Key Points

• Tuberculosis: stable epidemiological situation, with levels remaining steady in Loire-Atlantique at an average of 8.2 reported cases per 100,000 inhabitants per year, higher than the rates in mainland France and the European Union

• Legionellosis: another marked increase in case numbers, up 16% (in Mayenne and Sarthe)

• Invasive meningococcal disease: decrease in case incidence linked to reduced circulation of serogroup C meningococcus following the strengthening of infant vaccination strategies implemented in 2017–2018

• Diphtheria: Cases of diphtheria have occurred since 2020 in the eastern part of the region among men, predominantly those aged 16–21

• Impact of the onset of COVID-19 on the occurrence of most diseases that saw a decrease in incidence in 2020