Vaccines vaccines vaccines!

To simplify things, vaccinations work by injecting individuals with the disease it aims to prevent. To understand why this works you first need to get an idea of how the human immune system works. The main goal of our body’s immune system is to prevent and mitigate infection. On a daily basis, the immune system intercepts viruses and bacteria, or antigens, that pose a threat to our health. When immune cells detect these foreign particles, the immune system creates antibodies and white blood cells that go to work fighting the antigens. In addition to dealing with pathogens in the short-term, the immune system also prepares for the long-term as memory cells “remember” the specific antigens the body is fighting. If the body ever encounters the same type of disease in the future, these memory cells activate the immune response immediately, allowing the body to kill off the pathogens before they cause any harm.

Vaccinations take advantage of how the immune system operates by presenting the body with a version of the virus or bacteria that activates an immune response without posing a real threat. Different types of vaccines achieve this in different ways. Live vaccines contain a living version of the pathogen that has been weakened while inactivated vaccines contain inactivated pathogens that still produce an immune response. Another method is the subunit vaccine, that only contains parts of the virus or bacteria. Toxoid vaccines consist of weakened toxins that teach the body how to fight off the real thing. Finally, conjugate vaccines are targeted toward bacteria that are disguised under a sugar-like coating called a polysaccharide. The vaccine connects polysaccharides to antigens the body is aware of to help build recognition for the disguised bacteria.

While vaccines do not contain pathogens that present a real threat to patients, there are potential side effects. For instance, 17% of young people who receive the inactivated influenza vaccine develop a fever. For the measles vaccine, around 12% of recipients experience a minor reaction such as a fever or rash. Another concern anti-vaxxers cite is that vaccines can cause autism. However, the scientific consensus on this issue holds that there is no connection between vaccines and autism. In fact, almost all of the authors that originally proposed a link between the MMR vaccine and autism retracted their initial interpretation. Not only was the data insufficient for such a connection, but there was also a financial conflict of interest: one of the authors received a large sum of money to investigate a claim against the vaccine manufacturers.

Part of the reason vaccines are so safe is because of the thorough testing process they must go through before being released to the public. This process consists of six stages: exploratory, pre-clinical, clinical development, regulatory review and approval, manufacturing, and quality control. Clinical development is one of the longer stages, consisting of three phases that are given to slowly scaled test groups. The entire process can last for over a decade; in the case of the COVID-19 vaccine, nearly the entire world focused its time and resources on development to shorten that length to under a year.

Vaccination side effects are very real, but they pale in comparison to the consequences of the diseases they prevent. For instance, based on measles data from 1985-1992, almost a third of measles cases experience complications. 8% of the cases developed mild reactions such as diarrhea, 6% developed pneumonia, and in total, 0.2% of the measles cases resulted in death. Today, measles is still a very deadly disease, killing over 140,000 people worldwide in 2018 alone. In contrast, the only documented deaths caused by the measles, mumps, and rubella (MMR) vaccine come from a very problematic study from 1998. The study found that 8 of 49 children receiving the MMR vaccine died within 15 days of receiving the vaccine; however, no proof that these deaths were related to the vaccine is provided. It is also unclear whether these children had health conditions that made them susceptible to side effects.

Vaccine side effects do exist and some healthy skepticism is justified when determining whether to have a pathogen injected into you. However, the statistics make it obvious that the main side effect of vaccines is staying alive.