Omicron vaccine: approval still a long way

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In the race against mutating coronavirus, manufacturers have presented what they see as positive clinical data on adapted vaccines. For example, Pfizer/Biontech and Moderna recently published results showing that their adapted boosters stimulate an efficient immune response even against the newer omicron sublines BA.4 and BA.5.

However, it is essential to note that the new vaccines are not specifically tailored to these variants but to the BA.1 subline, which is no longer circulating in Germany. There is now a debate about whether the approval process should not be shortened so that the preparations do not lag too far behind the evolution of Sars-CoV-2.

Pros and cons
There is evidence that infection with BA.1 does not protect particularly well against further infection with BA.4 or BA.5. Thus, one might conclude that the newer sublines are more likely to slip through the cracks even to a vaccine adapted to BA.1.

German Health Minister Karl Lauterbach (SPD) and Berlin virologist Christian Drosten recently advocated a vaccination campaign with up to 40 million people vaccinated before winter. Adapted vaccines could offer better immune protection against omicron sublines than existing preparations. At the moment, no one knows precisely which variants will dominate in Germany this winter.

The results published over the weekend by Biontech/Pfizer relate primarily to protection against BA.1. According to a news release, subjects who received a booster of an adapted vaccine showed significantly higher neutralizing antibody responses against BA.1 than with the existing Biontech/Pfizer vaccine. A total of 1,234 participants aged 56 and older participated in the study.

A Biontech spokeswoman, when asked, said no data have yet been published on how the adapted vaccines perform against currently occurring sublines such as BA.4 and BA.5 compared with the existing vaccine. However, according to the statement, preliminary laboratory studies have shown that both adapted vaccines are effective against viruses of the BA.4 and BA.5 sublines, albeit to a lesser extent than BA.1.

Differing opinions
Approval of such an agent is not expected until September at the earliest, partly because manufacturers must demonstrate in human studies that the tailored vaccine provides a real benefit. Now there is debate as to whether these studies are vital. The argument is that approval would be faster with fewer requirements, and there would be less risk that the virus would have mutated further by the time the vaccine was launched, making it easier to escape the vaccine’s effects.

Biontech CEO Ugur Sahin recently argued in the Financial Times for a much faster process that would not require additional clinical trials – similar to the flu vaccine, which is adjusted annually. That could save up to four months, he said.

Klaus Cichutek, president of the Paul Ehrlich Institute (PEI), which is responsible for vaccines in Germany, takes a different view. “If we prepare calmly for the fall wave, there is no reason to do without the relevant clinical data in humans,” he told the Welt am Sonntag newspaper. The approval practice could indeed be adapted in an emergency, but that is not the case now.