Dr. Anthony Fauci speaks about the Omicron variant of the coronavirus during a press briefing at the White House in Washington DC, USA, December 1, 2021.
Kevin Lamarck | Reuters
White House chief medical adviser Dr. Anthony Fauci said on Friday that laboratory tests strongly suggest that booster shots will provide cross-protection against a “wide range” of Covid-19 variants, but noted that this has yet to be proven.
The booster shots “markedly” increase antibody titers against the virus species, Fauci said at a White House press briefing on Friday. The third shots also increase the so-called memory B cells and T cells, a line of defense created by the immune system to ward off the virus.
Memory B cells create antibodies to fight bacteria and viruses, and T cells target and destroy other cells infected with the virus.
“There is every reason to believe that if you get the vaccine and the boosted vaccine, you will have at least some degree of cross-protection,” Fauci said. “Very likely against serious illness, even against the omicron variant.”
Fauci’s remarks came as the world battles a new, heavily mutated version of the Covid-19 omicron.
This variant has about 50 mutations, more than 30 of which are related to the spike protein, which is the mechanism used by the virus to attach itself to human cells. Several mutations are associated with higher transmission and decreased protection of antibodies, according to the World Health Organization.
The US has joined the list of at least 38 countries with confirmed cases of the omicron variant, the World Health Organization said Friday. More than a dozen cases of the variant are now reported in at least six U.S. states after Nebraska officials confirmed six new cases on Friday.
Amid growing concerns over the omicron, the Centers for Disease Control and Prevention on Monday stepped up their recommendations for Covid-19 booster vaccines, telling all adults that they “should” get an extra dose. New CDC guidelines require everyone 18 and older to receive an additional shot six months after their initial Pfizer or Moderna series, or two months after their first Johnson & Johnson shot.
The Biden administration has also encouraged the use of Covid-19 booster shots, promising to provide them with up to 100 million eligible Americans.
To help roll out, he pledged: “More information, more appointments, more hours, more time and more sites to visit.”
To date, more than 41 million Americans have already received the vaccine, including half of eligible seniors, the White House said Thursday.
Health officials in the United States and around the world remain concerned that the omicron variant could reduce the effectiveness of vaccines to some extent.
A November study published in the journal Science found that the Pfizer vaccine’s effectiveness in preventing infections dropped from 86% to 43% between February and October. The study also found that the Moderna vaccine dropped from 89% to 58%, while the J&J vaccine dropped from 86% to 13% against infection.
But the Pfizer booster dose has provided 95% protection against symptomatic infection in clinical trials involving 10,000 people.