The prospect of having a COVID-19 vaccine raises expectations and plenty of questions. While no one can pinpoint the elusive question of when there will be a vaccine, there are some questions that can be answered now.
Dr. Andrew Badley, head of Mayo Clinic's COVID Research Task Force, recently shared his expertise in this Q&A, starting with explaining the function of a vaccine.
WHAT IS THE GOAL OF A VACCINE?
The goal of a vaccine is to do one of two things. One is to prevent an infection. The second is to make an infection less severe if you get infected with that virus or organism. The way a vaccine achieves that is by creating an immune response that is specific for the virus or whatever it is you're vaccinating against.
There are two kinds of immune responses that we are interested in. The first kind is called antibodies. Antibodies are soluble and are present in plasma, and their job is to bind to the virus and neutralize it so it can't infect a cell. The second kind of immune response we're interested in is called a T cell response. And T cells are those cells of the immune system that kill cells we don't want. The goal of a T cell in the context of an infection is to kill those cells that are infected, and those infected cells essentially become virus factories.
WHAT CONSTITUTES A SAFE AND EFFECTIVE VACCINE?
Typically, what we will do is controlled clinical trials. A number of people get the vaccine and a number of people don't get the vaccine. And the hope is that those who get the vaccine get infected less frequently, and when they are infected, they get less sick.
On the safety side, there are a variety of side effects that are associated with any medicine or any therapy, some of which we can predict and some of which we can't predict. It's important to have controlled observation of people who get the vaccine to see whether or not there are side effects that are unintended.
HOW IMPORTANT IS POST-MARKETING SURVEILLANCE OF A VACCINE?
Monitoring long-term side effects of any therapy is critical. After a product is approved by the Food and Drug Administration and sold as a product, then they go into a process called post-marketing surveillance.