Babies clear HPV before age two: Montreal study reveals

All babies who contract the human papillomavirus prenatally clear it from their bodies within their first two years of life, according to a study conducted in Montreal.

Virtually all infected babies had cleared the virus within their first six months of life, and all had cleared it before their second birthday.

“There are a lot of unpleasant things that can happen with HPV,” explained researcher Helen Trottier, an epidemiologist at the Azrieli Research Centre at CHU Sainte-Justine and a professor at the Université de Montréal School of Public Health.

“So, we’ve always wondered if the virus could be transmitted to children, and if it were transmitted, would that be problematic?”

The data come from the Heritage cohort, which includes some 400 pregnant women who tested positive for HPV and were being monitored at CHU Sainte-Justine, CHUM, or St. Mary’s Hospital.

The babies of 200 of these women were followed for two years, and those of 75 of them were followed for five years. Only two babies had a recurrent HPV infection, meaning a negative screening was followed by a positive test at a subsequent visit.

There is very little risk of the mother transmitting HPV to her baby at the time of birth, especially if she delivers by cesarean section. But even in the case of transmission, the new study shows that the risk of the baby subsequently becoming ill is extremely low, which is reassuring for the mother.

“To our great surprise, the vast majority of HPV detected in our children in the study were eliminated, meaning very little persistence, and also very, very little recurrence,” said Trottier.

Scientists don’t really understand why a toddler’s immune system is able to destroy HPV, nor why this ability subsequently disappears. “We still have a lot of research to do to truly understand natural immunity, the defense mechanisms that allow us to eliminate it,” the researcher added.

The human papillomavirus family includes more than 100 types of viruses; while some have a low risk of causing cancer, others carry a higher risk. The virus is notably recognized as the main risk factor for cervical cancer, in addition to being responsible for about a third of head and neck cancers.

The threat should therefore not be taken lightly, emphasizes Trottier, who reiterates that vaccination remains essential.

“It’s reassuring for women and babies, but it’s still extremely important to get vaccinated because HPV is a very nasty virus,” she concluded. “But as far as the perinatal transition is concerned, it’s still reassuring.”

The findings of this study were published in the Journal of Infectious Diseases.

–This report by La Presse Canadienne was translated by CityNews