Omicron’s ‘incomplete escape’ of Pfizer jab’s protection – Expert Reaction

Early lab results from a small South African study suggest the Omicron variant may be able to bypass some of the antibody immunity brought about by the Pfizer vaccine.

Researchers studied samples from 12 double-jabbed people, finding a 41-fold drop in antibodies’ virus-blocking ability in some of the samples, compared to those generated against the earlier Beta strain. More research is needed to confirm what this might mean for real-life protection, including the impact of booster shots.

The research has not yet been formally peer reviewed. An advanced copy of the manuscript is available here.

The SMC asked experts to comment on the manuscript.

Dr Dianne Sika-Paotonu, Immunologist, Associate Dean (Pacific), Head of University of Otago Wellington Pacific Office, and Senior Lecturer, Pathology & Molecular Medicine, University of Otago Wellington, comments:

“The new SARS-CoV-2 variant Omicron has been spreading quickly across the globe and has been reported in countries close to Aotearoa New Zealand including Australia and Fiji.

“Researchers in South Africa had been looking to see whether Omicron escapes the immunity protection given by the Pfizer vaccine, and also whether the Omicron variant still binds to the ACE2 receptors to infect cells in the body.

“Their results just released, indicate that the ACE2 is still required for Omicron to enter into cells.

“Their results also indicate that a drop in immune protection given by the Pfizer vaccine occurs against the Omicron strain, when compared with infection caused by the ancestral version of the virus.

“For those who’d been previously infected with COVID-19 and who had also been vaccinated, considerable immune protection was retained.

“More information is still needed about Omicron, and whether or not it causes more severe disease, hospitalization and mortality when compared with the Delta variant of the SARS-CoV-2 virus.

“In the meantime, a maintained focus on vaccination, border controls and public health settings will be needed.

“We’re continuing to experience the impact of Delta, particularly for the most vulnerable. Please get vaccinated and tested and reach out to help others do the same.”

No conflict of interest.