Emergence of pneumococcal meningitis outbreak in Northern Togo in 2023, lessons learned and challenges

Outbreaks of Streptococcus pneumoniae (Spn) meningitis are uncommon, typically more severe with high mortality. In Epi-week 4, 2023, Oti-Sud district in Togo reached for the first time, the epidemic threshold with 13 Spn cases despite the introduction of PCV13 into the routine EPI in 2014. The outbreak was investigated to describe its magnitude and document lessons learned to inform preparedness and response for future outbreaks. This cross-sectional study analyzed Spn meningitis outbreak data from Oti-Sud district (Savanes region), Epi-week 49, 2022 to Epi-week 23, 2023 to describe the attack and case fatality rates (AR & CFR), patients’ sociodemographic and clinical characteristics across the district and its three surveillance zones (Z1, Z2 and Z3). Additionally, we analyzed routine surveillance data from Savanes region, Epi-week 1, 2016 to Epi-week 17, 2019 to compare Spn and Neisseria meningitis (Nm) case characteristics and scrutinized the Spn outbreak’s After Review Action report to document lessons learned. Meningitis’ case definitions and epidemic thresholds followed WHO guidelines. We performed descriptive analysis and summarized findings using median, ratio and proportions. Epidemic threshold was reached with a weekly AR of 10 cases per 100,000 population. A total of 153 cases was notified from Epi-week 49, 2022 to Epi-week 23, 2023 representing a cumulative AR of 117.4 and was 192.6 in Z1; Z2: 55.4 and Z3: 74.7. The cumulative CFR was 7.8%(12/153), ranged from 8.1%(6/74) in females and 7.6%(6/79) in males, p-value = 0.9132 with a significant difference within zones (Z1: 5.8%(6/104), Z2: 17.4%(4/23) and Z3: 7.7%(2/26), p-value < 0.0001). Female to male sex ratio was 0.48(74/153), median age: 15 years, IQR: [11–24] and all cases were from rural area. Spn outbreak showed parallels to Nm’s. Zone-based surveillance, continuous capacity building, systematic daily data analysis and monitoring, community engagement contributed to outbreak detection and community compliance to response measures. Key bottlenecks included limited laboratory testing capacity, absence of strain sequencing, incomplete routine vaccination records, and lack of sequelae data. Spn meningitis outbreak emergence in northern Togo magnitude was high with similarities with Nm’s. Defeating meningitis by 2030 requires laboratory capacity reinforcement, comprehensive and accurate surveillance data including routine vaccination and sequalae data.