Vaccine cuts rate of HPV infection, precancerous lesions - Medical News Today

Posted: 05 Jul 2019 12:00 AM PDT

Researchers have attributed a substantial drop in human papillomavirus (HPV) infections to the HPV vaccine. Now, they are waiting to see if it will have the same impact on the rates of cervical cancer.

healthcare professional giving a young woman a vaccine

Vaccines have slashed the number of HPV infections, new research suggests.

Just over a decade ago, healthcare professionals introduced a new vaccination that aimed to prevent recurring infections of certain types of HPV. These infections can, if a person does not receive treatment, lead to cervical cancer.

According to the National Institutes of Health (NIH), this form of cancer is the third most common among women.

The invention of the Pap smear significantly reduced deaths from cervical cancer in the United States, but the condition is still responsible for around 300,000 deaths worldwide every year.

Researchers and healthcare professionals hope that the HPV vaccine will significantly reduce the prevalence of cervical cancer. But it is still too early to determine its potential effectiveness.

However, researchers are able to measure the effects of vaccination programs on the prevalence of HPV infection. They can also measure the prevalence of precancerous lesions caused by the virus before and after the implementation of the vaccine.

These lesions can appear in several places, including the cervix, mouth, vagina, anus, and penis.

How the vaccine works

HPV, on the whole, has been tricky to combat. There are more than 100 known strains of the virus. Around 40 of these can be sexually transmitted, and approximately 15 have the ability to cause cancer.

The existing vaccine targets the two strains responsible for 70% of cervical cancer cases, HPV-16 and HPV-18, along with five other high-risk strains. One version of the vaccine also protects against strains that cause 90% of genital warts cases.

Doctors recommend the vaccine for children ages 11–12. For those who have yet to receive the vaccine, doctors tend to administer it in women up to age 26 and in men up to age 21, though some men may benefit from receiving it up to age 26.

To see how effective these vaccines have been, a group of researchers from the Centre de Recherche du CHU de Québec—Université Laval, in Canada, have analyzed 65 studies from 14 countries that have an HPV vaccination program. Their findings appear in The Lancet.

To be eligible, studies had to have been published between 2014 and 2018. They also needed to compare pre- and post-vaccination prevalence of at least one of the following: HPV infections, anogenital warts, or precancerous cervical lesions.

The resulting data came from 60 million people. The researchers carried out an analysis to find the potential impact of the vaccine 1–4 years and 5–8 years after vaccination. They broadened this time frame to 9 years when studying the effect on lesions.

The team then compared data from countries with a vaccination coverage of at least 50% and those with lesser coverage, as well as data from countries that vaccinated at multiple ages and those that vaccinated within only one age range.

A significant reduction

The researchers found that for girls ages 13–19, HPV infections had reduced by 83%. The reduction was slightly less significant, 66%, among women ages 20–24.

The team noticed a similar pattern for both anogenital warts and precancerous cervical lesions. For the former, the analysis revealed a reduction of 67% among girls ages 15–19 and 54% among women ages 20–24.

Furthermore, the study recorded a 51% reduction in legions among girls ages 15–19, along with a 31% drop among women ages 20–24.

There also appears to be a benefit to males. Cases of anogenital warts in 15- to 19-year-old boys decreased by 48% and 20- to 24-year-old men saw a reduction of 32%.

When it came to comparing results from high- and low-coverage countries, the researchers concluded that high-coverage countries saw the most benefits. This was also the case for countries that vaccinated females in more than one age group.

Although these figures are impressive, not every country is experiencing the same drop in numbers. Some do not vaccinate at all, while others have lower rates due to unsubstantiated fears that the vaccine causes illnesses.

But, as lead author Mélanie Drolet, Ph.D., explains, "These reductions are a first sign that vaccination could eventually lead to the elimination of cervical cancer as a public health problem."

"We are now trying to determine when elimination could be achieved and which vaccination and screening programs could help us achieve it faster."

Mélanie Drolet, Ph.D.

It may still be necessary to develop a vaccine that works against a wider range of HPV strains. In the meantime, facilitating global implementation of the current HPV vaccine is likely to be the next vital step.

Teenage Boys in The UK Will Now Be Vaccinated Against Cancer-Causing HPV - ScienceAlert

Posted: 10 Jul 2019 12:00 AM PDT

Since 2008, young teenage girls in the United Kingdom have had access to a free HPV vaccine. This September, over a decade later, the National Health Service (NHS) will be extending the same benefit to teenage boys.

The human papilloma virus (HPV) is the cause of most cervical cancers in women, but this sexually transmitted infection can just as easily infect men. The virus has been linked to five percent of all known cancers, including anal cancer, mouth and throat cancer, and even penile cancer.

In the last decade or so, as cervical cancers have dropped dramatically worldwide, oral cancers have begun to surge upwards, especially among men. In fact, these are now the fastest-increasing cancers in some areas of the world.

So far, several countries - including Australia, Canada, the United States, Norway and Italy - have responded to this increase by vaccinating everyone against cancer-causing HPV, regardless of their sex or sexual orientation.

But in the last few years UK health officials have argued that giving boys a free HPV vaccine is not cost effective, and that if women are vaccinated they inevitably won't pass it on to their male sexual partners.

Critics have been quick to point out that this assumes complete coverage and completely overlooks certain sexual orientations. Last year, as a result, the NHS extended the HPV vaccine program only to those men who have sex with other men - a fairly ridiculous design given that boys are vaccinated at the age of 12 or 13 when they might not know who their future sexual partners will be.

"HPV does not discriminate, it can affect everyone, yet there are still many harmful myths and stigmas surrounding it," said Robert Music, the chief executive of Jo's Cervical Cancer Trust, according to The Guardian.

"This is why a universal vaccination programme is so important, as not only will it normalise this very common virus and reduce existing inequalities, it will protect many more people from developing cancer and save lives."

Today, it seems the NHS has at last been convinced. In 2018, the Joint Committee on Vaccination and Immunisation (JCVI) recommended a 'gender neutral' vaccine programme to the NHS, given the recent rise in oral cancers and systematic reviews that show how effective male vaccination can be.

Public Health England (PHE) even claims that the updated program will prevent more than 100,000 cancers across the UK by 2058, and 50,000 of these would be for non-cervical cancers.

"This universal programme offers us the opportunity to make HPV-related diseases a thing of the past and build on the success of the girls' programme," said Mary Ramsay, the Head of Immunisation at PHE.

"Offering the vaccine to boys will not only protect them but will also prevent more cases of HPV-related cancers in girls and reduce the overall burden of these cancers in both men and women in the future."

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