HPV vaccines and pregnancy: the situation in early 2012

Vaccines against human papillomavirus (HPV) types 6/11/16/18 (Gardasil) and 16/18 (Cervarix) are non-viable vaccines composed of recombinant HPV proteins. As a precaution, they should not be given during pregnancy. However, some women are vaccinated shortly before conceiving or early during an undiagnosed pregnancy. What are the risks for the unborn child exposed in utero to these vaccines? We examined data available in late 2011. After in utero exposure to the HPV 6/11/16/18 vaccine during the first trimester, animal studies, only conducted in rats, showed no increase in the risk of malformations. Five clinical trials and the latest annual update of the Pregnancy Registry for Gardasil, released in 2010 and including more than 1000 vaccinated pregnant women, showed no particular pattern of malformations with the quadrivalent vaccine. A few reports of very rare abnormalities are troubling, but they do not clearly implicate the vaccine. Most data on the HPV 16/18 vaccine come from two clinical trials comparing this vaccine with hepatitis A vaccine or placebo vaccination. Fewer than 400 pregnancies exposed to the HPV 16/18 vaccine have been studied. The rate of congenital malformations was similar to that in the control population. In practice, there are few data on exposure to HPV vaccines during the first trimester of pregnancy. There are more, relatively reassuring, data on the HPV 6/11/16/18 vaccine. Women who are vaccinated just before conceiving or early in pregnancy should receive appropriate information. Active pharmacovigilance must continue.