The following is a summary of “Neutralizing Antibody Kinetics and Immune Protection Against Herpes Simplex Virus 1 Genital Disease in Vaccinated Women,” published in the February 2023 issue of Infectious Diseases by Belshe, et al.

The Herpevac Trial for Women, which was conducted by a group of researchers, was a randomized efficacy field trial of a herpes simplex virus (HSV) vaccine adjuvanted with ASO4 in 8323 women. The study participants were selected to be seronegative for HSV-1 and HSV-2. The vaccine was found to be 82% protective against culture-positive HSV-1 genital disease, but it did not offer significant protection against HSV-2 genital disease. The efficacy against HSV-1 was associated with higher levels of antibody to glycoprotein D2 (gD2) as measured by enzyme-linked immunosorbent assay (ELISA).

To gain a better understanding of the results, the researchers measured postvaccination concentrations of neutralizing antibody (nAb) to either HSV-1 and HSV-2 from HSV-infected study participants and matched uninfected controls. Statistical modeling was used to determine whether these responses were correlated with protection against HSV.

They found that nAbs to either HSV-1 or HSV-2 were correlated with ELISA-binding antibodies to gD2. The nAb findings supported the observation of protection by higher levels of antibodies against HSV-1 infection, but the lack of protection against HSV-2 remained unexplained.

In conclusion, the protection against HSV-1 infection observed in the Herpevac Trial for Women was associated with nAbs directed against the virus, although the power to assess this was lower in the nAb study compared with the ELISA results owing to the smaller sample size.

Reference: academic.oup.com/jid/article-abstract/227/4/522/6535411?redirectedFrom=fulltext