Suboptimal Serologic Immunity Against Poliomyelitis Among New Migrant Children in Greece Calls for Organized Action

Migration-flows pose the risk of poliovirus reintroduction from endemic countries to Greece. This study aims to evaluate serologic-immunity/vaccination against poliomyelitis in newly-arriving migrant children.

Demographic-immunisation data and blood-serum were obtained from migrants 1-14years-old, referred to a hospital-clinic in Athens-Greece within three months from arrival. Immunity to polioviruses-1-3 was determined by serum-neutralizing-antibodies(WHO guidelines). Titers ≥ 1:8 were considered positive.

From 9/2010 to 9/2013, 274 children(150 refugees/124 immigrants), mean age 7.1years-old, were enrolled. Only 57(20.8%) of them presented with vaccination-records. Children originated mainly from Asia(n = 198), Eastern Europe(n = 28), Middle East(n = 24) and Africa(n = 24) with 160(58.4%) from polio-endemic-countries(Afghanistan-112(40.8%), Pakistan-24(8.8%) and India-24(8.8%)). Seropositivity against polio-1-2&3 was 84.3%, 86.1% and 74.5%, respectively. Immigrants, had higher seroprotective rates against polioviruses-1-2&3 than refugees(polio-1:p = 0.002;polio-2:p = 0.004,polio-3:p < 0.001). Seronegativity to 1PVs-2PVs and all three polio serotypes was found in 37(13.5%),12 (4.4%), and 30 children(10.9%) respectively. Increasing number of vaccine-doses, and younger-age, were positively-associated with seropositivity.

A remarkable fraction of newly-arrived migrant-children were seronegative to one or more polioviruses.