Epidemiology of invasive meningococcal disease in Greece, 2006-2016.

The present study describes the epidemiology of invasive meningococcal disease (IMD) in Greece for the period 2006-2016. Combined data from notified and laboratory-confirmed IMD cases were obtained from the two involved National Centres (Epidemiology and Reference Laboratory). Laboratory identification and typing was carried out by both conventional (culture) and molecular methods (PCR, MLST, PorA, and FetA typing). A total of 796 IMD cases were notified; of those, 720 (91%) were laboratory confirmed. Overall, a decline on the annual incidence of confirmed cases was observed, ranging from 0.91 (2006) to 0.47 (2016) /100,000. A similar trend was observed in most age groups especially in children 0-4 years (7.7 to 2.9/100,000), with the exception of an increase in the incidence rate in adults > 20 years (0.21 to 0.32/100,000). The overall case fatality rate was 6.5% (52/796), annual range 2-13%. Among 658 strains which were typed by sero/genogroup, 80% were identified as MenB (annual range 65-92%); however, a decline was observed in MenB incidence from 5.3 (2006) to 2.7 (2016), among infants and toddlers, while MenW (1%), MenY (2%), and MenA (1%) remained low. During the 11 years, the annual incidence of IMD declined by 50%, especially in the 0-4-year age group, due mainly to MenB. Continuous surveillance of IMD is important for the development of future vaccination and public health policies.