The Covid-19 variant could make herd immunity more difficult, says BioNTech

A more contagious version of the virus means that more people than initially expected should be vaccinated to stop its spread, said Ugur Sahin, CEO of BioNTech. The Pfizer-BioNTech vaccine is now underway in the US and the UK and is expected to be launched in the European Union starting next week.

Herd immunity occurs when a sufficient proportion of a population has been immunized by vaccination or after being infected, effectively ending the spread of the disease. The threshold at which the immunity of the herd is realized varies between diseases.

That threshold is related to the speed of viral spread, known as R. Most experts agree that the immune threshold for coronavirus is between 60% and 70% of a population.

If the new variant – which is thought to have originated in the UK but has now spread in small numbers to a handful of other countries – will increase the R’s number, the threshold for collective immunity will rise and governments will more vaccines are needed to stop the infection, Dr. Sahin said on Tuesday.

“If the virus becomes more effective in infecting people, we may even need a higher vaccination rate to ensure that normal life can go on without interruption,” he said.

If the new strain becomes predominant and the R number increases, countries may face additional outbreaks even after 70 percent of their population has been immunized, Dr. Sahin said. But in this case, the severity of the spread would be greatly reduced, allowing a gradual return to normal life, he said.

The Pfizer-BioNTech vaccine, which has now been given to more than a million people worldwide, is very likely to be effective against the new variant of coronavirus, said Dr. Sahin. It will take about two weeks to confirm this through testing, he said, adding that the company will publish the resulting data.

“We have scientific confidence that the vaccine could protect, but we will only know it when the experiment is complete,” he said.

The Pfizer and BioNTech vaccine works by injecting genetic material known as messenger RNA or mRNA into the body, which then alerts the immune system to a protein used by the virus to cause infection. The variant discovered in the UK has nine mutations, said Dr. Sahin, but only 1% of the proteins targeted by the vaccine have changed – making the vaccine unlikely to become less effective.

The vaccine has already been shown to be effective against 20 other known mutations that have occurred in recent months, he added.

If a new mutation makes the vaccine ineffective, BioNTech may develop another adapted to the new coronavirus variant in six weeks, according to Dr. Sahin. However, it is unclear whether regulators, such as the US Food and Drug Administration, would require a new vaccine to undergo new testing and a new authorization process.

In Europe, the BioNTech-Pfizer vaccine will be marketed starting this week under the Comirnaty brand name. Dr. Sahin said the name is derived from the words Covid, mRNA, community and immunity.

Write to Bojan Pancevski at [email protected]