Low percentages of measles vaccination coverage with two doses of vaccine and low herd immunity levels explain measles incidence and persistence of measles in the European Union in 2017–2018

Several factors may explain why measles persisted in the European Union in 2017–2018. The study assessed mean measles vaccination coverage and anti-measles herd immunity levels in the target measles vaccination population in countries of the European Union during the 2015–2017 period. The study found that the measles vaccination coverage with two doses of vaccine was < 95% in 28 (96.5%) countries, and that the prevalence of individuals with vaccine-induced measles protection in the target vaccination population was lower than the herd immunity threshold of 94.4% in 22 (75.9%) countries during 2015–2017. The study found a significant negative correlation between the incidence of measles in 2017–2018 in different countries of the European Union and measles vaccination coverage with two doses of measles vaccine, prevalence of individuals with vaccine-induced measles protection and herd immunity levels in the target measles vaccination population during 2015–2017. Measles vaccination coverage and herd immunity levels did not improve from 2010–2015 to 2015–2017 in the European Union. Low percentages of measles vaccination coverage with two doses of vaccine and low herd immunity levels could explain measles incidence in countries of the European Union in 2017–2018. New measles prevention strategies should be developed to increase measles vaccination coverage and herd immunity levels in the European Union.