Arch Hellen Med, 37(4), July-August 2019, 475-484
Serological immunity against polioviruses among immigrant and refugee children arriving in Greece
C. Ioannidou,1 P. Galanis,2 A. Voulgari-Kokkota,3 E. Bozas,2 A. Mentis,3 K. Tsoumakas,1 I.D. Pavlopoulou1
OBJECTIVE To evaluate the serological immunity against poliomyelitis in newly arrived immigrant and refugee children and associated factors.
METHOD Demographic and immunisation data and specimens of serum were obtained from all immigrant and refugee children aged 1–14 years, attending an outpatient hospital clinic in Athens within three months of their arrival. Immunity against poliomyelitis serotypes 1, 2 and 3 was measured by neutralizing antibody titration in tissue culture microplates according to WHO guidelines; titers ≥8 were considered positive. Analysis was performed with the Statistical Package for Social Sciences (IBM SPSS), v. 21.0.
RESULTS From September 2010 through September 2013, 274 children with a mean age of 7.1 years were recruited, and 20.8% provided vaccination records. The children originated from Asia (198), Eastern Europe (28), the Middle East (24) and Africa (24). The overall prevalence of seropositivity was 84.3%, 86.1% and 74.5% against poliomyelitis serotypes 1, 2 and 3, respectively. Although no difference was observed with respect to the different regions, immigrant children presented statistically significantly higher rates of protection against all three polioviruses than refugee children (polio 1: p=0.002, polio 2: p=0.004, polio 3: p<0.001). Seronegativity against at least one, two, and all three polio serotypes was found in 37 (13.5%), 12 (4.4%), and 30 children (10.9%), respectively, 76.7% originating from Asia. The estimated geometric mean titers were higher for polio 1 (123.9), lower for polio 2 (121.1) and lowest for polio 3 (112.3). Documented receipt of ≥3 vaccine doses was a positive, and increasing age a negative, predictor for seroprotection.
CONCLUSIONS A notable proportion of newly arrived refugee and immigrant children present serological susceptibility to one or more polioviruses. Certain demographic characteristics appear to be risk factors for seronegativity. These findings provide useful information and support for immediate targeted and intervention to protect this vulnerable population.
Key words: Children, Immigrants, Poliovirus, Refugees, Serological immunity.