Estimation of 13-valent pneumococcal conjugate vaccine efficiency in infants within national immunization schedule

Abstract

Background. Vaccination of infants with 13-valent pneumococcal conjugate vaccine (PCV) was implemented in national immunization schedule in 2014. In this regard epidemiological monitoring of routine immunization results with vaccination coverage and efficiency control is required. Objective. Our aim was to study correlation between pneumococcal disease routine immunization in infants and morbidity and mortality rates due to community-acquired pneumonia in children under 18 years of age and morbidity rate due to acute otitis media in children under 14 years of age. Methods. Morbidity (Form No. 2, 2011-2017 yrs) and mortality (Form No. 51S, 2009-2017 yrs) rates due to community-acquired pneumonia, morbidity rate (Form No. 12, 2009-2017 yrs) due to acute otitis media, vaccination coverage rate (Form No. 5, 2014-2017 yrs, and Form No. 6, 2016-2017 yrs) were analysed according to the data of Forms of Federal Statistical Monitoring. Medical exemptions and refusals to vaccinate rates were estimated according to the data from doctors who was performing infants vaccination. Results. During PCV routine vaccination within national immunization schedule in Russian Federation the 35% reduction of mortality due to community-acquired pneumonia in children under 1 year of age as well as reduction of morbidity with acute otitis media have been established. Moreover, low percentage of etiology clear community-acquired pneumonias (29%) complicates the estimation of vaccination efficiency. It has been revealed that despite the high pneumococcal disease vaccination coverage rate of infants under 2 years of age (87%), considerable part of children (73%) are vaccinated untimely in most Russian Federation regions. 9.3% (3.4% due to medical exemptions) of children (among 1st year infants) remained unvaccinated due to medical exemptions and refusals to vaccinate in 2016, and 8% (3.4%) in 2017 respectively. Conclusion. Implementation of PCV routine immunisation for three years in a row leads to reduction of morbidity rate due to acute otitis media among children under 14 years of age and infant mortality rate due to community-acquired pneumonias. Though, the estimation of routine immunisation efficiency can be difficult due to such factors as untimely start of vaccination, medical exemptions and refusals to vaccinate and limited laboratory diagnostics of community-acquired pneumonias etiology.