Norovirus: the current focus on a major enteropathogen

Over the past eight years, 70 countries have introduced rotavirus vaccines into their National Immunisation Programs and this has resulted in a rapid and dramatic impact on morbidity and mortality associated with all-cause and rotavirus-related gastroenteritis (GE). In Brazil, one of the worldwide early adopter countries of universal rotavirus vaccination, a significant decline in GE-related hospitalisations and deaths among infants was seen, translated into rates as high as 48% and 54%, respectively1. While a major reduction in severe rotavirus GE has been experienced by several countries where routine rotavirus vaccine was implemented, norovirus is proportionally (and gradually) becoming the leading cause of severe childhood GE cases that require hospitalisation. The current scenario would therefore highlight the importance of norovirus which, for several decades, has been well recognised as the most important cause of sporadic cases and gastroenteritis outbreaks affecting people of all ages2.