The first long-term study conducted into the HPV vaccine confirm it is almost 100 percent effective at protecting men from developing oral cancer.

The treatment was approved to the market in 2006 to prevent women from getting cervical cancer but experts haven't been able to fully examine its effect over time.

Now, the results are in from a three-year study on the effects - the longest investigation ever on HPV.

It confirmed that there was no trace of cancer-linked strains of HPV among men who received the vaccine - whereas two percent of untreated men had a potentially cancerous strain.

Another study, also released today, found the jab makes it next to impossible for vaccinated children to develop genital warts from the STI in their late teens and 20s.

Despite a multitude of interest and research, these are the first substantial studies to confirm the vaccine's ability to protect people from the STI and diseases that can stem from it.

The HPV vaccine does protect against infection, preventing genital warts, and possibly against oral cancer in men, according to new studies

WHAT IS HUMAN PAPILLOMA VIRUS? HPV is the most common sexually-transmitted infection. In fact, almost every sexually active man or woman will get it during their lifetime. It is spread through sex and oral sex with someone who has the virus, regardless of whether they show symptoms. Many people never show symptoms, and the majority of cases go away without treatment. However, it can sometimes cause genital warts and/or cancer. Symptoms can arise years after infection. Around 99 per cent of cervical cancer diagnoses are related to infections like HPV. HPV can also cause cancers of the throat, neck, tongue, tonsils, vulva, vagina, penis or anus. Often, the cancer does not develop until years after a patient was infected with HPV. Source: CDC Advertisement

Human papillomavirus (HPV) is the most common sexually-transmitted disease in the US, with approximately 80 million people currently infected.

Although most infections disappear on their own, without even displaying symptoms, some strains can lead to genital warts and even cancers, including prostate, throat, head and neck, rectum and cervical cancer.

Approximately 28,000 cases of cancer caused by HPV are diagnosed annually - most of which would have preventable with the vaccine, the CDC says.

The vaccine was first introduced with the main goal to prevent cervical cancer in women, but only about half of those eligible are getting the shots.

The study on HPV vaccines leading to oral cancer in men was led by Dr. Maura Gillison of the University of Texas MD Anderson Cancer Center.

It was the first research done on whether the vaccine might prevent oral HPV infections in young men, and the results suggest it can.

The data was compiled from 2,627 men and women ages 18 to 33 years in a national health study from 2011 to 2014.

The results in men were striking - no infections in the vaccinated group versus 2.13 percent of the others.

The two-dose vaccine study on genital warts was conducted by medical experts at the Boston University School of Medicine and examined the number of shots given to patients.

They concluded that girls given two or three jabs prevented better against genital warts compared to those given one or no jabs.

There were similar results in the two and three jab test subjects, which experts concluding two counts of the vaccine were enough.

Rebecca Perkins, an obstetrician and the lead author of the Boston study, said: 'This study validates the new recommendations and allows us to confidently move forward with the two dose schedule for the prevention of genital warts.'

HPV is the most common sexually-transmitted infection. The vaccine was first introduced with the main goal to prevent cervical cancer in women, but only about half of those eligible are getting the shots

40,000 HPV-LINKED CANCERS DIAGNOSED A YEAR, CDC SAYS Figures released in July showed a dramatic climb in diagnoses of cancers linked to HPV. An average of 39,000 cases were diagnosed each year between 2008 and 2012, the CDC reported. That was a leap from 33,500 a year between 2002 and 2007. Almost 80 percent of cases in the last five years were directly attributable to HPV, including 19,200 diagnoses for female and 11,600 for males. The most common HPV-related diagnoses in women were cervical cancers. For men, mouth and throat cancers were the most common. The CDC estimates that more than 28,000 of these diagnoses could have been blocked by the HPV jab. 'Full vaccination coverage of the U.S. population could prevent future HPV-attributable cancers and potentially reduce racial and ethnic disparities in HPV-associated cancer incidence,' the authors wrote. 'Ongoing surveillance for HPV-associated cancers using high-quality population-based registries is needed to monitor trends in cancer incidence that might result from increasing use of HPV vaccines and changes in cervical cancer screening practices.' Advertisement

Although HPV is very common and a majority of cases go away without treatment, the infection does have several other risks.

Oral infections are blamed for 70 percent of cancers in the mouth and back of the throat. About 11,600 of these occur each year in the U.S. and rates are rising five percent per year.

They're four times more common in men than women.

There are now more mouth and throat cancers caused by HPV in the U.S. each year than there are cervical cancers.

Oral sex is the main risk factor for getting an HPV infection in the mouth or throat, Dr Gillison said. While 'oral sex does not give you cancer,' the infection in rare cases can develop into cancer over many years, she explained.

The vaccines are recommended mostly for young people, ideally before they're exposed to HPV.

Merck's Gardasil is approved in the U.S. for females nine through 26 to prevent cervical, vulvar, vaginal and anal cancers and genital warts.

For males ages nine through 26, it's approved for preventing anal cancer and genital warts.

A newer version of Gardasil that includes more HPV virus types is approved for males nine through 15.

GlaxoSmithKline's Cervarix vaccine is approved for females nine through 25 to prevent cervical cancer.

All require two or three shots, depending on age.

When the vaccine was first introduced, it faced a wave of backlash from conservative parents who thought the shot would encourage children to be promiscuous.

Michele Bachmann led a fierce campaign against the vaccine and urging senators to block the jab's approval, claiming there was evidence it led to mental disorders.

Some schools began to require children to have the vaccine, including those in the District of Columbia and Virginia. Rhode Island schools require both girls and boys to get the jabs.

Nearly half of US states have proposed school-entry requirements for HPV vaccination without success since 2006.

Parents were the least likely to agree with HPV vaccine school-entry requirements if they lived in the Midwest, and they were most likely to agree if they lived in the Northeast.

In the UK, all girls aged 12 to 13 get the vaccine as part of the NHS childhood vaccination program, and it's usually given to girls in year eight.

The treatment in England is two injections to the arm spaced at least six months apart. Girls who began vaccination before September 2014 receive three injections.