Vaccines... How Do They Work?

Vaccines... How Do They Work?

It’s becoming a frighteningly common trend to not vaccinate children against highly infectious, and often deadly, diseases. There are a lot of misconceptions about what vaccines are and what they do. So, what are they? How do they work?

There are several types of vaccines, and scientists are always working on creating newer and more effective ones. As of writing this article, here are the most commonly used types of vaccines:  

  • Live- Attenuated Vaccines- This vaccine is made with a live and weakened version of the bacteria or virus you are being inoculated against. Since it causes such a similar reaction in your body as the real thing, it creates a more thorough immune response. With these, you’re likely to be safe for life! Think of measles, smallpox, and chickenpox.  
  • Inactivated Vaccines- This one uses a dead version of the source of a disease or sickness. These vaccines are weaker and require more shots over time to keep up immunity. Think of the flu and rabies vaccines.  
  • Toxoid Vaccines- This vaccine is made using a toxin made by the virus or bacteria the shot is for. So, your immune system attacks the toxin and not the virus or bacteria itself. These require booster shots to keep the immune system up to the task of fighting. Think of the tetanus vaccine.
  • Subunit, Recombinant, and Conjugate Vaccines- These vaccines are made to focus on a specific part of the virus or bacteria they’re meant to protect against. So, when your immune system recognizes that part— the proteins, sugars, or casings of a virus or bacteria— your body reacts. These provide a strong immunity, but sometimes require boosters. Think shingles, whooping cough, and meningitis.

Knowing the different types of vaccines is all well and good, but how do they work? How do they protect you against these viruses and bacteria? Let’s focus on the meningitis vaccine, for example.

Getting a vaccine is like making a practice 9-1-1 call for your body. As mentioned above, the meningitis vaccine falls into the Subunit, Recombinant, Conjugate Vaccine category. Scientists take a part of the bacteria that causes meningitis, or an illness very similar to it, and use it as the basis of the vaccine. When it is introduced to the body via vaccine, the meningococcal bacteria encounter the body’s own police force: lymphocytes.

There are two major types of lymphocytes, T-cells and B-cells. Helper T-cells are like the dispatch officers of your body. They activate the body’s immune response by secreting a chemical signal to alert the immune system to the invader and directs the police, B-cells, to the location of the infected cells. B-cells hurry to the location given to them by the Helper T-cells, and once there they search for the disease present in the body. The B-cells use something called the “antibody response” to take down the bacteria. They secrete these molecules called antibodies that are designed specifically to attack the disease’s antigens. The B-cells have to determine which antigens fit perfectly with their antibodies for their attack to be the most successful. Once compatible shapes are found that fit with the meningococcal bacteria, they stick together, trapping the antigens.

B-cells can usually take care of these infections on their own, but if they can’t the Helper T-Cells have to call in the big guns: Killer T-cells. The Killer T-cells are like the body’s own SWAT team. They come in and take on the more dangerous missions. Once on the scene, Killer T-cells latch onto infected cells release a biochemical that breaks down and destroys the invading infection.

After the threat is gone, these cells convert into memory cells. These guys are what really make vaccines work. They’ve seen it all, grizzled veterans of facing the meningococcal bacteria, so they know just what to do to take it down. They teach all the other B-cells and T-cells what they know, so if the body is ever exposed to those antigens again, they know just what to do to get rid of them and protect against infection. Usually, the immune system only has to go through one or two runs of this practice before they are completely set to protect the body. Sometimes, though, they require ongoing training. You see this in the vaccines that are required to get yearly or every few years, like the flu shot. The body’s memory of the antigens either weakens or the antigens evolve to not perfectly fit the body’s profile, so they can’t engage against the invader as well as before. Keeping up with boosters and getting these shots regularly, though, can keep your own little police force performing at its best, keeping you— and those around you— free of sickness.