Vaccine to prevent STDs also effective in preventing cervical cancer

A series of vaccines given to protect against a group of sexually transmitted diseases is highly effective at preventing cancer.

The human papillomavirus (HPV) vaccine is administered in two doses, with the first administered at age 11 years and the second six to 12 months later.

Now, two new analyses from the Cochrane Institute, regarded as the gold standard for clinical research, found that girls vaccinated before age 16 were 80 percent less likely to develop cervical cancer later in life.

Across more than 132million patients, researchers also found ‘substantial reductions’ in precancerous cervical lesions among vaccinated individuals, reducing their risk of developing the disease in later life.

Researchers said that the vaccines were not linked to serious adverse side effects and were only likely to cause minor, short-lived issues such as a sore arm.

Cervical cancer is the fourth most common cancer among women globally. About 90 percent of cases are caused by a persistent HPV infection, a virus often spread via sexual contact, that can cause mutations in cervical cells that lead to cancer.

Cervical cancer rates declined by more than half in the US between the mid-1970s to 2000s, largely due to widespread cancer screening, but, after the HPV vaccine was rolled out in 2006, among 20- to 24-year-olds, rates dropped by a further 11 percent between 2012 and 2021.

Currently, 62.9 percent of children aged 13 to 17 years are up to date on their HPV vaccinations in the US, CDC data says, compared to 61.4 percent the previous year and a record nationwide.

It is, however, below the World Health Organization’s target of 90 percent of children being vaccinated, the level that experts say is needed to stop HPV from spreading.

About 13,360 women are diagnosed with cervical cancer in the US every year, estimates suggest, while 4,320 women die from the condition.

About 42million Americans are estimated to be infected with HPV, according to the CDC, and about 13million are said to be infected every year.

The virus is spread via skin-to-skin contact, such as in oral, anal and genital sex and may cause no symptoms, although it can cause genital or anal warts. In most cases, it is cleared within two years on its own, but in some cases, it can linger in the body for decades.

About 36,000 cancers are estimated to be caused by the virus every year. The infection is also linked to cancers in the throat, mouth, vulva, penis, vagina, penis and anus. 

Dr Jo Morrison, a gynecologist in the UK who was a senior author in the analyses, said: ‘These reviews make it clear that HPV vaccination in early adolescence can prevent cancer and save lives.

‘Vaccinating boys as well as girls boosts protection for everyone. Over time, we’ll see the impact of vaccination on other cancers too, including ones that affect men.’

Dr Nicholas Henschke, the Head of Cochrane Response and a leading author in the analyses, added: ‘We now have clear and consistent evidence from around the world that HPV vaccination prevents cervical cancer.

‘An important finding was that the commonly reported side effects of the vaccine, often discussed on social media, were found to hold no evidence of a real link to vaccination.’

The reviews said social media users had linked the vaccines to paralysis, infertility, chronic fatigue syndrome and complex regional pain syndrome, or when there is a burning sensation in the arms, legs, hands or feet that does not ease, but that their analysis had not found a connection between the vaccine and these conditions.

In the first analysis, researchers analyzed data from 60 studies involving more than 157,000 participants.

They found that all HPV vaccines, such as Cervarix, Gardasil and Gardasil-9, were effective at preventing HPV infections. They also showed there were no significant side effects.

The CDC says HPV vaccines are nearly 100 percent effective at preventing infections with the virus.

The researchers said that among women aged 15 to 25 years old, those who were vaccinated had a lower risk of being diagnosed with precancerous changes in their cervix or of needing treatment for HPV-related issues. It did not give a percentage.

In the second analysis, researchers analyzed data from 225 studies involving 132million people that were carried out across the world.

They found that HPV vaccination before the age of 16 reduced the risk of cervical cancer by 80 percent. They said it also substantially reduced the risk of precancerous changes in the cervix.

In the analysis, they also noted substantial reductions in anogenital warts, warts on the genitals and anus, among those who were vaccinated before the age of 16 years compared to those in older age groups.

The study also found no evidence that HPV vaccination raised the risk of serious side effects.

Limitations to the studies were that most of the research the new studies drew from was carried out in high-income countries. Researchers said that more work was needed in middle- and low-income countries to confirm their results.

Dr Hanna Vergman, a surgeon in the US who was also a senior author on the studies, said: ‘Clinical trials cannot yet give us the whole picture on cervical cancer, as HPV-related cancers can take many years to develop.

‘That being said, the evidence from these trials confirms that HPV vaccines are highly effective at preventing the infections that lead to cancer, without any sign of serious safety concerns.’