Nearly all newborns who contract human papillomavirus in the perinatal stage will eliminate the virus in the first six months of life, with very little persistence or recurrence, according to a new Canadian study published today in the Journal of Infectious Diseases.

Led by Helen Trottier, an epidemiologist at the Centre de recherche Azrieli du CHU Sainte-Justine and a professor at Université de Montréal’s School of Public Health, the study shows that, on average, babies who contracted HPV at birth were virus-free in less than four months.

All had eliminated it within 24 months, the study found.

This data comes from the HERITAGE cohort, which includes 422 HPV-positive pregnant women receiving care in one of three Montreal hospital centers (CHU Sainte-Justine, CHUM, and St. Mary’s Hospital).

Two hundred of these women’s newborns were monitored over two years, and an additional 75 of these children were monitored for five years. Only two babies had recurring HPV infections – that is, a negative test followed by a positive test at a subsequent visit.

One baby tested positive at two consecutive visits and is therefore considered to have had a persistent infection. The team also discovered new cases of HPV infection, even in babies who had not contracted it at birth.

In other words, at some point during the two years of monitoring, 26 children had acquired a genotype of the virus that had not been detected before.

“This may be transmission from the mother after birth, or from the father or another person caring for the child, through bathing or diaper changes for example,” Trottier explained.

Nonetheless, all the newborns in the cohort who contracted HPV had eliminated the virus by the age of 2.

“This data is very encouraging,” says Eméra Alice Bénard, an UdeM master’s student and first author of the study. “We now know that it’s quite unlikely for a mother to transmit the virus to her baby during pregnancy or childbirth. Even if transmission occurs, the risk of the baby contracting a severe or persistent form of the virus is very, very low. This will be reassuring to pregnant women who have been diagnosed with HPV.”

Despite these positive results, Trottier emphasizes the importance of vaccination to avoid HPV-related complications in adults, such as genital or oral cancers.

The virus is very common in people of reproductive age and is recognized as the primary risk factor for cervical cancer, in addition to explaining about one-third of all head and neck cancers. Several studies have also linked HPV infections to an increased risk of premature birth.

“Vaccination is a very effective measure for preventing HPV," said Trottier. "Even if the risk is low for babies, it is imperative to do it for oneself."

Source: Universite de Montreal