Vaccinating young children to protect them from rotavirus also appears to give indirect protection to adults, say researchers whose findings appeared today in Clinical Infectious Diseases.
Symptoms of rotavirus infection, the most common cause of severe gastroenteritis in infants and young children, include vomiting and diarrhea, which can cause severe and potentially fatal dehydration. Before the introduction of the pediatric rotavirus vaccine in 2006 in the United States, rotavirus was responsible for more than 400 000 annual doctor visits, 200 000 emergency room visits, up to 70 000 hospitalizations, and up to 60 deaths in children younger than 5 years. Worldwide before the vaccine’s introduction, rotavirus infection caused an estimated 2.4 million hospitalizations and more than 450 000 deaths in young children.
The rotavirus vaccine is given to infants in a series of shots over the first 6 months following birth. Analysis of hospital discharge data from 18 states after introduction of the vaccine found the hospitalization rates for gastroenteritis resulting from all causes for children younger than 5 years for 2007 and 2008 were 16% and 45% lower, respectively. Emerging evidence also suggests that vaccinating infants provides indirect protection against rotavirus (by reducing exposure to circulating virus) in older, largely unvaccinated children, but whether unvaccinated adults are similarly protected remained in question.
Now evidence of such protection comes from an analysis by Chicago researchers, who looked for the presence of rotavirus in 3530 adult stool samples prospectively collected at Northwestern Memorial Hospital between 2008 and 2010 and in samples collected in 2006 and 2007 (before rotavirus vaccination of US infants became widespread). The researchers found the prevalence of rotavirus infection among adults nearly halved, from 4.35% in 2006-2007 to 2.24% in 2009-2010.
Although the effects of rotavirus infection in adults are not as serious as those in young children, it still causes an estimated $152 million in adult inpatient hospital charges annually, suggesting infant vaccination will be more cost-effective than previously believed. “By improving the health of children, we indirectly improve the health of adults,” said lead author Evan J. Anderson, MD, in a release.