HPV Vaccine in the News. Again.
Over the past couple of weeks, the internet has been abuzz about the HPV vaccine. A story published by the Toronto Star claimed to investigate the “dark side” of the HPV vaccine with individual accounts of symptoms that people had after receiving the vaccine, but did not discuss the larger studies that had been conducted that debunked these claims. After the Star received a slew of responses (like this one) that pointed out the poor scientific reporting, the article was taken down from the site and an article pointing out these faulty methods was posted.
The HPV vaccine protects against human papillomavirus, which is associated with cancer of the cervix, vagina and vulva, anus, throat, and mouth. It is a three-dose series given over a 6-month period starting at age 11-12 (though it can safely be given as early as 9) and is recommended for all kids. Both available forms of the vaccine protect against HPV16 and 18, which are associated with at least 70 percent of HPV-associated cancers, and one of the marketed brand includes protection against HPV6 and 10 as well, which cause genital warts.
Protection against both cancer and genital warts? All good, right? But this isn’t the first time that the HPV vaccine has been in the news, which makes some people worry.
But the primary reason that the HPV vaccine pops up in the news is because of the same mistake made by the Star: stories that focus on reports made by individuals that either rush to conclusions or fail to acknowledge the incredible amount of information that we have pointing to the fact that the vaccine is safe.
For example, in this devastating story of a young woman that passed away the same day that she received an HPV vaccine, the press picked up the story and made the association with the vaccine before the actual cause of death was determined by the coroner. It turns out that her death was from overdose by diphenhydramine, the generic form of Benadryl, and there was no reason to believe that the HPV vaccine had played a role. Very often, this mistake is made by the press: something bad happens, and because the HPV vaccine was given hours, days, or weeks beforehand, it is blamed for that effect.
I’m not trying to say that these reports and stories aren’t important: they are. These individual experiences are what are reported in the Vaccine Adverse Event Reporting System, which tracks the reports and looks for patterns. If there are enough cases of the same side effect, the Center for Disease Control and the Food and Drug Administration will look into whether the vaccine actually causes this side effect. They do this by setting up studies that examine large numbers of people (often thousands) that have received the vaccine or by analyzing data to see if the events seen are more likely to happen after the vaccine compared to occurring without vaccine exposure.
The study step of this process is incredibly important, because it’s the only way to tell if it is the vaccine that actually causes the side effect that is reported.
Now wait, you might be saying. If there are enough people that report a side effect, doesn’t that mean that the vaccine caused it? It’s an important question. Here’s why the answer to that question is no:
The HPV vaccine is given at a particular age to make sure that it works as effectively as possible. Giving the vaccine at 11 or 12 gives kids protection before most kids have been exposed to the virus AND has been shown to lead to the best immune response by the body (better than if it is given at older ages). But there are other things going on with preteens and teens that have nothing to do with the HPV vaccine.
Puberty, for example, can be associated with all sorts of changes that might occur after age 11 or 12. It wouldn’t make sense to blame the HPV vaccine for acne, however, when we know that acne would occur in a lot of teenagers anyway. There are other things that are known to show up more frequently during the teen years, like some autoimmune diseases, that some people have blamed on the HPV vaccine. When researchers follow-up on these claims – in this study, for example, that studied over 900,000 females that received the vaccine in Sweden in Denmark – they have found that there is no good evidence that autoimmune diseases occur more frequently after the HPV vaccine.
This is not to say that the HPV vaccine does not have side effects. All vaccines and medications have some side effects, and it’s important to know what they are. The HPV vaccine has been associated with side effects that are self-limited and resolve on their own, including soreness of the arm, headache, mild to moderate fever, and fainting. As with almost all vaccines and medicines, there is a risk of having a severe allergic reaction, though studies have shown this risk to be low for the HPV vaccine (about 1.7 cases per one million doses of HPV given in one large study looking at adverse events from the HPV vaccine. For reference, the risk of being struck by lightning in the U.S. is about 1 in one million).
You might ask why someone would make such a big fuss over these details, but here’s my reason: the HPV vaccine works. Since the HPV vaccine was recommended in 2006, rates of HPV infections in women in the U.S. have already dropped. In Australia, where they have higher rates of HPV vaccination, they have already seen a decrease in the number of precancers of the cervix, which are detected by Pap smears. Australia has also seen a reduction in rates of genital warts for both men and women.
Less cancer? I’m all for it. Fewer cases of genital warts? Bonus. And all of the best research points to the HPV vaccine being a safe way to make that happen.