Molecular characterization of rotavirus strains from pre- and post-vaccination periods in a country with low vaccination coverage: The case of Slovenia

Abstract

Rotavirus vaccination started in Slovenia in 2007 on a voluntarily basis. The vaccination rate is relatively low (up to 27%) and no increasing trend is observed. We present rotavirus genotype distribution among children hospitalized for rotavirus gastroenteritis in Slovenia. Eight consecutive rotavirus seasons were followed, from 2005/06 to 2012/13, and 113 strains of the most common rotavirus genotypes were randomly selected for molecular characterization of rotavirus VP7 and VP4 (VP8(∗)) genome segments. During the vaccine introduction period, from 2007 to 2013, rotavirus genotype prevalences changed, with G1P[8] decreasing from 74.1% to 8.7% between 2007/08 and 2010/11 seasons, replaced by G4P[8] and G2P[4], with up to 52.0% prevalence. Comparable analysis of VP7 and VP8(∗) genome fragments within G1P[8] genotype lineages revealed considerable differences for rotavirus strains circulating before and during the vaccination period. The G1P[8] rotavirus strains from the pre-vaccination period clustered in a phylogenetic tree within Rotarix®-like VP7 and VP8(∗) lineages. However, since 2007, the majority of G1P[8] strains have shifted to distant genetic lineages with lower nucleotide (88.1-94.0% for VP7 and 86.6-91.1% for VP8(∗)) and amino acid (93.8-95.2% for VP7 and 85.3-94.6% for VP8(∗)) identities to the vaccine Rotarix® strain. This change also resulted in a different deduced amino acid profile at the major VP7 and VP8(∗) antigenic epitopes.

Impact of Rotavirus Vaccination in Severe Rotavirus Gastroenteritis Outpatient Visits at Three Pediatric Primary Care Clinics in Shibata City, Niigata Prefecture, Japan

“…There are some studies reporting vaccine impact under relatively low vaccine coverage rates [11] [13] [17]- [20]. Zeller reported 35% reduction in the RV-positive rate among hospitalized patients aged less than 5 years at a university hospital in Belgium when the vaccine coverage rate was estimated as 65% [11].…”

Epidemiology of group A rotavirus infection after the introduction of monovalent vaccine in the National Immunization Program of Saudi Arabia

“…Other studies argued that the increased prevalence of G2P[4] is not directly related to selective pressure generated by RV and could be due to natural genotype fluctuation [Gurgel et al, ; Carvalho‐Costa et al, ; Matthijnssens et al, ; Gomez et al, ]. Therefore, continuous surveillance studies in the post‐vaccination period are crucial in order to collect epidemiological data on vaccine impact on RVA genetics, identify the effects of the vaccine program on circulating strains, particularly on dominant genotypes and the emergence of unusual strains, and identify possible uncommon events and genetic diversity between vaccine and circulating strains [Steyer et al, ; Velasquez et al, ; Bucardo and Nordgren, ]. In Saudi Arabia, previous studies have investigated the prevalence of RVA‐AG and epidemiological patterns of RVA genotypes in different regions during the pre‐vaccination era and data after Rotarix® introduction in the NIP are completely absent [Kheyami, ; Afifi and Nabih, ; Aly et al, ].…”

Narrowing of the Diagnostic Gap of Acute Gastroenteritis in Children 0–6 Years of Age Using a Combination of Classical and Molecular Techniques, Delivers Challenges in Syndromic Approach Diagnostics

“…However, in Slovenia, where RoV vaccine has been available and recommended since 2007, only 26.9% of children were fully vaccinated in 2009, and the proportion was even lower (19.7%) in 2013 (National Institute of Public Health, Slovenia). The vaccination coverage in our country is probably too low for major epidemiological changes in AGE but could be associated with minor changes in RoV epidemiology observed after the introduction of the vaccine (51).…”