Trend in mandatory immunisation coverage: linear and joinpoint regression approach, Serbia, 2000 to 2017

Abstract

Background Analyses of temporal trends in immunisation coverage may help to identify problems in immunisation activities at specific points in time. These data are essential for further planning, meeting recommended indicators, monitoring, management and advocacy. Aim This study examined the trends of mandatory vaccination coverage in the period 2000–2017 in Serbia. Methods Data on completed immunisations were retrieved from annual national reports of the Institute of Public Health of Serbia during the period 2000–2017. To assess the trends of immunisation coverage, both linear and joinpoint regression analyses were performed. A probability p < 0.05 was considered significant. Results Over the period 2000–2017 linear regression analysis showed a significant decline in coverage with the primary vaccination against poliomyelitis, diphtheria, tetanus, pertussis and measles, mumps, rubella (MMR) (p ≤ 0.01). In the same period, coverage of all subsequent revaccinations significantly decreased, namely, first revaccination for pertussis (p < 0.01); first, second and third revaccination against diphtheria, tetanus and poliomyelitis (p < 0.01); and second dose against MMR before enrolment in elementary school (p < 0.05). Although linear regression analysis did not show change in vaccination coverage trend against tuberculosis (Bacillus Calmette–Guérin; BCG), hepatitis B (HepB3) in infants and diseases caused by Haemophilus influenzae type b (Hib3), the joinpoint regression analysis showed that the coverage declined for BCG after 2006, HepB3 after 2010 and Hib3 after 2008. Conclusion To achieve and keep optimum immunisation coverage, it is necessary to address barriers to immunisation, such as the availability of all vaccines and vaccine-hesitancy among parents and healthcare workers in Serbia.