Rotavirus infections can be devastating for infants and young children, causing inflammation of the stomach and intestines leading to severe diarrhea, and often abdominal pain, fever, and vomiting. But a study published this week in the Journal of Infectious Diseases by researchers with the Centers for Disease Control and Prevention (CDC) has found that rotavirus may infect many more older children and adults than previously thought—and that vaccinating infants may protect the older groups as well.
Rotavirus vaccines were introduced and recommended for infants in 2006, and can prevent 85 percent or more of severe cases. Before the current vaccines, rotavirus was the leading cause of severe diarrhea in infants and small children in the U.S., causing up to 70,000 hospitalizations each year and 20 to 60 childhood deaths, according to the CDC. But by January 2008, close to 60 percent of infants were vaccinated, and that same year hospitalizations from diarrhea declined 46 percent in children under 5. Overall, the CDC estimates the rotavirus vaccines prevented 66,030 hospitalizations, and saved $204 million in averted health care costs.
Fifteen percent of the hospitalizations prevented by the vaccine program were among unvaccinated children and adults ages 5 to 24, who were not thought to be so susceptible to rotavirus infections. Older adults and seniors also saw reductions in hospitalizations. These results suggest that rotavirus infections are more widespread than previously thought. Vaccinating infants—who are most likely to spread the disease—may provide herd protection (the ability of a vaccine to protect those who aren't immunized by preventing the spread of disease in the community) and prevent infections in unvaccinated older children and adults.
The researchers say that the results could be skewed if 2008 was actually a down year for rotavirus transmission in general. But because they found the greatest declines in what should be the peak months of rotavirus transmission, the results suggest that the vaccine was likely responsible for the reduction in diarrhea and other gastroenteritis incidents.
Bottom line: Our medical experts say that childhood vaccines do far more good than harm. See our advice on the shots that children and adults need.
Infant Rotavirus Vaccination May Provide Indirect Protection to Older Children and Adults in the United States [Journal of Infectious Diseases]