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

Larisa Savrasova; Angelika Krumina; Hedija Cupeca; Indra Zeltina; Anita Villerusha; Ilze Grope; Ludmila Viksna; Elina Dimina; Sooria Balasegaram

doi:10.3389/fped.2021.532489

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

Front Pediatr. 2021 Oct 7:9:532489. doi: 10.3389/fped.2021.532489. eCollection 2021.

Authors

Larisa Savrasova¹, Angelika Krumina², Hedija Cupeca³, Indra Zeltina², Anita Villerusha⁴, Ilze Grope³, Ludmila Viksna², Elina Dimina⁵, Sooria Balasegaram⁶

Affiliations

¹ Centre for Disease Prevention and Control of Latvia, The European Programme for Intervention Epidemiology Training (EPIET), Riga Stradinš University, Riga, Latvia.
² Department of Infectology, Riga Stradinš University, Riga, Latvia.
³ Department of Pediatrics, Riga Stradinš University, Riga, Latvia.
⁴ Department of Public Health and Epidemiology, Riga Stradinš University, Riga, Latvia.
⁵ Centre for Disease Prevention and Control of Latvia, Riga, Latvia.
⁶ The European Programme for Intervention Epidemiology Training (EPIET) Coordinator, Public Health England Field Epidemiology Service South East and London, London, United Kingdom.

Abstract

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.

Keywords: Latvia; PCV10; S. pneumoniae serotype replacement; invasive pneumococcal disease; pneumococcal conjugate vaccine (PCV).