The epidemiology of measles in Poland: prevalence of measles virus antibodies in the population

WHO has adopted a goal of eliminating indigenous measles from the European Region by the year 2007. The strategy focuses on reducing the proportion of susceptible individuals in the population to low levels and maintaining these low levels of susceptibility. Routine vaccination against measles for children aged 13–15 months was introduced in Poland in 1975, and a second dose added in 1991. High coverage (> 95%) is achieved with both doses. In order to assess progress towards measles elimination in Poland, a serological survey was performed to evaluate the impact of vaccination on the susceptibility profile of population. Three thousand residual serum samples from individuals aged 1–30 years were collected from hospitals in six selected voivodeships (administration units) in Poland. These were tested for measles-specific IgG using a commercial ELISA. Overall 4% (120/3000) were negative for measles virus antibody. The highest proportion of negatives (8·2%) occurred among cohorts born 1977–81 – the only cohorts in which susceptibility exceeded the WHO targets. ‘Catch-up’ vaccination strategies should target these cohorts.

Measles virus antibodies in a laboratory colony of owl monkeys (Aotus trivirgatus)

Serologic testing revealed that 17/84 (20·2%) of bought-in Aotus and 1/31 (3·2%) of colony-born Aotus had haemagglutination-inhibition antibody. Clinically-inapparent measles infections were detected in 3 monkeys by increased antibody titres. Following the detection of a recent infection, antibody titre persisted at a high level for at least 240 days. Although 84% of the monkeys were sero-susceptible, no further serological evidence of measles infection occurred.