Epidemiology and prevention of rotavirus infection: an underestimated issue?

Rotaviruses (RVs) were found to cause human disease in 1973. They are the leading cause of severe gastroenteritis in infants and young children of <5 years of age worldwide and they are the cause of approximately half a million deaths each year. The impact of the disease on families and society (increased health care costs, lost productivity) is extremely significant and the incidence of gastroenteritis (RVGE) is similar both in industrialized and in developing countries. Virtually, all the children will be Infected by RVs before the ages of 3-5 years with the highest incidence rate registered between 6-24 months of age while the greatest risk for developing severe disease by RV occurs under 12 months of age. Clinically, the infection can vary from asymptomatic and sub clinic forms, which are more common in older children and adults, to acute gastroenteritis with fever, vomiting and self-limiting watery diarrhea which persist for 3 to 8 days. Severe forms with profuse diarrhea accompanied by vomiting and fever with risk of dehydration not adequately and rapidly correct can be fatal, mainly in developing countries. Hygienic-sanitary measures are unable to limit the diffusion of this infection and vaccination at present seems the only effective system to reduce the burden of the disease, human and economic costs related to RVGE. Since the 1980s research has focused on the development of RV vaccines. Vaccines against RV are efficacious, and underwent extensive safety trials (involving more than 130,000); no association with intussusception was detected and in four years since they were licensed a substantial reduction in the rates of RVs hospitalization and deaths for RVs infection have been observed both in developed and less-developed countries. It has been also described in different studies that herd immunity can be induced by RV vaccines (as an indirect effect) by reducing the risk of unvaccinated persons to be infected. Thus, introduction of the vaccine into countries immunization programs is likely to have a greater effect than that predicted on the basis of the efficacy trials. The worldwide epidemiological impact of RV infection pointed the development of safe and effective vaccines against RVs as a public health priority. The great economical burden on health care systems and families suggests the importance of monitoring circulating strains, establishment of systems for surveillance and implementation of universal newborns vaccination.