Is Italian population protected from Poliovirus? Results of a seroprevalence survey in Florence, Italy

Abstract

Objectives: Periodical assessments of population susceptibility to polioviruses (PV) is essential for evaluating population protection and planning appropriate vaccination strategies. The aim of the current work was to assess serological protective titers against all three polioviruses in the general population of Florence. Methods: A convenience sample of 328 sera, collected in 2009 in Florence (Central Italy) was analyzed. Samples were considered protective if neutralizing antibodies were detected at dilutions ≥1:8, according to the WHO protocols. Results: The immune coverage was 75.3%, 69.2% and 46% for PV1, PV2 and PV3, respectively. The protective titers of neutralizing antibodies were generally higher in children up to 14 years of age, with 74.4% (PV1), 75.6% (PV2) and 56.7% (PV3) of seroprevalence. From the age of 11 years, most of the study subjects were seronegative for PV3. Conclusions: In a polio-free country with strong migration pressures, such as Italy, our results bring clear support to the recent recommendation of Italian health authorities to introduce a fifth dose of IPV vaccine in adolescence all over the country.

Immunogenicity of Viral Vaccines in the Italian Military

“…The vaccine’s immunogenicity has been confirmed to be very high, as already described [ 53 ]. No post-vaccine case of HAV infection in the Italian military has been described, despite the military representing professional travelers and HAV being recognized as the biggest threat for travelers [ 19 ], thus allowing to confirm a very high vaccine-induced protection. A significantly better response was observed in subjects with low rather than high baseline antibody levels, as already observed for quadrivalent meningococcal polysaccharide [ 27 ] and for tetanus/diphtheria [ 28 ] vaccines.…”

“…These individuals showed specific antibodies at a titer of 1:4, which is considered just as protective [ 31 ]. Considering that in Italy, the compulsory polio vaccination for infants was modified from OPV to a transient regime of OPV/IPV and then IPV only at the end of the last century [ 19 ], we may argue that the baseline high level of protection could be a consequence of priming immunization at infancy with four doses of Sabin’s OPV, which was present in the Italian infant schedule until 1998. The level of baseline protection observed here is markedly higher than that found in an Italian population whose blood was collected in 2009 [ 19 ], approximately in the same time period of the current study.…”

“…Up until the end of the last century, the polio vaccine used for Italian infants was the live trivalent Sabin’s vaccine (oral polio vaccine (OPV)), then replaced in 2003 by the Salk’s trivalent inactivated polio vaccine (IPV) [ 19 ]. In the military, a booster of IPV was introduced in 1998 in the compulsory vaccine schedule of permanent staff for possible deployment abroad [ 12 ].…”

Ethical Issues in Mandatory Vaccination

“…In 2010, a survey on mandatory vaccination in Europe was conducted and information was collected from all 27 EU Member States, Iceland and Norway. Out of total, 15 countries did not have any mandatory vaccinations; the remaining 14 had at least one mandatory vaccination included in their programme [28]. But there are counties like Italy, who have moved from compulsory to voluntary immunisation programme in certain regions that have reached the herd immunity, while providing effective monitoring of the incidence of communicable disease [29].…”

Why Infants Rarely Die of COVID-19 and Morbidity and Mortality Rates Vary by Location: Pneumococcal and Hib Vaccinations as Possible Means to Mitigate Future Pandemics

“…(Storhaug, et al, 2017); @@ (Milk Consumption, 2020); & Spain and Belgium use PCV7 resulting in reemergence of pneumococcal pneumonias (Arencibia Jiménez, et al, 2014;Ciruela, 2018;Desmet, et al, 2018); * Gervaix, et al, 2014;^ Mereckiene, 2017;+ WHO, 2020;> Blank, et al, 2018; # estimated from accumulated yearly vaccinations. Austria (Richter, et al, 2019); France (Contou, et al, 2020); Germany (Theidel, et al, 2013;Pletz, et al, 2016); Greece (Maraki, et al, 2018); US (FluVaxView;Wateska, et al, 2020;Zhang, et al, 2018;Sings, 2017;Williams, et al, 2016); UK (Tolman, et al, 2016); Australia (Hull, et al, 2019;Yang, et al, 2019;Dyda, et al, 2016); Japan (Naito, et al, 2020;Takeda, et al, 2019;Shibata, et al, 2019;Kajikawa, et al, 2019;Kumar, et al, 2014); S. Korea (Song, et al, 2013;Yang, et al, 2015;Park, et al, 2019;Yang, et al, 2020); IRELAND (Corcoran, et al, 2018); Italy (Giammanco, et al, 2018;Baldo, et al, 2016;Tozzi, et al, 2014;Fedson, 2011); Spain (Ciruela, et al, 2018;Arencibia Jiménez, et al, 2014;Fedson, 2011)…”