Three doses of a COVID vaccine may not be able to curb the rapid spread of the highly transmissible Omicron variant of COVID, warned Ugur Sahin, CEO of Germany-based BioNTech.

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According to the World Health Organisation (WHO), the variant, known to escape vaccine immunity, has spread to about 90 countries. "We must be aware that even triple-vaccinated are likely to transmit the disease. It is obvious we are far from 95 per cent effectiveness that we obtained against the initial virus," Euronews quoted Sahin. BioNTech partnered with US drugmaker Pfizer to develop the two-dose revolutionary COVID jab, based on mRNA technology. Despite this, Sahin noted that early data from the UK and South Africa are providing us with "reassuring information".

The latest research from South Africa, where Omicron was first reported, suggested that two doses of the Pfizer/BioNTech vaccine offered 70 per cent effectiveness in reducing the risk of hospitalisation. Israeli researchers have also found that the booster doses of the vaccine work against Omicron. "There will be a loss of effectiveness against Omicron over time, it's very likely, but it's still to be measured how quickly. I will not base predictions on preliminary laboratory data but on real-life data, which is much more appropriate," the German immunologist said.

Sahin said testing for COVID-19 is important, especially for the elderly and during winter, as are other protective measures such as mask-wearing, adding, "otherwise we will not be able to control the rapid expansion of this new variant". The German company is already designing a coronavirus vaccine adapted to the new variant, using Omicron's spike protein and its 32 mutations as an antigen. Sahin announced this should be ready by March, the report said. "We remain on track with our 100-day target, which means we should be able to deliver our first suitable vaccines to Omicron in March, subject to regulatory approval," he said.

Some researchers have voiced concern about the effect of these new vaccines as instead of boosting new immune defences, they could risk boosting inadequate ones. "This principle is an unproven hypothesis, personally, I don't think this is a real problem. The immune system has high adaptability and plasticity, and should be able to activate both, strengthening existing immune responses while generating new antibodies," Sahin said, adding "but we will obviously have to assess it."

Scientists at WHO have also predicted that Omicron has a "substantial growth advantage" over the Delta variant and it will soon take over Delta. It is still unclear how effective vaccines are against the new variant, the WHO said. Meanwhile, Moderna, which has also produced an mRNA vaccine, said that a booster dose of its vaccine appeared to be protective against Omicron. Moderna said that its research so far showed that a 50 microgram dose of its vaccine, which is the current amount for a booster jab, increased the level of antibodies 37-fold, compared with two doses. It also said a full dose of 100 micrograms boosted antibody levels 83-fold, it said.