WHO Says Vaccines - Including Pfizer - Work 'Better Than Expected' vs Omicron

The data regarding the Omicron variant continues to suggest better than expected results. 

WHO reports that the Pfizer as well as the AstraZeneca vaccines appear to offer some protection against Omicron. This suggests that Moderna and possibly other vaccines will retain efficacy against Omicron, as well. Boosters appear to be increasingly important, but it is not clear that new, Omicron-specific vaccines will be necessary. JL

Carolyn Johnson in the Washington Post and the BBC report:

Existing vaccines should still protect people who contract the Omicron variant from severe Covid cases, World Health Organization (WHO) says. Results, based on blood tests, were "better than I expected of Omicron." Omicron's ability to escape vaccine antibodies is "incomplete." Companies are retooling their vaccine to create a version that focuses the immune system against omicron, but have not decided whether it will be necessary, similar to steps they took to respond to the beta and delta coronavirus variants.

Post A booster shot could prove pivotal in helping control the omicron variant of the coronavirus by raising virus-fighting antibodies high enough to block the virus, vaccine makers Pfizer and BioNTech announced in a news release Wednesday.

The early data, which is not yet peer reviewed or published, suggests that two shots may not be sufficient to prevent infection from omicron and echoes a finding published Tuesday afternoon by leading scientists in South Africa.

Both studies suggest that higher levels of antibodies — whether triggered by a booster shot or a previous infection in addition to vaccination — would be protective.

Like the South African scientists, the pharmaceutical companies took blood samples after vaccination and found that virus-fighting antibodies took a big hit against omicron. For people with only two shots, the levels were low enough to leave people susceptible to breakthrough infections. The lessened effectiveness of the two-shot regimen means it “may not be sufficient to protect against infection with the Omicron variant,” the companies said.

But as many scientists have argued, vaccines trigger multiple prongs of the immune system and the companies said people who had received two shots of their coronavirus vaccine would still probably be protected against severe disease because of T cells, immune-system fighters that kill infected cells.

“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’s chief executive, said in a statement. “Ensuring as many people as possible are fully vaccinated with the first two dose series and a booster remains the best course of action to prevent the spread of COVID-19.”

 

The companies are retooling their vaccine to create a version that focuses the immune system against omicron, but have not decided whether it will be necessary — similar to steps they took to respond to the beta and delta coronavirus variants. The new data won’t, by itself, determine whether that version is needed, but it provides a clue by showing that building the wall of immunity very high — by boosting antibodies higher — could be enough to protect people. 

The companies estimate it would take about 100 days to begin shipping a new vaccine, and Bourla said this week a new version could be ready by March, if needed. They project being able to manufacture 4 billion doses next year, regardless of whether it is the original version of the vaccine or an updated one.

The new study follows the release Tuesday afternoon of a South African study that was both sobering and a relief to many scientists. That study, of blood samples from a dozen vaccinated people, showed omicron’s formidable capacity to dodge a primary line of immune defense, but also suggested that the vaccines retain some protective power in people who were vaccinated and previously infected.

BBC Existing vaccines should still protect people who contract the Omicron variant from severe Covid cases, a World Health Organization (WHO) official says.

It comes as the first lab tests of the new variant in South Africa suggest it can partially evade the Pfizer jab.

Researchers say there was a "very large drop" in how well the vaccine's antibodies neutralised the new strain.

But the WHO's Dr Mike Ryan said there was no sign Omicron would be better at evading vaccines than other variants.

"We have highly effective vaccines that have proved effective against all the variants so far, in terms of severe disease and hospitalisation, and there's no reason to expect that it wouldn't be so" for Omicron, Dr Ryan, the WHO's emergencies director, told AFP news agency.

He said initial data suggested Omicron did not make people sicker than the Delta and other strains. "If anything, the direction is towards less severity," he said. The new South African study - which has not yet been peer-reviewed - found the Pfizer/BioNTech vaccine may result in up to 40 times fewer neutralising antibodies against Omicron than against the original Covid strain.

But Omicron's ability to escape vaccine antibodies is "incomplete", said Prof Alex Sigal, a virologist at the Africa Health Research Institute, who led the research.

He said the results, based on blood tests from 12 people, were "better than I expected of Omicron".

Prof Sigal said vaccination, combined with previous infection, could still neutralise against the variant. That suggests boosters may bring a significant benefit.

Scientists believe previous infection, followed by vaccination or a booster, is likely to increase the neutralisation level and will probably protect people against severe disease.

More data on how well the Pfizer jab works against Omicron is expected to be released in the coming days.

There is no significant data yet on how the Moderna, Johnson & Johnson and other jabs hold up against the new variant.