The vaccine that protects young people from cancer

By Therese Raphael

The speed with which COVID-19 vaccines broke the link between contagion and death has put the focus back on the miracle – and the science – of vaccination. If only we also had a cancer vaccine, people have said.

But wait, we do. And now, a major study has shown just how effective it is.

In 2008, the UK began offering girls between the ages of 12 and 13 a vaccine against the human papillomavirus (HPV), which is transmitted mainly sexually and is the cause of almost all cervical cancers. . Subsequently, the vaccine was implemented in a program for older girls and, since 2019, for boys.

Using data from a population-based cancer registry collected between 2006 and 2019, the researchers – who published the study last week in the Lancet – concluded that the vaccine had a significant effect on cervical cancer rates, with a reduction of 87% in those young women who were offered the vaccine at 12 and 13 years (reduction rates were lower among those who were part of the program, since fewer young people were vaccinated and it is possible that some they had already started their sex life).

“The HPV immunization program has practically successfully eliminated cervical cancer in women born since September 1, 1995″ Concludes the study. Among the successes in vaccine development, this case should be better known.

The study’s findings highlight the urgency of making these vaccines more widely available worldwide, especially in developing countries. But it also reminds us that acceptance rates could still be higher in many countries, including the United States, and not just among girls.

There are more than 200 types of HPV common in humans; most are naturally fought by the body’s immune system, but some can cause genital warts or cancer.

Almost 40% of women become infected with HPV within two years of starting their sex lives, so there is a fairly high chance of getting it. However, vaccines do not work after they have been infected with HPV, which is why it is so important that young women get vaccinated at an early age.

In general, HPV is known to be a cause of cervical cancer, but it is also the culprit for many other cancers. In 1999, molecular epidemiologist and cancer expert Maura Gillison linked some head and neck cancers to HPV and sexually transmitted diseases.

The incidence of these cancers was increasing at an alarming rate, especially among middle-aged men who had contracted HPV decades earlier. In the United States, between 2013 and 2017, there were more than 45,000 cases of cancer associated with HPV each year; almost 20,000 of them corresponded to men.

Thanks to screening programs and vaccination, the UK has seen a large decline in the major cancer-causing HPV types in both women and men, and also a large decline in the number of young people reporting genital warts.

Since cancers develop slowly over time, the real benefits of the vaccine for disease prevention (and saving lives) should be even greater. The success of the vaccine is likely to prompt a rethinking of cervical cancer screening programs, although it is unclear whether a mid-life booster will be needed.

In 2020, the U.S. Food and Drug Administration expanded approval of Merck & Co.’s HPV vaccine, Gardasil 9 (which protects against nine different types of HPV and is also used in Britain), to include its use for the prevention of oropharyngeal (throat) diseases and other head and neck cancers. It is now approved for use in men and women ages 9 to 45, with two doses only for those who were vaccinated at a young age.

And yet, despite its success, only slightly more than half of America’s teens were up-to-date on their HPV vaccines in 2019, and only 52% of children, compared with 57 % of girls (approximately 85% of women in the UK had received both doses in 2020). As with everything in the United States, rates vary dramatically by state.

HPV vaccination is a no-brainer, so why are the rates so low? Explanations vary. Two or three doses of the vaccine could be a deterrent for some parents. Some studies have suggested that since HPV is associated with sexual transmission, doctors and parents are more reluctant to discuss it.

There are also the usual concerns about adverse effects and risks. In Britain, children are generally given the vaccine at school, which makes it much easier for parents to give their consent and not forget to do so.

In addition to the global experience with COVID, the Lancet study on the HPV vaccine is another reminder of the importance of vaccines in saving lives. When science offers us a gift, it would be good if we accepted it.