Vaccines, Boosters Should Protect Against Severe COVID, Even With Omicron: Fauci

Americans who are vaccinated and boosted against COVID-19 should have enough antibody protection to prevent severe illness if they become infected with the new Omicron variant, White House COVID response officials said Tuesday.

Omicron has caused concern among medical experts due to a "large number of mutations, around 50, much larger than previous variants," including some "anticipated to impact transmissibility and antibody binding," White House Chief Medical Advisor Dr. Anthony Fauci said during a media briefing.

It's too soon to tell how transmissible the new variant is and whether it can evade existing vaccines, Fauci said, but he noted that more than 30 mutations are in the spike protein of the virus. He referred to the protein as the "business end of the virus," because that's where the coronavirus attaches to and infects human cells.

However, officials are confident that the antibody levels produced by boosted vaccination will be enough to provide protection against hospitalization and death, Fauci said.

"Although partial immune escape may occur, vaccines, and particularly boosters, give a level of antibody that even with variants like Delta give you a degree of cross-protection, particularly against severe disease," Fauci said. "There's every reason to believe as we talk about boosters, when you get a level high enough that you are going to get at least some degree of cross-protection, particularly against severe disease."

The number of confirmed cases of Omicron has climbed to 226 in 20 countries, Fauci said, but he added, "I think you're going to expect to see those numbers change rapidly."

The Omicron variant has not yet surfaced in the United States, where the Delta variant of COVID-19 still reflects 99% of all samples analyzed, Dr. Rochelle Walensky, head of the U.S. Centers for Disease Control and Prevention, said during the briefing.

In the meantime, the CDC is expanding its surveillance program at four of America's busiest international airports — New York, San Francisco, Newark and Atlanta — so that targeted COVID-19 testing can occur for specific international arrivals, Walensky said.

Fauci expects that it will be two to four weeks before officials can provide more concrete information about the threat Omicron poses.

During that time, federal health officials will be growing that variant in the lab and then using some current antibody treatments — convalescent plasma and monoclonal antibodies — to get a "pretty good idea as to what the level of immune evasion is," Fauci said.

The United States will also rely on biologists in the countries where the Omicron variant is widespread, to see how sick it makes people and whether it starts to crowd out the Delta variant, Fauci added.

During the next few weeks, those biologists "are going to be getting a good feel as to what the competition of this virus would be with Delta," Fauci said.

In the meantime, Fauci and Walensky repeated President Joe Biden's call for widespread vaccination and adherence to social distancing methods like masking as the best way to prepare for a possible invasion of Omicron.

"Evidence has repeatedly shown that prevention strategies work," Walensky said. "With over 80% of our nation's counties still in substantial or high transmission, CDC continues to recommend wearing a mask in public indoor settings in these areas, washing your hands frequently, and physical distancing."

Sources

• Nov. 30, 2021, media briefing with: Anthony Fauci, MD, White House Chief Medical Advisor and director, U.S. National Institute of Allergy and Infectious Diseases

• Rochelle Walensky, MD, director, U.S. Centers for Disease Control and Prevention