The short versionIn 24 adults who already have recurrent genital herpes, two experimental vaccines given alone or together were safe and strengthened immune responses against HSV‑2. The trial was too small to show whether they reduce outbreaks.
Therapeutic vaccines aim to help people who already have HSV‑2 by training the immune system to keep the virus in check. This study, published in Vaccine, tested two candidates in people with a history of recurrent genital herpes.
The two vaccines
- HSV529: a disabled HSV‑2 that can enter cells but cannot copy itself.
- G103: three HSV‑2 proteins (gD2, UL19 and UL25) combined with an adjuvant called GLA‑SE that strengthens the immune response. This was G103’s first test in people.
How the trial worked
24 adults (11 men and 13 women) were randomly assigned to six groups receiving different doses and combinations, or placebo, on a two-dose schedule. Some groups received HSV529 followed by G103; others received both at the same visit, in different arms.
What they found
- Safety: no immediate unexpected reactions. Most injection-site reactions were moderate, with one case of severe swelling. Headaches and muscle aches occurred regardless of the adjuvant dose. The authors judged the safety profile acceptable.
- Immune response: all participants started with some immunity to HSV‑2. After the first G103 dose, T cells against all three vaccine proteins increased, most strongly for gD2. Antibodies, including virus-neutralizing antibodies, rose most for UL25.
What to keep in mind
This is an early safety and immune-response study. With only a few people in each group, it cannot tell us whether either vaccine reduces outbreaks or viral shedding. That would need a larger and longer trial.
SourcesThis is an independent summary for a general audience, not medical advice.