Timeliness of childhood vaccinations in Armenia, 2015-2016.

Background: Successful control of vaccine preventable diseases not only requires high coverage but also requires that vaccines are administered in a timely manner. Prior studies have examined the timing of vaccinations in Armenia and found that although vaccination coverage is high, children are not receiving the vaccinations in a timely manner. This study aims to further elucidate the timing and associated factors of childhood vaccinations among children in Armenia in 2015-2016.

Methods: Data from the Armenia Demographic and Health Survey (ADHS) from 2015 to 2016 were used to examine the timing of WHO-recommended vaccinations during the first year of life of all living children under three years of age, which included a vaccine against tuberculosis (BCG), three doses of a diphtheria, pertussis and tetanus vaccine (DTP), three doses of a polio vaccine (Pol) and a measles-containing vaccine (MCV). The Kaplan-Meier method was used to assess age-appropriate receipt of vaccinations. Cox proportional hazards models with a shared gamma frailty to account for clustered sampling were used to determine factorsassociatedwith timely vaccinations.

Results: Vaccination coverage was high ranging from 80.6% for the third dose of DTP to 98.4% for BCG, yet the proportion of children with delayed vaccinations increased with each dose in a series, with 51.9% and 48.5% having a delayed receipt of the third doses of DTP and Pol respectively. Factors associated with delayed vaccinations included female gender, certain regions of residence, previously delayed vaccinations, poorer wealth index and lower educational level of mother. There were no differences in timing of vaccinations between clusters.

Conclusions: Although coverage was generally high, a high proportion of children under three in Armenia experienced delays in receiving the recommended vaccinations. Continued focus on adherence to the immunization schedule is necessary to ensure optimal coverage and protection for children in Armenia from vaccine preventable diseases.