Vaccines reduce disease

200910191117.jpgby otisarchives4

How safe is Gardasil? And a new antivax FAQ

[Via Bad Astronomy ]

Fighter for truth and science Ben Goldacre tweeted a link to a nifty blog post showing just how safe the Gardasil HPV vaccine is. Using easy-to-understand graphics, the post (on the very nice Information is Beautiful blog) makes it very clear that comparing the good it does to the very tiny risk, Gardasil is a monumental achievement. Actually, just all on its own it’s a big advancement in the fight against cancer. The post also puts it in place among other low-risk dangers like getting hit by lightning or being killed in an earthquake. I like that; I myself have compared it with dying from falling off a chair.

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I am so glad to see this. I had seen the graphic all around the web but it had lost its link to the original. It helps place the risk in much better perspective. The risk-reward equations for vaccines is just not well understood by many people.

I have had people tell me that vaccines really do nothing, that polio and smallpox were not eradicated by vaccines but by better hygiene. Awfully coincidental. Let’s look at some data.


polio rates

This is from the CDC and shows the rates of paralytic poliomyelitis in the US (PDF). According to the CDC, the rates of polio had actually increased from the 1800 because of increased sanitation. IN those earlier times, children were probably exposed on a regular basis, even while in the womb, and developed immunity without the resulting paralysis. Polio is especially deadly the older the patient is.

As they state:

In the immediate prevaccine era, improved sanitation allowed less frequent exposure and increased the age of primary infection. Boosting of immunity from natural exposure became more infrequent and the number of susceptible persons accumulated, ultimately resulting in the occurrence of epidemics, with 13,000 to 20,000 para- lytic cases reported annually.

So, 20,000 cases down to 61 in 10 years. All after the vaccine was introduced. Let’s look at another disease. Measles:


measles

or Rubella:


rubella

or mumps (vaccine licensed in 1967)



200910191047.jpg

Just a coincidence that the numbers of people infected with these diseases dropped dramatically after the vaccine was licensed? I don’t think so.
We eradicated smallpox due to the use of a vaccine and are well on the way to eradicating the polio virus. The only time many of these diseases appear in the US is when a high enough percentage of people fail to get vaccinated. This causes herd immunity to fail, allowing the disease to spread to many susceptible people.
While the Amish do vaccinate themselves (there appears to be no religious reasons prohibiting vaccines. Surveys indicate that their main concern is ‘fear of side effects.’), the rates have often been lower than needed for herd immunity, resulting in outbreaks of serious diseases, such as pertussis, in their communities.
When people fail to get immunized, they not only put themselves at risk, they put others at risk also.
The disease can not spread unless there are enough people around who are able to spread it. For a lot of these illnesses, less than 85% immunized means that the disease can cause a lot of damage.
Vaccination has a strong community rationale. One that is some cases can be more important than a personal belief. It depends on just how dangerous a particular epidemic is to the community.
And vaccinations do reduce the spread of epidemics.

2 thoughts on “Vaccines reduce disease

  1. Sadly, all the graphs you show will be lost on those who believe that hygiene solved the problem. Too often we try to explain to those who are dogmatic in their belief systems why their logic is flawed, but unfortunately, no amount of evidence will convince those whose decisions are not based on facts, but based on their internal belief systems.

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