Poliomyelitis risks in adolescents and adults in global pre-eradication era

Abstract

INTRODUCTION: In 2012 only 218 cases of paralysis by wild polioviruses were reported around the world, but the risk of contracting polio by wild polioviruses or by vaccine-derived polioviruses (VDPV) has not been wholly eliminated. Currently, most children is protected by polio vaccination, but there are concerns about adolescents and adults who lose the protective antibodies.
OBJECTIVE: To critically analyze the articles that deal with the risks of polio, and vaccination strategies for adolescents and adults.
METHODS: The articles were identified through PubMed and SciELO databases searches in the period from January 2000 to December 2012. World Health Organization, US Centers for Disease Control and Prevention, European Centre for Disease Prevention and Control, Pan American Health Organization, and the Brazilian Ministry of Health websites were also consulted to check the most recent information about epidemiology and diagrams of vaccination.
RESULTS: Polio is more severe in adolescents and adults than in children. The proportion of potentially unprotected people increases with age and a large number of individuals aged over 15 do not have neutralizing antibodies against poliovirus, mainly PV3. Children who have received oral poliovirus vaccine eliminate the vaccine viruses by approximately two to three months and those are immunocompromised can eliminate the virus for years. The Sabin strains are genetically unstable and exposure to VDPV may represent risk for non-immune people of any age.
CONCLUSION: It is necessary to review the recommendations to vaccinate adolescents and adults, mainly healthcare professionals and travelers. Environmental surveillance must be stimulated to detect the risks of the emergence of mutant strains and possible importation of poliovirus by immigrants. The carrying out of seroepidemiologic studies can help to decide on the best vaccination strategies for such groups.