Women who received the HPV vaccine up to age 20 can still be protected against the virus, a new study claims.
Researchers from Kaiser Permanente in California say girls who missed the recommended series between ages 11 and 12 can still be immunized against viral strains much older than previously thought.
However, after 21, the vaccine is not effective likely because women have had enough sex to be exposed to HPV and won’t benefit from inoculation.
While the jab was only recommended for young girls who were likely not yet sexually active, several studies have shown that the virus can be contracted from simply coming into contact with an unsanitized surface and scientists say it’s better to get the vaccine as early in your teens as possible.
A new study has found that catch-up vaccines – for those who missed the recommended series between ages 11 and 12 – are effective in women up to 20 years old (file image)
HPV, short for Human papillomavirus, is the most common STI in the US, affecting around 79 million people. It has been linked to numerous cancers – including prostate, throat, head and neck, rectum and cervical cancer.
Since the HPV vaccine was introduced in 2006, 79 countries and territories have implemented a publicly funded national HPV vaccination program.
In the US, the vaccine is offered in two or three doses over the course of six months to girls who are between 11 and 12, with a catch-up series recommended no later than age 26.
In the UK, all girls between ages 12 and 18 are offered free vaccination against HPV over six to 12 months, but until recently it wasn’t offered to boys.
Last month, government officials finally announced that the NHS will inoculate 12- and 13-year-old boys as well after a prevalence of head and neck cancers were seen in men.
Ireland followed suit and also announced that the HPV vaccine will be given to boys in 2019.
For the study, researchers analyzed cases for CIN2+ or CIN3+, which is the abnormal growth of cells on the cervix and could lead to cervical cancer.
The team looked at more than 4,300 women with CIN2+ or CIN3+ and controlled by including more than 21,000 women without the cell growth.
Close to 3,000 of the women had received at least one vaccine dose between 2006 and 2014.
The team found that the catch-up vaccine was effective in girls between ages 14 and 20 if they received the full three doses.
However, the researchers said no protection was seen in women who received their first dose at 21 years old or older.
The authors admit they are not sure why age 21 is the cut-off point for effectiveness but theorize that it may be the same reason why the vaccine is only FDA-approved: that women and men have had enough that they’ve been exposed to HPV and won’t benefit from a vaccine.
‘In comparison to other countries, HPV vaccine uptake in the US has been relatively low,’ said lead author Michael Silverberg, a research scientist with Kaiser Permanente Northern California’s Division of Research.
‘Our findings show that girls and women who did not receive the full vaccine series at age 11 to 12 can still benefit from significant protection if they receive the full three doses of vaccine by the age of 20.
‘The evidence suggests that protection is strongest the earlier the vaccine is initiated.’
WHAT IS HUMAN PAPILLOMAVIRUS?
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 percent 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.
The authors said that of the women in the study, just 23 were diagnosed with cervical cancer.
Only three of them had been vaccinated against HPV but they were all 21 years or older when they were given the first dose.
When the Gardisil vaccine was introduced to the market in 2006, it was the only HPV jab available and only given to girls before it was extended to boys in 2009.
Many medical professionals administering the first dose declared it could only be given to virgins because they were the least likely to be exposed to HPV strains.
The thinking was that if a teenager had had sex, they’d already likely been exposed to a virus strain.
However, several studies have since shown that you can contract the virus even if you are not sexually active.
There are two ways this can occur. The first is through other forms of genital contact such as hand-to-genital or mouth to gential.
The second way is that, because HPV is transmitted through skin-to-skin contact, it can be picked up from touching an unsanitized surface such as a a table at a doctor’s office or at a gym.
Last year, new guidelines from the Advisory Committee on Immunization Practices declared the vaccine would be administered in two doses over six months instead of three doses.
The new rules came after years of campaigns from cancer experts insisting an easier schedule would encourage more people to protect themselves from the sexually-transmitted infection.
Despite strong evidence of safety and effectiveness, vaccination rates in the US remains very low compared to other countries, including Spain, Portugal, Greece, Australia and New Zealand.
According to the most recent data from the CDC, about 50 percent of girls between ages 13 and 17 and 37.5 percent of boys in the same age range were up-to-date on the HPV immunization schedule in 2016.
Previously, it was believed HPV was most strongly linked with cervical cancer in women. Research since has shown links with penile, anal, mouth, throat and other cancers in men.
According to the CDC, each year about 19,000 cancers caused by HPV occur in women in the US, with cervical cancer being the most common.
And about 8,000 cancers caused by HPV occur each year in men in the US and oropharyngeal (throat) cancers are the most common.