Something big is currently going on the disease world! Chances are unless you’ve heard about this is some way, shape or form, unless you have been living under a rock (No judgment here, I went dark for a few weeks. SO MUCH SCHOOLWORK.). Currently there is an ongoing national outbreak of the measles virus linked to Disneyland in California. This is big news for several reasons; the number of cases is continuing to rise, measles was eliminated from the U.S. in 2000 and it’s adding fuel to the fire of the on going anti-vaccination debate. Having a background in public health, epidemiology and virology, this topic and these kinds of events hit close to home for me. Many of my facebook friends and twitter followers are VERY clear on where I stand on the subject and can be subject to a rant on this at any given point of the week. Because of this I thought it was important to write a post explaining why I feel the way I do about vaccinations and also provide some translation from scientific worlds of immunology and infectious disease so that maybe others can understand and help those who may be on the fence about it.

Let’s start with anti-vaccination campaign and the arguments people are using to support this position.  One of the main reasons people are unsure or against vaccinations for children is the question of whether they have been linked to horrible side effects like Autism or Guillian Barre syndrome . Another popular argument that has gained traction is that we should not be injecting harmful chemicals into our children’s bodies. I’m going to stop with these two argument because I think this would be a good point to go over some basic vaccination science.

The purpose of a vaccination is to expose your body to a micro-organism or toxin prior to infection. By giving your body a chance to build up immunity in a non-pathogenic situation (does not cause disease), when your body comes into contact with a pathogenic version  of the micro-organism you wont get sick or you wont get as sick.

A vaccination typically consists of an antigen; the molecule you want your body to form an immune reaction against,  and an adjuvant; something to enhance the immune reaction. Antigens can be a whole micro-organisms, like a killed bacterium/virus, or just part of one, like a viral protein or a bacterial cell wall.  Some vaccines may be live attenuated vaccines (Virus is alive, but not strong enough to cause disease). Adjuvants are used to enhanced the reaction your body will have to the antigen. In some cases (NOT ALL), an adjuvant could be a chemical compound like aluminum hydroxide or thimerosol (EthylMercury). (For the sake of this particular post, we will focus on that.  If you have any left over questions feel free to drop them in the comment box and I will do my best to either answer or point you in the right direction of the information.)

Some of you might now be thinking, “Hold on, their injecting us with aluminum?!” but this is the chemical found in antacids that help to reduce the acidity of your stomach acid and isn’t used in large quantities. Additionally, it works as a stabilizer to keep the antigens from sticking to the container during storage. Thimersol IS NOT mercury (methyl mercury), a compound found naturally in the environment that bioaccumulates in the body, but does contain mercury within the compound. Methyl mercury is what is used in those old thermometers and what you hear about when they warn against eating certain fish. The difference between thimersol and mercury is the way it metabolized (broken down) by the body. Thimersol is metabolized by the body much faster than methyl mercury and is cleared out of the body.  Further more, even though no correlation between thimersol and autism has been found, thimersol is no longer used in any vaccines recommended for children, with the exception of the multi-dose flu vaccines. If you do not want the flu vaccine that contains thimerosol, just ask your doctor for a single dose vial; those are thimersol free.

Micro-organisms that are used for the vaccines are grown in different forms of media. Some viruses are grown in eggs because they need living cells in order to reproduce. Egg fluid containing viruses are cleaned many times in order to remove the actual egg proteins but still may contain small traces. This is why it is recommended that if you have an egg allergy you avoid vaccine like the flu vaccine. Its not the virus you would be having a reaction to but the egg protein. All vaccines go through a series of rigorous tests called clinical trials, to ensure the safety and effectiveness before they are mass produced and administered to millions of people.

When enough people in a population are vaccinated for a disease, the population as a whole benefits from something called herd immunity. Herd immunity occurs when there are not enough susceptible people in the population for the microorganism to continue spreading (.  Because there are not enough people to get sick and pass on the virus, people who are not vaccinated are protected from infection within that population. This protection is a result of the virus not being able to come in contact with a susceptible individual before it dies out. The amount of a population that needs to be vaccinated in order for herd immunity to take affect varies for each disease. For measles, its 95%. Herd immunity is especially beneficial for those with autoimmune diseases or other compromised health issues who may not be able to get vaccinated.  This would include cancer patients and other immunocompromised, young infants and the elderly.

Now that you understand the basic science behind vaccinations, lets talk about why vaccinations are awesome. Thanks to vaccination some disease have been eradicated (smallpox, rinderpest), while other diseases are considered well controlled or eliminated in different areas all of the world. In the U.S. these disease would include measles, mumps, rubella (MMR), polio, diphtheria, pertussis, tetanus and chicken pox. All of those disease used to cause high rates of child mortality. So these vaccines are considered a HUGE success for public health.

In recent years, people are starting to decline or delay vaccinating their children because a paper published by Dr. Andrew Wakefield in 1998 that stated 12 children who were vaccinated with the MMR (Measles, mumps and Rubella) vaccine developed autism shortly after vaccination. Since then, this paper has been RETRACTED and Dr. Wakefield was discovered to have had financial interest in a series of vaccines that gave the MMR viruses separately instead of all together. In fact, Dr. Wakefield was stripped of his license to practice medicine as a result. It has since been acknowledged that while MMR is administered to children at the same age that autism symptoms begin to appear, it is NOT the cause.

As more people decline to have their children vaccinated, the smaller the coverage rate gets. Once the coverage rate drops the population of non vaccinated individuals becomes more susceptible to infection due to lack of herd immunity. At this point, it could take one person from another population (over seas, different part of the country) who is infected with a disease to then spread it to the susceptible population. This is what is thought to be the case with the Disneyland outbreak in addition to other smaller outbreaks. Now there are people being exposed all over the country and stories like this one and this one are popping up all over the country.

I write all of this to explain that those of us who are healthy and those that are in charge of healthy children has a responsibility to protect those who do not have the ability to get vaccinated. We have eliminated or eradicated disease that cause a lot of pain and suffering in the past and it would be a tragedy to loos the progress that has been made in the disease world. Additionally, as someone who works with infectious diseases, I know and read about and witness the discovery of new pathogens every day. It would be great if scientists, epidemiologists and doctors could focus on emerging health threats as opposed to those that we have effective tools to treat because of unfounded theories. I am looking at this situation not only as a scientist but as a future parent and future elderly person. Please vaccinate yourself and your children. #IAmTheHerd and you should be too.