Why does measles persist in Europe?

Several reasons may explain why measles was not eliminated by 2015 and continues to persist in Europe, including low measles vaccination coverage, low anti-measles herd immunity levels, and the mobility of individuals with measles across Europe. The study assessed the mean measles vaccination coverage in the European Union and the WHO European region with one and two doses of measles vaccine from 1980 to 2015, and the prevalence of vaccine-induced protected individuals and anti-measles herd immunity levels in the WHO European region during 2000–2015. The study found that measles vaccination coverage with two doses of vaccine was <90% in the European Union and the WHO European region from 1995 to 2015. In the WHO European region, the two-dose measles vaccination coverage during the 2000–2015 period was <95% in 41 countries (79%), and the prevalence of vaccine-induced protected individuals in the target vaccination population was lower than the herd immunity threshold of 94.4% in 33 countries (63%). The additional vaccination coverage required to establish herd immunity in these countries ranged from 0.2% to 18%. Two of the factors explaining measles persistence in Europe in 2015 were the two-dose measles vaccination coverage <95% and the prevalence of individuals with vaccine-induced protection of <94.4% in most countries of the WHO European region during the 2000–2015 period. Screening and vaccination programs should be developed to detect and immunize susceptible individuals in areas and population groups without anti-measles herd immunity in all European countries.