Seroepidemiology of Polioviruses among University Students in Northern Italy

Abstract

The widespread use of poliovirus vaccination schemes has led to a marked decline in the incidence of paralytic poliomyelitis worldwide, but wild poliovirus is still endemic in some developing countries, and in 2009 a total of 23 countries reported at least 1 case of poliomyelitis caused by wild-strain polio viruses. A serological survey was thus conducted on the immunological status against polioviruses of 318 young adults, classified by their country of origin. Immunity to poliomyelitis was assessed by neutralizing antibody titration in tissues cultured on microplates. The rate of seronegativity (<1:8) in the study population was 26.7% for poliovirus type 1, 7.2% for type 2, and 22.6% for type 3. In our sample of 318 individuals, 219 (68.9%) were Italian and 99 (31.1%) were from outside the European Union (EU). The proportion of cases found seropositive to polioviruses 1 and 3 decreased significantly with older age; this age-related decrease was more evident in the Italian group than among the non-EU subjects. Any risk of the wild virus recurring and causing paralytic poliomyelitis must be prevented, keeping Europe polio free by means of appropriate immunological protection, until polio has been conclusively eradicated all over the world. Judging from our findings, it may be worth considering administering a fifth dose of polio vaccine to adolescents.

Assessment of seroprevalence against poliovirus among Italian adolescents and adults

“…Similarly, a reduction in neutralising antibodies levels according to age was found in university students whether Italian or from outside EU. 7 Seropositivity rates very close to 100% were observed in Apulian children from zero to 15 years old, with the lowest titres in infants in the first year of life who have not concluded immunisation and a decline of GMT associated with age, particularly for PV3 again. 5 As the risk of reintroduction of the virus is strongly reduced but still not completely eliminated, the low and decreasing levels of immunity in adolescents represent a matter of concern.…”

“…Two cases of imported wild viruses were detected in not vaccinated children coming from Iran (1984) and India (1988). 6,7 A sequential schedule composed of two doses of IPV (at 3 and 5 months) and two of OPV (at 11 months and 3 years of age) was employed since 1999. Since July 2002, a four doses IPV schedule was adopted.…”

Investigation et riposte à une épidémie de poliovirus sauvage à Kinshasa

“…Une enquête sérologique menée en Italie a montré que la proportion des sujets séropositifs au PVS de type décroit avec l’âge. Une étude basée sur une évaluation sérologique du niveau d'immunité des sujets aurait été plus fiable [9, 10]. …”

Business travelers: vaccination considerations for this population

“…When German medical students in Bonn were tested by microneutralization assay for antipolio antibodies types 1, 2, 3 during 2004-2006 and 2008-2010, triple-seropositivity was present in only 57 and 64%, respectively [33]. Another study found seronegativity (defined as antibody titers ≤1:8) in university students in northern Italy in significant proportions: 26.7% for poliovirus type 1, 2.8% for type 2 and 22.6% for type 3 [34]. Seropositivity declined with older age, especially in the Italian group [34].…”

“…Another study found seronegativity (defined as antibody titers ≤1:8) in university students in northern Italy in significant proportions: 26.7% for poliovirus type 1, 2.8% for type 2 and 22.6% for type 3 [34]. Seropositivity declined with older age, especially in the Italian group [34]. Business travelers, particularly those who anticipate travel to many emerging market economies, should be assessed for their polio vaccine status.…”