Rubella outbreak, Fort Bragg, North Carolina, 1995: A clash of two preventive strategies

Military Medicine, Sep 1999 by Craig, Stephen C

Serum immune globulin (Baxter Healthcare, Glendale, California), 2.0 ml intramuscular, was initially offered to asymptomatic German soldiers as the best method to reduce clinical attack rates and continue with the planned military exercise. Subsequent to this decision, emergency laboratory services were contracted with Roche Biomedical Laboratories to perform rubella serology tests.

Serum samples were obtained on April 13 from all 120 soldiers in the German unit. Laboratory results for the German soldiers were obtained early on April 14 (Fig. 1). Of the 120 soldiers, all but 10 (8.3%) demonstrated anti-rubella virus IgG antibodies (titer 1.10). No subsequent serology tests were performed on the soldiers.

On April 13, serum immune globulin was administered to the four nonimmune soldiers who had not developed rashes. A physician examined these individuals daily; by April 25, none of them had developed rashes or other clinical evidence of acute rubella. An operational decision was made to retain all 10 nonimmune soldiers under quarantine at Fort Bragg, and the remaining 110 members of the unit were allowed to participate in the JRTC exercise.

Outbreak Follow-Up

All women of childbearing age in the host battalion, four of whom were pregnant, were identified and their rubella titers were checked. One dependent, an infant, who was potentially exposed to an individual with rubella, was identified and observed for the development of rubella. Confirmation of immunity was obtained for all adult women. Neither the adults nor the infant developed signs or symptoms suggestive of clinical rubella.

Public health authorities in Fayetteville (Cumberland County Health Department) were notified. An information letter was distributed for local obstetricians, family practitioners, and emergency room physicians instructing them to obtain rubella titers on potentially exposed women of childbearing age. Child care centers, both on and off the military post, in which host battalion children received care were informed and given instructions to obtain rubella titers on their employees of childbearing age.

Discussion

This outbreak and its sequelae resulted from a clash of the two rubella prevention strategies described above. The possible introduction of rubella into the Fort Bragg and Fort Polk military communities, and the risk of additional spread to surrounding civilian areas by the soldiers from a NATO country, had not been recognized previously as a threat by the military medical community at Fort Bragg.

The HPV-77 DE-5 rubella vaccine was licensed in the United States in 1969; soon thereafter, the Cendehill vaccine was licensed.5 The current live rubella vaccine, RA 27/3, was introduced in 1979 and is now the only rubella vaccine used in the United States. Although all three vaccines induce immunity in 95% of vaccinees, the RA 27/3 vaccine induces higher and longer-lasting antibody levels, provides greater resistance to reinfection, and results in fewer adverse reactions than the older vaccines. 1,4,5