Pfizer booster study improves mood over Omicron variant

Palestinian doctor prepares dose of Pfizer / BioNTech Covid-19 vaccine – Copyright AFP PETER PARKS

Sebastien ASH

Three doses of Pfizer-BioNTech coronavirus vaccine appear to be effective against Omicron variant, lab test has shown – encouraging news, even as Denmark and Britain announce new restrictions to stem rising numbers of cases.

In preliminary results released on Wednesday, the US and German companies behind one of the world’s leading gunfire to fight Covid-19 said a booster generated roughly the same level of potent antibodies against Omicron than that observed after a second dose with the initial strain.

But they warned that “the Omicron variant is probably not sufficiently neutralized after two doses.”

The announcement, which has yet to be peer reviewed, was described as reassuring by experts and came as the first independent data from labs around the world emerged indicating that the new mutations are more effective for escape immunity to infections and vaccines than those that came before them.

“We always have to be very measured and take a wait-and-see approach, but I think what we have is at least encouraging,” virologist Angela Rasmussen of the Canadian Organization for Vaccines and Infectious Diseases told AFP.

Blood samples from around 20 people who had received two doses of the current vaccine showed, on average, a 25-fold reduction in neutralizing antibodies from the original strain of the virus, the companies said.

But they added that another part of the immune response – from T cells – was probably still effective against the new variant, meaning people given two doses “may still be protected against severe forms of the disease.”

Vaccine makers are developing an Omicron-specific version of the jab, which they hope will be ready by March, but say the decision to mass-produce it will depend on the spread of the variant.

– New restrictions –

In Europe, Danish Prime Minister Mette Frederiksen has announced that she will extend the Christmas school holidays, cut back on nightlife and urge citizens to work from home as the country battles a sharp rise in infections.

“The plan is not to have a long shutdown,” she said, while acknowledging that a return to home offices would also be unwelcome for many.

His British counterpart Boris Johnson has also brought home work from home advice and vaccine passports for places such as nightclubs and stadiums. The new measures apply to England and were already in place in Scotland and Wales.

“We must be humble in the face of this virus,” he said, adding that it was “the proportionate and responsible thing to move to plan B in England”.

Johnson announced the strict measures while facing public anger over video footage of his assistants joking about an alleged illicit Christmas party in Downing Street during last year’s lockdown.

WHO chief Tedros Adhanom Ghebreyesus, meanwhile, summarized what scientists have learned about Omicron since it was first reported in South Africa in late November.

He escapes prior immunity well and it is possible that this will cause milder illness, he said.

But even though it’s confirmed to be less severe, the increased transmissibility of the variant – believed to be superior to that of the currently dominant Delta strain – means it could make many people sick.

– Three blows –

The news from Pfizer and BioNTech came after other preliminary results from a small study in South Africa suggested there was up to a 40-fold drop in the ability of antibodies from the same vaccine to neutralize Omicron, compared to an early strain.

Willem Hanekom, executive director of the Africa Health Research Institute, which conducted the study, said it was important to be “extremely careful” in interpreting the results as they only reflect a laboratory environment. , when real-world data was the real test.

Reductions in antibodies were also seen in studies by German and Swedish researchers, but they varied in magnitude.

Omicron has more than 30 mutations in the spike protein that dots the surface of the coronavirus and allows it to invade cells, and a high degree of immune evasion was widely anticipated.

But the fact that a booster appears to restore high protection has been welcomed by many experts and provides “strong support for the campaign to deliver three doses of the vaccine,” said Charles Bangham, immunologist at Imperial College of London.

While Omicron’s early positive reviews helped boost morale, particularly in global markets as fears of a further economic downturn faded, the emergence of the variant highlighted that the fight against the pandemic is far from over.

Covid-19 has officially killed more than 5.2 million people worldwide since it was first reported in late 2019, although the true toll is likely several times higher.

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