COVID-19 cluster in vaccinated healthcare workers in Mayotte.

We report a significant cluster of SARS-CoV-2 (B.1.617.2 variant) among young healthcare workers (HCW) (median age of 27years) living in the Mamoudzou interns apartment complex, belonging to the Hospital Center in Mayotte. Among them, 18 developed SARS-CoV-2 infection (62.1%) and all were symptomatic. The infection rate was higher for people who had had a second dose more than 6 months before than for those who had had a second dose less than 6 months before (P=0.05). This epidemic had no individual consequence, but the hospital functioning in Mayotte was significant impacted. This report reinforces the need for a third dose of vaccine among HCWs, in addition to non-pharmaceutical measures.