Acute gastroenteritis hospitalizations after implementation of universal mass vaccination against rotavirus

Norovirus strains among children aged 0–18 years hospitalized with acute gastroenteritis in Estonia 2015–2016

“…To our knowledge, this study is the first to report NoV strain data from Estonia during the one and half year time period immediately after RVUMV implementation in 2014, when a significant increase in NoVGE hospitalizations was reported. 7 Our study reports high genotypic diversity of NoV strains cocirculating in Estonia with 9 genotypes and 21 dual types detected.…”

“…To our knowledge, this study is the first to report NoV strain data from Estonia during the one and half year time period immediately after RVUMV implementation in 2014, when a significant increase in NoVGE hospitalizations was reported 7 …”

“…Although the occasional increase in NoVGE has been associated with the emergence of novel viral strains 24,25 it was not seen by us nor other countries that have demonstrated an increase of NoVGE among hospitalized children post‐RVUMV. GII.4 has remained the most prevalent strain post‐RVUMV with some increase in GII.7, GII.3, GII.1, GII.2, and GI.3 circulation over seasons, most likely representing natural fluctuations 5–7,18,26 …”

“…31 The authors, however, believe that seasonal variations in NoVGE are attributed to the factors that enhance virus transmission and maintain its circulation in a population rather than by specific strains, vaccination programs targeting other gastroenteric viruses, or weather. 15 NoVGE is an important cause of hospitalization [5][6][7] and improving knowledge of prevailing NoV strains across the EU countries should be invested in the efforts to develop an effective NoV vaccine on a priority basis. Despite many challenges regarding vaccine development like duration of vaccine-induced immunity, the extent of crossprotection between different genotypes, and differences in strain distribution 31 several vaccines are in clinical trial phase including intranasal GI.1, intranasal GI.1/GII.4 bivalent vaccine, intramuscular GI.1/GII.4 bivalent vaccine, trivalent vaccine that incorporates GII.4, GI.3 and rotavirus recombinant VP6 protein.…”

“…A stool sample was collected at the very first opportunity after admission or thereafter until discharge. Collected stool samples were tested for the presence of NoV as well as other common enteric viral pathogens, including rotavirus and adenovirus 41/42, as part of a surveillance study 7 . All NoV antigen‐positive samples were selected for genotyping.…”