PHILADELPHIA (CBS) — New research that came out Monday reveals the COVID-19 vaccine is effective at stopping international variants. However, health officials now say those mutations appear to be more dangerous than first thought.

The variants appear to be more contagious. A growing number of health officials say wearing two masks can provide an extra layer of protection, but the vaccine remains the best prevention.

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Research from Moderna says its vaccine is effective against the COVID variant from the United Kingdom, but not as much in the one from South Africa. So now, Moderna will test booster doses tailored to fight the new strains.

“The vaccines we have, these mRNA vaccines, they illicit super awesome levels of antibodies and their reactivity drops from super awesome, to just awesome,” said Dr. Scott Hensley with the University of Pennsylvania. “Well, guess what? That’s good enough in neutralizing these variants.”

Dr. Hensley’s lab at UPenn is studying the COVID vaccine and immune responses.

“We need vaccinations and we need them fast,” Dr. Hensley said. “The only reason we have to worry about variants is because there’s so much virus out there and it’s going unchecked.”

The variant from the U.K. that’s spread into 20 states, is more contagious than the original virus, and now, scientists say, it appears to be potentially more dangerous.

“We need to assume now that what it has been circulating dominantly in the U.K. does have a certain degree of increase in what we call virulence, namely the power of the virus to cause more damage, including death,” said Dr. Anthony Fauci, chief medical adviser to President Joe Biden.

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In addition to the United Kingdom, COVID mutations have been found in South Africa and Brazil. They haven’t been detected yet in the U.S., but they’re a bigger concern.

“If you have a virus that is more transmissible and can partially evade the immune system, what that means is that some individuals who have already been infected with coronavirus are potentially susceptible to reinfection,” explained Dr. Hensley.

Because of the more contagious variants, Dr. Fauci joined other health officials in saying people should wear two masks. That’s not an official recommendation from the CDC, but researchers say that wearing a surgical mask under a cloth one provides maximum protection.

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