Studies Demonstrate Omicron Variant Partially Evades Pfizer Protection


  • The Omicron variant partly escapes the protection offered by the Pfizer vaccine.
  • Tests in lab dishes from people who had been fully vaccinated with Pfizer’s vaccine showed the Omicron variant could evade the immune protection built by the vaccine — but not completely.
  • There’s a lot of variation from person to person when it comes to antibodies generated by vaccination.
  • Other studies looking at immune protection against variants have shown many of the Covid-19 vaccines create very strong immune protection that provides a cushion of extra immunity.

 The Omicron coronavirus variant partially evades the Pfizer vaccine’s protection, but patients who have been infected and then vaccinated are expected to be adequately protected, according to South African researchers as reported by CNN.


According to Alex Sigal of the Africa Health Research Institute in Durban, who led the study team, boosters are also likely to protect people.

It’s the first study to look at how the Omicron virus might behave in persons who have been vaccinated.

In lab dishes, tests using samples from 12 patients who had been fully vaccinated with Pfizer’s vaccine revealed that the Omicron variation may partially circumvent the vaccine’s immunological protection.

On Twitter, Sigal stated, “There is a very big decline in the neutralisation of Omicron by BNT162b2 [Pfizer/BioNTech] immunity relative to the ancestral virus.”

“The escape of Omicron from BNT162b2 neutralisation is only partial. The combination of previous infection and vaccine still neutralises the infection ” added he.

Fantastic news 

Sigal told CNN that the findings are encouraging.

“I felt this was fantastic news.” In a telephone interview, Sigal stated, “I expected worse.” He said that the mutations that characterise the Omicron variety appeared to allow it to bypass vaccination protection to a larger extent.

However, the results of the experiment show that it does not. “This isn’t a wholly escaped variety,” he explained. “It is undeniably evasive. It is unquestionably horrible. However, it appears to me that there are options for dealing with it.”

The studies were carried out by Sigal’s team using human lung cells. They stated in a study posted to an online preprint site that blood from six participants who had been infected and subsequently immunised was better able to eliminate the virus. It has not been subjected to peer review.

“Previous infection, followed by vaccination or booster, is likely to raise neutralisation levels and give protection against severe disease in Omicron infection,” Sigal’s team concluded.

Neutralising antibodies 

The study did not include people who have been infected with the virus.

It discovered a 41-fold reduction in the amounts of neutralising antibodies against Omicron in some of the samples when compared to those created against one of the virus’s earlier strains — though it’s unclear whether this translates to a decline in real-world protection.

According to Sigal, that figure will almost definitely change when more samples are evaluated. When it comes to antibodies produced by vaccination, there is a lot of diversity from person to person.

The Beta variety, which prevailed in South Africa until recently, likewise evades immune defence, according to the researchers. They added, “The results we offer herewith Omicron reveal substantially more broad escape.”

While the scientists did not test the Omicron virus variation against the blood of vaccination booster recipients, Sigal believes that persons who have been fully vaccinated and then boosted will be effectively protected from the Omicron version’s severe sickness.

He stated, “My sense is that if you get a booster, you’re protected, especially against serious sickness.” “It took a hit — a bigger hit than we’ve seen before — but it didn’t reduce it to insignificant levels.”

Immunological protection 

Other investigations of immunological protection against variants have found that several of the Covid-19 vaccines provide a cushion of extra immunity, such that even if a variant manages to evade some of the immunity, there is still enough to protect patients from severe sickness. That appears to be the situation with Omicron as well, according to Sigal.

Importantly, the virus continues to attack human cells through the same molecular gateway it has always used: the ACE2 receptor.

“Can you imagine what might have happened if this virus had found a different receptor to connect to?” Sigal wondered. “All of our immunizations would have been a waste,” he continued.

Sigal is keen to point out that this is a very preliminary study with only 12 persons and live virus samples developed in a hurry. “In just a few weeks, we went from collecting materials to conducting studies to publishing something. It’s insane, “ he stated

The researchers intend to analyse more samples and compare them to various vaccines, including the Johnson & Johnson vaccine, which was widely used in South Africa.

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Source: CNN


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