Invasive Pneumococcal Disease in Latvia in PCV10 Vaccination Era, 2012-2018.

In 2010 in Latvia, invasive pneumococcal disease (IPD) became a cause for concern and vaccination of infants with four doses of 7-valent pneumococcal conjugate vaccine (PCV7) commenced. In 2012, 10-valent pneumococcal conjugate vaccine (PCV10) (three doses at 2, 4, and 12-15 month of age) vaccination was introduced. We described incidence and serotype distribution of IPD in Latvia and investigated serotypes associated with death from IPD based on surveillance data. Adult vaccination against pneumococcal infection is not included in the national immunization program. Laboratory confirmed IPD cases are passively notified to the Center for Disease Prevention and Control of Latvia (CDPC) by laboratories and clinicians. We calculated incidence by age, sex, case fatality, and trend in serotypes by conducting a retrospective population-based cross-sectional study based on national IPD surveillance data. From 2012 to 2018 466 cases of IPD were reported. The highest notified incidence was in 2015 at 4.4/100,000, which fell to 3.9 in 2018. The highest mean annual IPD incidence was in infants (4.8) and in the elderly (6.0). PCV10 vaccine serotypes were the most prevalent in IPD cases up to 2015 with a decreasing trend from 50% (20/40) in 2012 to 19% (14/74) in 2018 (chi2 test for trend of odds = 0.000). PCV23nonPCV13 vaccine serotypes had an increasing trend and rose from 18% (7/40) to 34% (25/74) (chi2 test for trend of odds = 0.000). Non-Vaccine serotypes had an increasing trend and rose from 13% (5/40) to 27% (20/74) (chi2 test for trend of odds = 0.038). Reported total case fatality was 19% (87/466). The highest, at 36% (20/56), was reported in 2013. After adjusting for age, Streptococcus pneumoniae serotype 3 was associated with death from IPD (adjusted OR 2.3 95%CI 1.25-4.12 p 0.007). Surveillance data indicate evidence of serotype replacement with an increasing trend of serotype 19A and PPV23nonPCV13 and Non-Vaccine serotypes. Serotype 3 and age were associated with fatal IPD outcome. Further studies of S. pneumoniae carriage would be useful in providing more evidence to characterize serotypes' circulation.

Serotype Distribution of Remaining Pneumococcal Meningitis in the Mature PCV10/13 Period: Findings from the PSERENADE Project.

Pneumococcal conjugate vaccine (PCV) introduction has reduced pneumococcal meningitis incidence. The Pneumococcal Serotype Replacement and Distribution Estimation (PSERENADE) project described the serotype distribution of remaining pneumococcal meningitis in countries using PCV10/13 for least 5-7 years with primary series uptake above 70%. The distribution was estimated using a multinomial Dirichlet regression model, stratified by PCV product and age. In PCV10-using sites (N = 8; cases = 1141), PCV10 types caused 5% of cases <5 years of age and 15% among ≥5 years; the top serotypes were 19A, 6C, and 3, together causing 42% of cases <5 years and 37% ≥5 years. In PCV13-using sites (N = 32; cases = 4503), PCV13 types caused 14% in <5 and 26% in ≥5 years; 4% and 13%, respectively, were serotype 3. Among the top serotypes are five (15BC, 8, 12F, 10A, and 22F) included in higher-valency PCVs under evaluation. Other top serotypes (24F, 23B, and 23A) are not in any known investigational product. In countries with mature vaccination programs, the proportion of pneumococcal meningitis caused by vaccine-in-use serotypes is lower (≤26% across all ages) than pre-PCV (≥70% in children). Higher-valency PCVs under evaluation target over half of remaining pneumococcal meningitis cases, but questions remain regarding generalizability to the African meningitis belt where additional data are needed.

Prevention and control of meningococcal disease: Updates from the Global Meningococcal Initiative in Eastern Europe.

The Global Meningococcal Initiative (GMI) aims to prevent invasive meningococcal disease (IMD) worldwide through education, research and cooperation. In March 2019, a GMI meeting was held with a multidisciplinary group of experts and representatives from countries within Eastern Europe. Across the countries represented, IMD surveillance is largely in place, with incidence declining in recent decades and now generally at <1 case per 100,000 persons per year. Predominating serogroups are B and C, followed by A, and cases attributable to serogroups W, X and Y are emerging. Available vaccines differ between countries, are generally not included in immunization programs and provided to high-risk groups only. Available vaccines include both conjugate and polysaccharide vaccines; however, current data and GMI recommendations advocate the use of conjugate vaccines, where possible, due to the ability to interrupt the acquisition of carriage. Ongoing carriage studies are expected to inform vaccine effectiveness and immunization schedules. Additionally, IMD prevention and control should be guided by monitoring outbreak progression and the emergence and international spread of strains and antibiotic resistance through use of genomic analyses and implementation of World Health Organization initiatives. Protection of high-risk groups (such as those with complement deficiencies, laboratory workers, migrants and refugees) is recommended.