Dr. Anthony Fauci, chief medical adviser to the Biden administration, said the Omicron variant of the coronavirus appears to be able to “evade” the protection of antibodies induced by vaccines, in an interview with ABC on Dec. 12.
“It appears to be able to evade some of the immune protection of things like monoclonal antibodies, convalescent plasma, and the antibodies that are induced by vaccines,” Fauci told “This Week” anchor George Stephanopoulos.
“Preliminary data show that when you get a booster, for example, the third shot of an mRNA [vaccine], it raises the level of protection high enough that it does do well against the Omicron,” Fauci said.
While Fauci noted that the “level of severity” with the Omicron variant appears to be “a bit less than that in the Delta,” he said confounding factors may be at play such as “underlying protection in the community due to prior infections.”
On Dec. 8, Pfizer/BioNTech revealed that three shots of their mRNA vaccine were able to neutralize the Omicron variant in a preliminary study.
“Although two doses of the vaccine may still offer protection against severe disease caused by the Omicron strain, it’s clear from these preliminary data that protection is improved with a third dose of our vaccine,” Albert Bourla, Pfizer chairman and CEO, said in a statement.
The study found a 25-fold increase in the level of antibodies in those who had received three shots as opposed to two Pfizer/BioNTech vaccines.
Furthermore, the Dec. 8 news release stated that 80 percent of the spike protein recognized by the immune system’s T cells will still be neutralized by the body’s T cells, meaning that “two doses may still induce protection against severe disease.”
The pre-print of a South African study (pdf) released earlier last week found that the two-shot course of the Pfizer vaccine induced a 22.5 percent efficacy against symptomatic infection by the Omicron variant which is “essentially compromising the ability of the vaccine to protect against infection.”
While the two-shot Pfizer series may not prevent infection with Omicron, it should still be “sufficient for protection against severe disease, although this estimate is difficult to validate,” according to the team led by lead researcher Alex Sigal.
Researchers based at the Africa Health Research Institute in Durban gathered blood plasma samples from 12 participants. The results showed that Omicron produced a 41-fold reduction in the level of neutralizing antibodies in those who had completed the two-shot Pfizer/BioNTech series compared with the original strain caused by the CCP virus (Chinese Communist Party virus).
According to Bloomberg, the team was the first to demonstrate that the Omicron variant could largely, but not entirely, evade antibodies induced by the Pfizer/BioNTech vaccine. The study supported Pfizer’s claim that a third booster shot could raise immunity.
Pfizer/BioNTech expects a “variant-specific vaccine” for Omicron to be available by March 2022.