COVID-19 vaccine efficacy could depend on virus' mutation rate

Posted at 3:05 PM, Oct 07, 2020

As the COVID-19 pandemic progresses, researchers say it is important to track how the coronavirus mutates because it could affect the efficacy of a vaccine.

Like all living cells, viruses evolve their chemical make-up changes. In viruses like the flu, that happens frequently, which is why every year there is a new vaccine to treat whatever strain is expected to circulate. With COVID-19, however, those mutations happen much slower, according to research out of Arizona State University.

“One of the things we’re still keeping an eye on is the evolution of this virus because that virus is still around in the community,” said Dr. Efrem Lim, an assistant professor at ASU. “Everyone is coming in blind to this. This is a novel virus. This isn’t something we have seen before.”

In March, Arizona State University played host to our country’s fourth COVID-19 case. As soon as it was detected, Dr. Lim started studying how the virus mutates and sent his findings to the World Health Organization. It's something that still continues to this day.

“This virus, overall, mutates pretty slowly, which is a good thing,” said Dr. Lim. “However, we can have instances where the virus can have very large, dramatic, mutations, such as deletions in the genome.”

While rare, Dr. Lim says those mutations can be significant as it changes how the virus acts inside the body.

Currently, scientists are focusing much of their efforts on identifying ways to eliminate the function of the spike protein in COVID-19, as it is the way the virus binds to our cells and infects them (spike proteins are the stalks that protrude from the center of the virus that make it so recognizable).

“It is very good news that the virus is not changing rapidly,” said ASU virologist Dr. Brenda Hogue. “We will have to see over time, as the virus continues to circulate, as we put a vaccine into play, whether or not there will be any issues.”

Dr. Lim says right now there does not appear to be any issues because the virus mutates slowly, but he adds it could adapt to a vaccine once one begins to circulate.

He says more testing needs to be done to determine that, however.