Vaccines – August 19, 2020


Given the ongoing pandemic and talk of effective vaccines coming in the next few months/early next year, we wanted to cover this important topic today for Science Wednesday. To start, what exactly is a vaccine? You can think of it as a “sneak peek” for the immune system of key features of a virus before the actual virus invades the body. The goal is for the immune system to develop “memory” of a virus and then fight it effectively if and when the person gets infected. In the case of the COVID-19 disease, once “prepped,” the immune system can better recognize SARS-CoV-2 (the virus) when it invades, and stop it from getting into cells, replicating itself, and causing illness.
For SARS-CoV-2, an effective vaccine ideally needs to latch on directly or indirectly to the spike protein unique to coronaviruses (did you know: coronaviruses got their name because the viruses have spikes that look like a crown?). There are vaccines currently being tested in clinical trials using various methods. Rather than injecting coronavirus spike proteins directly, one method uses delivery of genetic instructions via messenger RNA (mRNA) that make their way into shoulder muscle cells near the injection site. There are different techniques for this: one vaccine delivers these mRNA genetic instructions via a tiny fatty envelope, while another does it using a weakened common-cold virus (called adenovirus). However it gets there, once there the mRNA instructs cells to produce coronavirus spike proteins, to trigger the immune response. Other vaccine types are using DNA (instead of mRNA) to induce human cells to produce virus proteins, while still more others are directly introducing viral proteins (but just fragments) into cells.
You may be thinking, is this all safe? While all the vaccines in development are using different approaches to see which one ends up being the most effective, none involve viruses that can actually multiply and cause disease. This would be unethical. Rather, vaccines currently in development are being designed to “sharpen” the immune system response through introduction of genetic instructions or viral proteins, as detailed above.
Thanks to vaccines, globally we have eradicated smallpox and nearly eliminated cases of polio. Many vaccine skeptics believe that vaccines make people sick, in large part because of fraudulent and discredited research (e.g., read more here about vaccines and autism: Research shows the opposite: vaccines save lives.