Boosters Are Found Effective on Omicron --- Third dose of Pfizer and Moderna Covid-19 vaccines offers protection, data show

"Vaccines and booster shots offer superior protection from the Delta and Omicron variants of Covid-19, according to three new studies released by the Centers for Disease Control and Prevention.

The data back up earlier findings supporting booster shots and offer the first comprehensive insight into how vaccines fare against the Omicron variant of the coronavirus.

In one of the studies published Friday, a CDC analysis found that a third dose of either the vaccine from Pfizer Inc. and BioNTech SE or Moderna Inc. was at least 90% effective against preventing hospitalization from Covid-19 during both the Delta and Omicron periods.

During the Delta period, vaccine effectiveness against hospitalization from Covid-19 was 90% from two weeks until about 6 months after dose two, 81% from at least six months after dose two and 94% at least two weeks after a booster dose. When Omicron was dominant, vaccine effectiveness against hospitalization for the same periods were 81%, 57% and 90%, respectively.

"Those who remain unvaccinated are at significantly higher risk for infection and severe Covid-19 disease," CDC Director Rochelle Walensky said. "Protection against infection and hospitalization with the Omicron variant is highest for those who are up to date with their vaccination, meaning those who are boosted when they are eligible."

An additional study published in Nature also supports booster doses and backs up previous findings from Pfizer and BioNTech showing that a third dose of their vaccine neutralizes Omicron but that its two-dose regimen is significantly less effective at blocking the virus.

According to the study published Thursday, two doses of the Pfizer-BioNTech vaccine provided little neutralizing antibody immunity against Omicron infection even at one month after vaccination, but a third dose offered more than 50% protection.

Separate research the CDC published Wednesday showed that among patients in California and New York during the Delta wave, prior infection provided more protection against Covid-19 than vaccination, though both offered significant defense from the virus. The data were collected before Omicron's emergence and the widespread booster campaign, so many people were likely experiencing some waning immunity from vaccination. The CDC said the findings couldn't be applied to the Omicron wave.

The agency also said in that report that vaccination was the safest way to acquire immunity against the virus because contracting Covid-19 carries the risk of serious illness or death, even for people at lower risk.

Separately, the Food and Drug Administration approved Gilead Sciences Inc.'s antiviral drug remdesivir for people with mild-to-moderate Covid-19 symptoms who are at high risk of developing severe cases. The drug, known by the brand name Veklury, was first approved in 2020 to treat people hospitalized with Covid-19.

The FDA said the approval was based on a study showing that 0.7% of patients taking remdesivir required hospitalization, compared with 5.3% of subjects who received placebos." [1]

1. U.S. News: Boosters Are Found Effective on Omicron --- Third dose of Pfizer and Moderna Covid-19 vaccines offers protection, data show
Schwartz, Felicia; Schechner, Sam; Kamp, Jon. Wall Street Journal, Eastern edition; New York, N.Y. [New York, N.Y]. 22 Jan 2022: A.6.