The race against COVID-19 has become more urgent as new, potentially more contagious variants emerge.

Feinstein Institutes for Medical Research virologist Dr. Bettie Steinberg says scientists weren't surprised by the emergence of the new COVID-19 strains from the U.K. and South Africa. While she doesn't work specifically on those strains, she says they do appear to have a higher rate of infection.

"And we think that it's because they bind better to the cells in your nose, but we're not certain that that's the only thing," says Steinberg. "Maybe they also produce more particles, which means if you're near someone who is infected you're going to be exposed to a higher dose."

And although Britain's prime minister has suggested that the U.K. strain may be more deadly, scientists in the U.S. say there's no clear evidence to suggest that.

Moderna says its vaccine will provide protection against the new strains, but it is less effective against the South Africa strain. To be proactive, Moderna's CEO announced the company will, "Test an additional booster dose of its COVID-19 vaccine..." and is also "...advancing an emerging variant booster candidate."

Scientists say the bottom line is the less virus that's out there, the less ability it has to mutate and the less we all have to worry about the effectiveness of the vaccines.

"Let me put this into perspective ... the polio vaccine is 70 years old. That virus mutates as well, but the vaccine still works and it's a 70-year-old vaccine. The same is true for the measles," says Northwell Health Critical Care Medicine Director Dr. Hugh Cassiere.

The FDA says in order for a COVID-19 vaccine to be approved, it had to be at least 50% effective. The Pfizer and Moderna vaccines are at 95%, so scientists say even if there is less protection against a certain strain of the virus, there is still protection.