Moderna vaccine booster appears to neutralize South Africa, Brazil COVID-19 variants

LOS ANGELES - Moderna announced on Wednesday that data from an ongoing trial of its COVID-19 vaccine booster found it was effective against variants of the virus, including the B.1.351 variants first identified in South Africa and the P.1 variants first identified in Brazil.

Moderna says a single dose of its vaccine given as a booster to previously fully vaccinated individuals "increased neutralizing antibody" responses against both variants. 

The data is from an ongoing trial analyzing various strategies for vaccine boosters that would be used to neutralize virus titers or concentrations of the coronavirus that can still infect cells. 

Participants in the study were given the vaccine boosters approximately 6 to 8 months after their initial shots. 

"We are encouraged by these new data, which reinforce our confidence that our booster strategy should be protective against these newly detected variants," said Stéphane Bancel, chief executive officer of Moderna. 

Moderna says as more data is revealed on this ongoing trial, the company will continue to make "as many updates to our COVID-19 vaccine as necessary to control the pandemic."

Despite the positive news out of the ongoing trial, CDC Director Dr. Rochelle Walensky said that variants of the coronavirus are a "wild card" that could set back the Unites States’ progress on the pandemic, the Associated Press reported on Wednesday. 

In an interview with FOX Television Stations on April 6, Dr. Anthony Fauci, the nation's leading expert on infectious diseases, said there’s a worrisome "wild card" factoring into the calculation of whether booster shots will be needed down the road for concerning variants. 

RELATED: Lack of vaccines in other parts of world puts US at risk, could prolong pandemic, experts say

Fauci explained that while vaccinating the majority of the U.S. is an important goal, the longer the novel coronavirus is allowed to spread and replicate, the greater the chances more transmissible and more deadly variants could emerge. 

The possible emergence of coronavirus variants capable of evading immunity imparted by COVID-19 vaccines would put the chances of herd immunity at risk and prolong a devastating ongoing pandemic.

"If we suppress it in the United States or in the developed world, that’s going to be great," Fauci said. "Now, this brings up an important question: As long as you have virus replicating anywhere in the world, the chances of developing variants are considerable, which will ultimately come back and could perhaps negatively impact our own response. That’s one of the real prevailing arguments for why we need to make sure the whole world gets vaccinated – not just the people in the developed world."

The CDC is now recording an average of about 350,000 new cases each week, 35,000 hospitalizations and over 4,000 deaths.

Recently, teams of experts projected COVID-19's toll on the U.S. will fall sharply by the end of July, according to research released by the government Wednesday. But the risks posed by virulent variants remain a real concern.

RELATED: COVID-19 toll in US projected to drop this summer, but variants could set back progress

The Centers for Disease Control and Prevention paper included projections from six research groups. Their assignment was to predict the course of the U.S. epidemic between now and September under different scenarios, depending on how the vaccination drive proceeds and how people behave.

With COVID-19 deaths, hospitalizations and cases plummeting since January, many states and cities are already moving to ease or lift restrictions on restaurants, bars, theaters and other businesses and talking about getting back to something close to normal this summer.

The paper doesn't look past September, and scientists cannot say for sure what the epidemic will look like next fall and winter because it's not known how enduring vaccine protection will be or whether variants of the virus will prove to be a greater problem.

Like the flu, COVID-19 could increase as people move indoors in the cold weather.

The Associated Press contributed to this story.