HPV Vaccination - Facts, Side Effects and Risks

HPV or Human Papillomavirus is the most common STD (sexually transmitted disease) in the United States, so much so that around 75% of men and women will be infected with the virus at some time in their lives. HPV is contagious, with the strains that cause genital warts and cancer being very contagious. HPV is easily transmitted during sexual activity and infected people may not even be aware that they have the virus. This is because some strains produce no symptoms and not everyone exposed to other strains will have any symptoms. The strains that lead to cervical cancer in women and genital warts are in the high-risk category.

In an attempt to prevent the incidence of cervical cancer, research was started in the 1980s to find a suitable HPV vaccine for the strains of the virus that are precursors to cancer. This work was being carried out by 4 different research teams simultaneously – at the University of Queensland in Australia, the University of Rochester, Georgetown University and the US National Cancer Institute. The first HPV vaccine was produced by Merck and Company, under the brand name Gardasil. By mid 2007, Gardasil had been approved for use in 60 countries, while a second HPV vaccine by GlaxoSmithKline had been approved, called Cervarix, though it wasn't approved for U.S. use until 2009.

Both brands of HPV vaccination protect women against HPV-16 and -18 which are the strains that cause about 70% of cervical cancers and are implicated in other types of genital cancers as well. Gardasil also offers protection against HPV-6 and-11 which are responsible for genital warts, as well as the several strains that appear to be precursors for anal, penile, vaginal, vulvar and oral cancer caused by HPV.

Western countries, including Australia, Europe, Canada and the United States recommend HPV vaccination for girls and young women in an effort to prevent cervical cancer. Some of these countries have made the vaccine available at no charge to girls in the optimum age group, with Australia having a school-based immunization program for girls in their first year of high school (about 12 years of age). The US has approved the use of Gardasil for young men and boys because it has been shown to be effective in preventing genital warts.

HPV vaccination requires three injections, two months apart, over a six month period. Gardasil has been approved for girls and women aged from 9 to 45 years and for boys from 9 to 15 years. Cervarix has been approved for women and girls aged between 10 and 45 years. Both vaccines have the best chance of successfully preventing cancer if they are given before any exposure to HPV, which means before sexual activity begins. The recommended age for girls to receive the vaccine is between 9 and 12. Women who have already been sexually active could still benefit from HPV vaccination provided they have not already been infected with the HPV strains that the vaccines cover.

Possible side effects of the HPV vaccine

The HPV vaccine doesn't contain any live virus and so it isn't able to give you HPV.

Most vaccines have some side effects in some people; however, the diseases they aim to prevent are way more dangerous than these possible vaccination side effects. Most side effects of the HPV vaccine are a reaction at the site of the injection and include redness, soreness or swelling, although some cases of headache or nausea have been reported. These side effects usually disappear in a few days or less and only affect a small percentage of those receiving the vaccine. Worldwide, the reported number of cases of side effects is quite low compared to the number of vaccine doses that have been distributed.

In September 2009, in the U.S. alone, this number is more than 26 million doses; there have been 15,000 VAERS (Vaccine Adverse Event Reporting System) reports that have followed vaccination. 93% of these reports involved the non-serious side effect listed above, while the remaining 7% fell into the serious category, involving life-threatening, hospitalization or death though none of these were proven to be linked to the HPV vaccine.

As new clinical evidence is accumulated, product information on the HPV vaccine is updated but to date, there have been no regulatory agencies that have needed to take any corrective action.

Potential risks

The main risk of the HPV vaccine is that women will become complacent because they believe they are immune to all strains of HPV. There are well over 100 HPV strains and the vaccines only cover a few of these - the ones that have been linked to cancer. Vaccinated men and women can still be infected with HPV strains that are not covered by the vaccine.

If older men and women receive the HPV vaccine, there is a risk that they have already been infected with the strains of the virus that the vaccination covers. If this is the case, they risk developing precancerous cell abnormalities, even though they have been vaccinated. HPV testing is advised for all women over the age of 30, even if they have received the vaccination.

HPV vaccination is not recommended for pregnant women. The effect on fertility of the vaccine in the long-term is not yet known although no adverse effects are expected.

As the HPV vaccine is relatively new, there is no data to support its effectiveness in preventing cervical and other cancers in the long-term. There is still insufficient education around the issue of HPV vaccine and, because of this, many girls are not receiving it because of cost, inconvenience or moral issues.