Title : Predicted coverage by 4CMenB and MenB-Fhbp vaccine against invasive serogroup B neisseria meningitidis isolated from 2017-2019 in Lithuania
The incidence of invasive meningococcal disease (IMD) in Lithuania was among the highest in Europe during the past two decades reaching an average of 2.24 cases/100,000 population. The vast majority of IMD cases were caused by serogroup B meningococci. In 2018, the only four-component meningococcal B vaccine (4CMenB) was introduced to Lithuania’s National Immunization program. The twocomponent meningococcal B vaccine (MenB-Fhbp) is registered for the vaccination of individuals 10 years and older, but the cost of the vaccine is not reimbursed. Studies on the potential coverage of MenB vaccines in Lithuania would contribute to better monitoring of vaccination impact and planning of future prophylactic strategies. We genotyped 60 serogroup B isolates collected in Lithuania between 2017-2019. The clonal complexes most frequently identified were cc32 (78.3%) and cc41/44. Vaccine relate antigens were obtained, as follows: targeted gene amplification and sequencing were provided for 37 isolates recovered in 2017, whereas whole genome sequencing was performed for 23 isolates recovered in 2018-2019. Meningococcal strain coverage by 4CMenB and MenB-Fhbp vaccine was predicted using the genetic Meningococcal Antigen Typing System (gMATS) and Meningococcal Deduced Vaccine Antigen Reactivity (MenDeVAR) Index methods, respectively. Vaccine coverage using gMATS was estimated for 58 MenB isolates (2017-2019), as PCR of vaccine antigens was not obtained for two isolates. gMATS predicted 53 (91.4%, CI 81.4-96.3%) covered isolates, 1 (1.7%) non-covered isolate, and 4 (6.9%) unpredictable isolates. Most serogroup B isolates (87.9%) were covered by a single vaccine antigen, most commonly Fhbp peptide variant 1 (84.5% of isolate), which is linked with cc32. The overall level of strain coverage by the 4MenB vaccine was 94.8% (CI 85.9-98.2%). The Fhbp peptides included in the MenB-Fhbp vaccine were not detected among the analyzed invasive isolates; however, the identified predominant variant 1 was considered crossreactive. In total, 88.1% (CI 77.5-94.1) of isolates were predicted to be covered by the MenB-Fhbp vaccine. In conclusion, both serogroup B vaccines demonstrate the potential to protect against IMD in Lithuania.
Audience take away:
? Genetic tools to estimate meningococcal B vaccine coverage successfully replace sophisticated assays which require trained personnel and cultivable meningococcal strains.
? Molecular data on vaccine coverage is currently sparse for Eastern European countries.
? Estimation of potential coverage of meningococcal B vaccine is relevant to determine the Sample Abstract Template right target age group for vaccination.
? Other faculty could use the results of this study to expand their research or teaching to address public health interventions.