Omicron Better Able to Evade Vaccines Than Earlier Variants


In a small study, Omicron appears to ward off vaccines, but those vaccines still carry plenty of wallop against the variant, and boosters enhance protection, say experts.

The Omicron variant of COVID-19 seems better able to escape the protection of the Pfizer/BioNTech vaccine than previous iterations of SARS-CoV-2, according to the first study that measures Omicron’s reaction to vaccination.

However—the study by the Africa Health Research Institute (AHRI)—actually underscores the need for vaccination, because it states that the vaccines do a good job of warding off the virus in people who’ve been previously infected and have gotten the vaccine. It’s the first study that looks at how Omicron fares against the vaccine and has yet to be peer reviewed.

AHRI’s executive director Willem Hanekom said in a statement that “most vaccinologists agree that the current vaccines will still protect against severe disease and death in the face of Omicron infection. It is therefore critical that everyone should be vaccinated.”

The AHRI study comes a day after Pfizer/BioNTech announced that laboratory studies demonstrate that serum antibodies induced by their COVID-19 vaccine neutralized the Omicron variant after 3 doses. Sera obtained from vaccines 1 month after receiving the booster vaccination neutralized the Omicron variant to levels that are comparable to those observed for the wild-type SARS-CoV-2 spike protein after 2 doses.

It also comes during a debate over the legitimacy of vaccine mandates in the United States. Many health care experts argue that private industry should mandate that their employees be vaccinated, or regularly tested. But vaccine mandates imposed by the Biden administration have not fared well when challenged.

On November 29, Judge Matthew Schelp of the U.S. District Court for the Eastern District of Missouri, ruled in favor of 10 states seeking an injunction to halt implementation of the Biden administration’s mandate that health care workers must be vaccinated. The ruling stated that “the Centers for Medicare and Medicaid Services (CMS) failed to adequately explain its contradiction to its long-standing practice of encouraging rather than forcing—by governmental mandate—vaccination.”

Amd just yesterday, as Reuters reports, the U.S. Senate voted 52–48 to overturn President Biden’s vaccine-or-test mandate for private industry. The bill now goes to the House of Representatives.

In the AHRI study, investigators tested the resilience of Omicron in blood from 12 people who’d gotten the Pfizer/BioNTech vaccine, 6 of whom had been infected by COVID-19. The AHRI’s Alex Sigal posted on Twitter that “just be clear on something…, this was better than I expected of Omicron. The fact that it still needs the ACE2 receptor and that escape is incomplete means it’s a tractable problem with the tools we got.”

The bottom line for Segal is that “there is a very large drop in neutralization of Omicron” with the Pfizer/BioNTech vaccine. Segal added on Twitter that “Omicron escape from BNT162b2 neutralization is incomplete. Previous infection + vaccination still neutralizes.” Nonetheless, there was a 41-fold reduction in neutralization against Omicron compared to the Beta variant, a substantial drop but investigators note that vaccines and boosters should be able to keep Omicron at bay.

The study may bolster the push by some medical experts to change the definition of fully vaccinated from 2 doses to getting 3.

Anthony Fauci, MD, the director of the National Institute of Allergy and Infectious Diseases and the chief White House medical advisor, tells CNN that it’s a matter “of when, not if” the definition fully vaccinated changes.

“I don’t see that changing tomorrow or next week, but certainly if you want to talk about what optimal protection is, I don’t think anybody would argue that optimal protection is going to be with a third shot.”

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