have been systematically tested, and samples are analyzed at the Réunion University Hospital laboratory. These testing campaigns make it possible to detect asymptomatic cases with no confirmed contact with a confirmed case.

The continued circulation of the virus in the department and the persistence of relatively high epidemiological indicators strongly call for maintaining the highest level of vigilance and responsiveness. To this end, a new testing strategy has been implemented since week 31. All close contacts of identified cases are encouraged to get tested. For family members of the case or people living in the same household, testing must be done immediately, while for non-family contacts, testing must be done within 5 to 7 days of the date of the last contact. This new measure, which implements national recommendations, should help break the chains of transmission around identified cases.