Fauci: 'Every Reason To Believe' Boosters Protect Against Omicron

Vaccination with a booster dose of COVID vaccine is expected to offer "some degree of cross protection" against the Omicron variant, said NIAID Director Anthony Fauci, MD, during a White House COVID-19 Response Team briefing on Friday.

While there are still a lot of unknowns when it comes to the new variant -- including how transmissible it is, the severity of disease it causes, and its ability to evade our immune systems -- Fauci, who is chief medical advisor to President Biden, anticipates answers will come in "a matter of days to weeks."

In the meantime, Americans can reduce their own risks against the variant by getting vaccinated, he said.

"Although we haven't proven it yet, there's every reason to believe that if you get vaccinated and boosted that you would have at least some degree of cross protection, very likely against severe disease, even against the Omicron variant," Fauci said.

In a brief presentation on Friday, he cited research showing that getting a booster "markedly increased the antibody titers against a wide range of variants."

Data on antibody titers before and after a third shot of Moderna in adults 18-64 showed a jump from 55 to 872 titers, approximately 28 days after a third shot -- even higher than their peak after the second shot, he noted. Titers similarly rose from 32 to 708 for adults 65 and older, 28 days after they were boosted, Fauci said.

The Pfizer-BioNTech booster produced similar results: a month after the third shot, 50% serum neutralization titers shot up from 241 to 1,321 in adults 18-55, and from 123 to 1,479 in adults 65-85, according to an October report in the New England Journal of Medicine.

Fauci also cited animal studies indicating that boosters drove up antibody levels by up to a factor of 20, and in doing so "broaden and strengthen the immune response," as one of his slides noted.

"When you look at the third dose, you increase the levels of neutralizing antibodies against all the variants" in addition to increasing levels of memory B cells and T cells, "which strongly suggest that boosters will give you cross protection against a number of variants," he said.

CDC Director Rochelle Walensky, MD, noted that the Omicron variant has now been detected in 40 countries. It has also been recorded in five states: California, Colorado, Minnesota, Hawaii, and New York. Although CDC is still working with state and local public health officials to identify cases in other states, Walensky stressed that 99.9% of current COVID-19 cases are due to the Delta variant.

She added that because of knowledge and experience from previous variants, plus the availability of "proven prevention methods" and additional treatment options, "we are in a far better position now than we were at this time last year."

To date, 21 million Americans have received a booster dose, said U.S. Surgeon General Vivek Murthy, MD, MBA.

On Thursday, the U.S. saw the highest number of vaccinations in a single day since May, reaching 2.2 million shots, according to Jeff Zients, White House COVID-19 Response Coordinator.

In addition, more than 4 million children ages 5-11 years have received the COVID-19 vaccine -- including his own 5-year-old son, Murthy said.

In an effort to help protect more children, Medicaid will begin paying healthcare providers for talking with families about vaccinating their children, Murthy said. This step, he suggested, "will help more families get connected to the personalized, trusted medical advice that they need and deserve."

In addition to vaccinating children, the administration is also focused on increasing booster shots through expanded outreach efforts, including a booster information toolkit, phone and text-banking, podcasts, letters, and social media -- using "just about everything short of carrier pigeons," he joked.

Finally the Biden administration announced an infusion of $20 million to support the Medical Reserve Corps on Thursday. President Biden's plan will also create over 60 emergency medical response teams as they prepare to face increasing case numbers this winter.

Like Walensky, Murthy emphasized that the U.S. is in a better place than it was last winter before vaccines and rapid tests were available.

"I feel both cautious and hopeful. We are on the right track and we're learning more about how to stay on the right track," he said.

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