Increasing incidence of varicella hospitalizations in United States Army and Navy personnel: are today's teenagers more susceptible? Should recruits be vaccinated?

Varicella (chicken pox) is highly contagious. Although varicella virus causes a variety of conditions in children, death is rare. Unfortunately, adults tend to develop more severe disease, and mortality is 25-fold higher. Despite the fact that fewer than 10 percent of adults are thought to be susceptible to varicella, the incidence of the virus among new recruits in the US Army and Navy has recently jumped, resulting in many hospitalizations. The cost of care for varicella illnesses, prevention of transmission, and lost time is high. To plan effective public health measures, the epidemiology of varicella was evaluated by examining hospital records from the Army (1980 to 1988) and Navy (1975 to 1988). These records were compared with those of control subjects, randomly selected soldiers on active duty who did not have varicella. Rates of hospitalization for varicella increased significantly in both military services during the periods studied, and were four to eight times higher than comparable rates for the general population. About half of the patients had been in military service for less than one year. Among Army personnel, several independent factors predisposed a recruit to hospitalization due to varicella infection: young age; being black or Asian-American; being from Puerto Rico, the Caribbean, Guam, the District of Columbia, New York, or New Jersey. Among Navy personnel, risk factors associated with hospitalization for varicella were: young age; being Filipino, Puerto Rican, black, or non-white; being from the Philippines, Puerto Rico, New York, New Jersey, California, Florida, or another country. The reasons why particular races and particular places of origin are associated with increased susceptibility to varicella are unclear. The results suggests that the incidence of varicella is indeed increasing for unknown reasons related to increased susceptibility of young adults. The military services would likely benefit from preventively vaccinating new military personnel, once more is known about the effectiveness of varicella vaccine in adults. (Consumer Summary produced by Reliance Medical Information, Inc.)