What’s the end goal of a vaccine? To provide lifelong immunity towards a certain disease. In order to do this, the vaccine must activate cells that produce antibodies. But for some viruses, this is easier said than done. HIV, for instance, mutates so frequently that the human body can’t catch up with each new version.
But as scientists learn more about the new coronavirus, one disturbing piece of information has emerged: immunity seems short-lived.
Antibodies in the blood
It’s normal for antibody levels to decrease in the bloodstream over time. After all, the body only needs to produce antibodies when there is an infection. However, this usually happens over a period of years, not months. And yet, there have been cases of reinfection in several COVID survivors. As such, scientists now aim to create a vaccine that will boost the antibody-producing branch of the immune system.
From what we know right now, COVID-19 creates a strong response from the innate immune system. This branch is responsible for immediate, general reactions to foreign invaders. For example, when you cut your finger and the area becomes red and swollen, that is the innate immune system at work. Unfortunately, this branch has no memory and does not produce antibodies. This means you’ll always get sick and experience symptoms, even if you’ve encountered the virus in the past.
RNA vaccines for COVID-19
Many of the vaccines in development are different from traditional vaccines. Instead of giving someone viral proteins or dead viruses, the new vaccines use temporary genetic material (RNA) to stimulate the adaptive immune system——the branch that produces antibodies and has memory. Scientists also think that booster shots might be necessary to bolster immune memory. The result would be that if the patient encounters the virus again, their body would create more antibodies, faster.