Poor immunity status against poliomyelitis in medical students: a semi-anonymous study

In spite of almost complete eradication, poliomyelitis continues to be a global threat even in non-endemic countries due to the ever-increasing international travel activities. Health care workers are at a special risk in acquiring pathogens from travelers returning from endemic countries. Polio vaccines are fairly well accepted throughout the German population. Yet, laboratory controls for successful immunization are carried out only sporadically in the general population, and not even the medical staff are routinely tested for polio immunity. The present study was initiated in order to assess the immunity status of young people at the very beginning of their career in clinical medicine. Within their first clinical semester, all students are supposed to undergo an obligatory health check in our Occupational Medicine Unit. A blood sample is taken and sent under a personal code to our diagnostic laboratories for virus serology, and for cryoconservation of residual serum, if available. Within the periods 2004-2006 and 2008-2010, we analyzed sera from 424 and 427 individuals, respectively, for anti-polio types 1, 2, 3 antibodies by a microneutralization assay. In the latest study period, there was a slight increase in the rate of fully protected persons: 63.9 % triple-seropositivity versus 57.1 % in the period 2004-2006. By the end of the second clinical semester, students with low or negative antibody levels (1:<10) were informed, and a (booster) vaccination was recommended.