CNRS researchers analyzed the evolution of human papillomavirus (HPV) infections, involved in cervical cancer, in nearly 200 women.
- Nearly 20% of women under the age of 25 are affected by human papillomavirus (HPV) infections. Although most cases disappear spontaneously within two years, without symptoms, some infections can persist and cause serious complications, such as cervical cancer.
- The results show that non-persistent infections, which last less than 24 months (beyond that we speak of chronic infection), reach a viral load plateau approximately two months after infection, which persists for 13 to 20 months before a rapid reduction.
- The HPV vaccine is now recommended for girls and boys aged 11 to 14. If the vaccine is administered before age 14, it is estimated that it prevents up to 90% of HPV infections that cause cancer.
Human papillomavirus (HPV) infections are very widespread, particularly among young women: almost 20% of those under 25 are affected. Although most cases disappear spontaneously within two years, without symptoms, some infections can persist and cause serious complications, such as cervical cancer. Each year, HPV is responsible for more than 600,000 new cases of cancer worldwide, including 6,400 in France, according to the National Cancer Institute.
While a vaccination campaign is due to begin this Wednesday, January 22 in all private and public colleges in Paris, until April 11, a new French study, published in the journal PLOS Biologysheds new light on the differences between acute and chronic infections, an essential element for improving treatment and prevention strategies.
A viral load plateau two months after HPV infection
To understand the dynamics of infection, the team led by Samuel Alizon, researcher at CNRS, followed 189 women aged 18 to 25 over a maximum period of 24 months. A press release specifies that participants were examined every two months, which made it possible to collect precise data on viral load and immune markers.
The results show that non-persistent infections, which last less than 24 months (beyond that we speak of chronic infection), reach a viral load plateau approximately two months after infection, which persists for 13 to 20 months before a rapid reduction. “The majority of HPV infections are halfway between acute infections which rise and fall very quickly, such as flu or Covid, and longer chronic infections.underlines Samuel Alizon in the columns of World.
Why does the infection persist for several months? “HPV infects stem cells at the base of the epithelium [qui tapisse notamment la muqueuse vaginale]and, when these cells differentiate and die on the surface of the epithelium, the virus is released, explains the researcher. So the infection lasts as long as these stem cells are alive, it’s a bit of a reservoir for the infection.” Different mechanisms then explain the recovery of the majority of patients, starting with the activation of the innate immune response.
Strengthening vaccination coverage among young people
While vaccination against human papillomaviruses (HPV) prevents up to 90% of HPV infections, vaccination rates among French adolescents remain well below the objective of 80% by 2030 set by the ten-year strategy to combat HPV. cancers 2021-2030, according to Health Insurance.
The vaccine is now recommended for girls and boys aged 11 to 14, with the administration of two doses spaced at least five months apart. A catch-up is possible from 15 to 19 years old, with three doses. Since the start of the 2023 school year, this vaccination is offered at college in order to strengthen vaccination coverage among young people. If the vaccine is administered before the age of 14, it is estimated that it prevents up to 90% of HPV infections that cause cancer. An effectiveness which drops to 40% after 17 years.
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