The risk of vertical transmission of HSV from mothers with a primary HSV infection to fetuses is about 25–50% and decreases to less than 3% in women with a recurrent HSV infection due to placental protecting IgG antibody.18 If needed, cesarean section should be considered to avoid newborn infection by the birth canal.5 Similar to CMV infection, different seasonal prevalence observations were made in HSV1‐IgM. Here, CD40LG is linked to infection.