HPV Vaccinations – By the Numbers

I was out a few nights ago and a friend asked me my thoughts on vaccinating her daughters for HPV – Human Papillomavirus. We’ve all seen the ads but what is it? Why is it taking center stage now? And in the grand scheme of sexually transmitted infections (STI) how dangerous is it?  

I didn’t have an opinion – although my gut was telling something so I thought I’d take a look. I’m writing this as I’m doing my research… so I’m taking you on my “thought” journey to look at the data and see what I think. This is how I’m thinking about the numbers – but if you find a different way let me know.

HPV is actually better known as the virus that causes warts – yep those icky things on your hand and feet. There are around 100 HPV strains that have been categorized.

There are about 40 known strains of HPV that infect the genital region. Of these 9 of these are considered high-risk – causing anything from low-grade cervical changes to cancers in women. Low-risk strains (the American Cancer Society lists 2) may cause genital warts, respiratory pappillomas (very rare – and involves the transmission from a mother to a new born) or low-grade changes in the cervix.

So… what about the other 29 strains?

The Centers for Disease Control state that 50% of sexually active adults (men and women) will get HPV at some point in their life.

According to the American Cancer Society “70% of HPV infections appear to go away within a year and 90% within 2 years.” The CDC adds that “in 90% of the cases, the body’s immune system clears the HPV infection naturally.” Most people don’t even know that they’ve had it.

So for a huge number of the infected there is no cause for alarm – our body takes care of itself and off we go.

Forgive me while I do a little math… let’s start with 200 people, 100 men and 100 women. Okay out of each group 50 will get some strain of HPV – whether it is a high-risk or a low-risk strain 90% of them will clear it up in two years. That leaves 1 woman and 1 man left to worry about right (I know – it could be 2 women or 2 men – but this is a thought experiment)?

So what about that 10% – which is a huge number if you’re looking at the total population of the US – what happens to them? Remember they can have either high-risk or low-risk HPV infections.

Now I’m going to limit this to cancer – the other types of problems HPV creates can be dealt with fairly easily – but cancer kills.

To figure out the risk to our 10% I plugged in the American Cancer Society’s estimates of the number of HPV related cancers in 2008 and the US population curtsey of the US Census Bureau and got the table below.

So… this gets a little funky – I made the US Population numbers to equal 10% of the population. So the risk to the 10% is the percent below. Not the risk to the general population.

HPV Related Cancer  Est. Number of cases US Population Est. (2008) the 10% problematic HPV Percent of the problemenat HPV population at risk for Cancer
Cevical                11,070                30,382,464.00 0.03643549%
Vulvar                  3,460                30,382,464.00 0.01138815%
Vaginal etc                  2,210                30,382,464.00 0.00727393%
Penile etc                  1,250                30,382,464.00 0.00411422%
Anal Men                  3,050                30,382,464.00 0.01003869%
Anal Women                  2,020                30,382,464.00 0.00664857%
       
RRP                  2,000                      450,514.29* 0.44393709%
       
Total                25,060                30,382,464.00 0.08248179%

  *estimation of US births in 2008

Our two people – have less than a .08% chance of getting a HPV related cancer to their problematic HPV strain – less if you are male and a little more if you are female. And there isn’t a vaccine for men – so if you are looking at the 30 million remember that the vaccine could only help 15 million of them.

Which means that the Jill on the street has a .008% chance of getting a HPV related cancer and yes genital warts can be an embarrassment but they aren’t cancer. I think most lottery odds are better. On the site Dr. Math it is reported that a person has a 1:80,089,128 chance in matching all 5 numbers plus the power ball if playing Powerball Lotto. I didn’t look at his formula but thought we’d roll with it – it makes my point.

Now let’s play another game because even 15 million problematic HPV infections in women seems a like a lot. But remember there are 40 strains of HPV that infect the genital region – of which 9 are high-risk.  

Gardasil, one of the two vaccinations for HPV on the market, was designed to prevent the following:

  • 2 types of high-risk HPV known to cause cervical cancer that are responsible for 70% of all HPV related cervical cancers.
  • 2 types of low-risk HPV known to cause genital warts that are responsible for 90% of all genital warts.

Cevarix will protect against the same high-risk HPV but not the low-risk.

So, if our young woman gets cancer from HPV – she has a 41% chance of having a cancer that isn’t cervical. She also has a 30% chance, if she has cervical cancer, that it isn’t one of the two strains included in the vaccinations.

These odds become more astronomical by the minute….     

The American Cancer Society in their guidelines state:  

  • girls ages 11 to 12
    The vaccine should be given to girls ages 11 to 12 and as early as age 9.
  • girls ages 13 to 18
    Girls ages 13 to 18 who have not yet started the vaccine series or who have started but have not completed the series should be vaccinated.
  • young women ages 19 to 26
    Some authorities recommend vaccination of women ages 19 to 26, but the American Cancer Society experts believed that there was not enough evidence of benefit to recommend vaccinating all women in this age group. We do recommend that women ages 19 to 26 talk to their doctors or nurses about whether to get the vaccine based on their risk of previous HPV exposure and potential benefit from the vaccine.

I’m not against vaccinations – I think they are great! In fact just got a booster shot at the doctor the other day for tetanus. No Small Pox almost no Polio – these were great things that saved lives and dealt with viruses that were killing us. But we are being asked to “protect our girls” from an almost nonexistent cancer. A cancer that appears in a sliver of the population and the biggest risk is from cervical cancer which currently has a survival rate of 92% with early detection and 71% for detection at all stages.

Yes – HPV is very infectious but statistically it’s not killer.

So why? Why the huge ad campaign? Why make us feel that something is terribly wrong when the number don’t really support it?

Viruses evolve with their hosts – that said HPV has been around for a very long time – infecting us for millions of years.

The odds are that it will continue to be an occasional problem and general nuisance. A lot of viruses are in a push-me-pull-you state with their hosts. They come. They go. And Leave immunity in their wake.

Which makes me wonder if there is any indication of reinfection with HPV? You know like the common cold – you get it and then get it again and we never seem to get much better at fighting it. But the raw data – just the numbers that we’ve looked at suggest that infection happens – is cleared – and then you have your own immunity. 

Is it the right thing to do? Why are so many women talking about this and wondering what they should do? Well… remember the ads?

Let’s look at the issue another way.  

If we become convinced, as a society, that the guidelines should be adhered to there are an estimated 4.5 million children born every year in the US. Imagine half of them are girls…2.25 million. That means that if we go by the America Cancer Society guidelines and vaccinate every young woman, right now, between the ages of 11 and 18 that is an estimated18 million young women.

Gardasil goes for $120 a dose and three doses are required for immunity so that is $360 per woman.

18 million young women multiplied by $360 per treatment is $6.5 billion…with an additional $900 million possible every year thereafter.

If they succeed in making us believe… what? That we are doing a disservice to our young women not to vaccinate them – this may be a “nice to have” but I just can’t classify it as a “need to have”.  

Oh, and on the American Cancer Society website they have a section that interests me in their FAQs. “Did the American Cancer Society play a role in the development of the HPV vaccines?”

The answer… Yes. One of the four teams received funding from the ACS in the mid 1990s – the grant could be anything from a little to a lot…  

And you wonder why you’ve seen all the ads. I don’t. This is economics driving healthcare – and I have to admit I’m rather sad about it.

But there is a flip side… I was talking to another friend who has decided to immunize her daughter. She did it because she and another mother she knows had been one of the 10% – the ones with some sort of problem with their vaginal wall cells caused by HPV. The treatment was painful and my friend felt that since her insurance was paying for it she would rather not take the risk of there being a genetic predisposition.

Another woman said that she would have done it – her daughters are older now – just because it was one less thing to worry about.

Yet another said that since there are very few “wins” when preventing cancers of any kind that it was just nice to know you were doing something.

So where are we?

A drug company is going to make billions off our sense of responsibility? This will be a choice each of us will have to make. The risks are low yet it seems this is a bizarrely difficult decision to make.

What about you?  

 ~ Tess

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