RSV and HMPV seroprevalence in Tuscany (Italy) and North-Rhine Westfalia (Germany) in the winter season 2009/2010

摘要

RSV and HMPV are the major contributors to mild tosevere respiratory infections in all age groups. Most infectionsare recognized in children and frequent re-infectionsare observed for both viruses [reviewed in1,2]. The seroprevalencefor both viruses was described to be age . dependent,and the rate of seropositive individuals wassignificantly higher in subjects older than 10 years. Surprisingly,in a recent large study concerning the HMPV seroprevalencein a German cohort of Bonn,3 the neutralizingimmune response was shown not to correspond to theoverall seroprevalence described in previous studies.4,5 Takingthese data into account, we hypothesised that this discrepancycould be due to geographical differences,consequently, we prospectively analysed the seroprevalencein children against both viruses during the winter . springseason 2009 . 2010 in two different regions of Europe,Northrhine-Westfalia, Germany (85 serum samples), andTuscany, Italy (86 serum samples). Unlike the study ofMatsuzaki et al.,4 who used a neutralization assay, and Liuet al.,5 who used an in-house recombinant ELISA, theserum samples in the present study have been investigatedfor the presence of antibodies by indirect immunofluorescence,as previously described.6 It appears that only marginaldifferences were observed in the seropositivity rates ofthe corresponding groups aged 1-5 years (mean age 2,5 forItalian children and 1,5 for German children) and 6.10 years (mean age 7,5 for all the children), respectively, ofthe different geographic provenances (Table 1). It is worthyto note that the sera were drawn from infants older than6 months, in order to exclude the possibility of an overestimationof seropositives due to the presence of specificmaternal antibodies. In the youngest group, the HMPVseroprevalence in the two countries was indistinguishable(48A8%), whereas the RSV seropositivity rate was slightlyhigher in the German group, but without a significant difference(P > 0A05). In the oldest group, the seropositivityrate was similar for both the viruses (P > 0A05).