Clinical efficacy of a herpes simplex subunit vaccine.

A DNA-free herpes simplex type 2 subunit vaccine was administered to 18 volunteers without past evidence of herpes simplex type 1 (HSV 1) or herpes simplex type 2 (HSV 2) infection, to 44 patients with severe recurrent genital HSV 2 infection, and to 15 patients with severe oral type 1 HSV recurrences. The vaccine elicited both humoral and cell-mediated immunity in 97% of the subjects without past HSV infections and boosted significantly the cell-mediated immunity and antibody titers in almost all the patients with recurrent HSV 1 or HSV 2. The vaccine elicited particularly the production of complement-dependent cytotoxic antibodies in 96% of the patients with recurrent HSV 2 infections. This might, at least partly, explain the clinical efficacy of the vaccine. Indeed, we observed a significant decrease (t test, p less than 0.01) in the attack rate of the recurrences and also a significant shortening of the time needed to complete healing of the lesions (t test, p less than 0.01).