The concept of vaccines seems simple, as is the making of them, but what really takes time is assuring that they are safe for people. Whenever a new virus pops up, scientists scramble to develop a vaccine. Sometimes, depending on the type of virus and how it behaves, vaccines can cause more damage than the disease itself.
What Are Vaccines
When you get sick, your body naturally produces antibodies that tag and neutralize the invading virus or bacteria. The next time you’re infected with the same pathogen, your immune system is prepared and is able to quickly produce antibodies. This is called immunological memory. A vaccine simply takes pieces of the virus or bacteria and creates an immune response without the nastiness of getting sick.
Vaccines Keep You From Dying
The first vaccine was discovered when Edward Jenner infected a young boy with cowpox. This protected the boy from smallpox. Did the boy develop a giant pustule from cowpox that led to scarring? Yes. Did the boy die from smallpox after exposure? No. The point of vaccines is to keep people from dying of a deadly disease. Sometimes, the vaccine itself can make you sick, but the point is that you’re not sick enough to the point where you die.
Lots of Testing
Before injecting someone with viral particles, vaccines are tested in Petri dishes, then mice, then monkeys, and then humans. First scientists look at the way isolated immune cells react to the vaccine. Then, they look at how live animals, like mice, react. Monkeys are next because they most resemble people. Only when a vaccine is safe in our closest animal relatives do we give it to people. A SARS-CoV-2 vaccine has been given to a small group of people, but it will be months before it is proven to be safe for commercial production. Because everyone has a different immune system and we all react differently to vaccines, thorough testing is necessary to make sure that the vaccine doesn’t kill people.
Sometimes, your own body is your worst enemy. This is true for autoimmune diseases, cancers, and antibody-dependent enhancement or ADE, which occurs after the body creates antibodies against a certain virus. When the virus acquires a slight mutation, it’s able to not only re-infect the person, but use the antibodies to enter the cells. This causes massive damage to the immune system cells. The dengue fever virus is notorious for causing ADE. Since the vaccine causes the body to create antibodies, infection after the vaccine can be more dangerous than the initial infection itself. Part of the process of creating a vaccine beyond studying the virus is making sure ADE doesn’t happen.
The human body and the immune system are complex systems. They interact with outside pathogens all the time and react accordingly. Given the diversity of the human genome, vaccines must be safe for the majority of the population before commercial production and distribution. This is why during the COVID-19 pandemic, the best way to stay safe and healthy and reduce the transmission of the virus is isolation, quarantine, and social distancing. Until we develop a vaccine, these are our best defenses against the virus.