It’s August, and that means it’s National Immunization Awareness Month (NIAM).
Vaccines are a highly effective way to provide immunity before people are exposed to potentially life-threatening diseases. Young children are at the highest risk of getting sick, so giving vaccines to them directly offers the best protection. Diseases that were common in the past, like smallpox, measles, and polio, can be completely prevented by vaccines and for that reason, we don’t see those diseases nearly as often today. As a result, there are fewer doctor’s visits, hospitalizations, and early deaths.
Vaccines don’t just keep the individual who receives them healthy; entire communities are protected. Once enough people are vaccinated, the chance of an illness or disease outbreak becomes very low. So low, in fact, that those who are not able to be vaccinated (infants, pregnant women, elderly, and those with weakened immune systems such as children or teens with cancer, sickle cell disease, or chronic inflammatory diseases) will benefit. When a large portion of a population is vaccinated, this situation is referred to as “herd immunity” and has helped wipe out many diseases.
However, if too many people opt out of receiving vaccines, herd immunity no longer protects the community and there is an increased risk of disease outbreak. Vaccines have worked so well for so long that people have forgotten how serious some of these diseases can be. But many vaccine-preventable diseases that are not common in the United States still make people sick in other countries. It’s possible for travelers to bring these diseases when they visit the U.S., which is why it is important to continue the vaccination process2.
How do vaccines work?
When a person gets infected with a specific antigen (any substance that stimulates the immune system to defend against germs), the body’s immune system responds to fight that antigen. The immune system, which is made up of special cells, proteins, and tissues, attacks and destroys the invading substance. This process takes time, and oftentimes the immune system can’t work fast enough to prevent the person from getting sick. The good news is that the immune system has an excellent memory. If it encounters the antigen again, the body responds quickly enough to prevent the illness a second time.
A vaccine works by training the immune system to recognize certain diseases by imitating an infection. This exposure almost never results in an infection, but can cause minor symptoms, such as a fever. The vaccine, often made up of dead viruses or weakened live viruses, activates the immune system’s memory and allows the body to react quickly and efficiently to future exposures. Vaccines are tested to confirm they are safe to receive and successful at preventing serious illnesses1.
Why have vaccines been questioned as a cause of autism?
In 1998, Andrew Wakefield, a British doctor, published a paper in the Lancet describing his research that considered a connection between the measle, mumps, and rubella (MMR) vaccine and autism spectrum disorder (ASD). The paper was found to have significant flaws and in 2010, it was retracted (should be considered invalid as a source of knowledge) by the Lancet3,4. However, before the retraction, the news of the association was widespread, causing people to question the safety of the MMR vaccine. Since Wakefield’s study, multiple research studies have shown there is no link between the MMR vaccine and ASD5,6,7.
One explanation for the apparent connection between the MMR vaccine and autism is that the age when MMR is first given (approximately 12-15 months) overlaps with the timeframe when the signs of ASD typically emerge8. While many parents reason there must be a connection between the vaccine and the diagnosis of ASD, there is no scientific data that proves this to be true.
The underlying cause of ASD is generally unknown; however, it is suspected to be a multifactorial condition, meaning there are many genetic and environmental factors that all play a role in the development of symptoms in a person (see the “jar analogy” regarding multifactorial inheritance). The more we learn about ASD, the evidence tells us that it is highly genetic, but that there are multiple genes (as opposed to just one gene) that contribute to this disorder. Currently, it is unclear what outside or environmental factors influence the symptoms of ASD (and how those factors interact with each other). While we cannot say whether vaccines play a role in ASD in children who have a genetic susceptibility, the data suggests that vaccines alone are not enough to cause ASD.
Scientists and researchers have designed several approaches to accomplish safe vaccinations; these vaccines have been in use long enough for us to know they work and that they save lives.
The risk of an adverse reaction following vaccination of any kind is very low9; it has been disproven that the MMR vaccine is a cause autism spectrum disorder by itself
If you have concerns about vaccinations, please talk with a licensed healthcare provider who can consider your child’s medical history when discussing vaccine recommendations.
Centers for Disease Control and Prevention (https://www.cdc.gov/vaccines/index.html)