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14 Dec, 2021 16:02

Study reveals how effective Pfizer vaccine is against Omicron

Study reveals how effective Pfizer vaccine is against Omicron

New analysis released from South Africa suggests that two doses of the Pfizer-BioNTech coronavirus vaccine are considerably less effective in battling the Omicron variant compared to earlier strains.

The study, published by Discovery Health in partnership with the South African Medical Research Council, was released on Tuesday and indicates that two doses of the Pfizer vaccine are only 33% effective against infection amid the current Omicron-dominated wave.

The study did show, however, that the vaccine (excluding booster shots) is effective against serious Covid infections overall, saying it provides 70% protection against “severe complications” from the virus that would require hospitalization. This level of protection, however, is down from a much higher 93% figure found during the previous wave of Delta variant cases. 

“Superb genetic surveillance by the Network for Genomic Surveillance in South Africa identified that Omicron infection accounts for over 90% of new infections in South Africa, and has displaced the formerly dominant Delta variant,” Dr. Ryan Noach, chief executive for Discovery, said. He added that the current Omicron wave “has a significantly steeper trajectory of new infections and test positivity rates.” 

The study looked at over 211,000 positive Covid-19 cases in South Africa, with 41% of those submitting test results having been fully-vaccinated with two shots of the Pfizer-BioNTech inoculation. Approximately 78,000 of the positive tests were for the Omicron variant, which was first discovered in southern Africa but has since been recorded in multiple countries. 

There is still very little known about the variant. These cases were all pulled from the first three weeks (from November 15 through December 7) in South Africa following the discovery of the new variant. 

People who previously had Covid-19 are at a “significantly higher” risk of getting re-infected with the Omicron variant compared to other known strains, according to the study. 

Health officials involved with the research warned that the results are preliminary as there is still much to discover about both Covid-19 and Omicron. 

“This is early data and requires careful follow up,” said Shirley Collie, chief health analytics actuary for Discovery Health. 

Since the discovery of Omicron, South Africa has seen an uptick in Covid cases, with their seven day rolling average rising from approximately eight new cases per 100,000 people in late November to about 34 new cases per 100,000 people on December 13.