Trends of Bacterial Meningitis Incidence Rate over 20 Years (2000 to 2019): The Israel Experience

Background: Bacterial meningitis (BM) remains a considerable cause of morbidity. Objectives: To evaluate BM incidence rate trends in diverse age groups.Methods: We conducted a retrospective cohort study based on the Israeli national registry. Inclusion criteria were acute admissions 2000 to 2019 with primary diagnosis of BM. Pre-defined age groups were neonates (<= 30 days), infants (31 days to 1 year), younger children (1 <= 5 years), older children (5 <= 18 years), and adults (>= 18 years). Average annual incidence rates per 100,000/year were calculated for the entire period and by decade. Incidence rates for neonates and infants were calculated per 100,000 live births (LB).Results: There were 3039 BM cases over 2 decades, 60% were adults. The overall BM incidence rate was 2.0/100,000/year, neonates, 5.4/100,000/year LB, infants 17.6/100,000/year LB. First year of life incidence rate (neonates and infants com-bined) was 23.0/100,000/year, younger children 1.5/100,000/ year, older children 0.9/100,000/year, and adults 1.8/100,000/ year. All age groups presented a decrease in incidence rate (last decade vs. previous) except neonates, which increased by 34%. Younger and older children presented the most consider-able decrease: 48% and 37% (last decade vs. previous).Conclusions: Adults showed the highest number of BM cases. The incidence rate was highest during the first year of Life (neonates and infants combined). All age groups, except neonates, showed a decreasing trend. Younger and older children present -ed the most considerable decrease, most likely attributable to vaccination. The observed increase in BM incidence rate in neo-nates may influence whether preventive strategy is considered.