FDA set to OK COVID-19 boosters for newer Omicron strains without completed human tests

 New COVID-19 booster shots are set to be authorized this week by the Food and Drug Administration (FDA) and will be available to most Americans before human testing has even been completed.

The shots have been modified to target the latest Omicron variant, but won't have finished testing in humans when the FDA makes the decision. Instead, the FDA is relying on data from other sources - like research in mice and older vaccines, the Wall Street Journal reported.

'Real world evidence from the current mRNA Covid-19 vaccines, which have been administered to millions of individuals, show us that the vaccines are safe,' FDA Commissioner Robert Califf said in a tweet last week. 

Califf also wrote that the FDA will rely on the totality of the available evidence in making a decision.

This includes, clinical trial data from other bivalent mRNA COVID-19 boosters, RWE from current COVID-19 vaccines administered to millions of people, and non-clinical data for the bivalent BA.4/5 vaccines.

Clinical trial data, which will be used for the clearance of the vaccines, is similar to what the approach the FDA uses regarding flu shots, which are updated annually to keep up with mutating strains. But some vaccine experts are not fans of the approach and believe it would be better to wait, rather than going with 'mouse data.'

Even though the Covid-19 virus has evolved, the vaccines first authorized for use in December 2020 in the US haven't been modified until now. 

'I'm uncomfortable that we would move forward—that we would give millions or tens of millions of doses to people—based on mouse data,' Paul Offit, an FDA adviser and director of the Vaccine Education Center at Children's Hospital of Philadelphia, told the Wall Street Journal.  

Dr. Offit also said the flu vaccines are different because flu viruses mutate so rapidly that shots from one year don't offer protection for the next, but for now, the COVID-19 vaccines continue to keep people out of the hospital.

The shots have held up so far against earlier strains of the virus, but have not been as effective against the newest Omicron subvariants like BA.5, researchers discovered.

So in June, health officials directed Pfizer Inc. and BioNTech SE, and Moderna Inc. to update their shots to target BA.5, an Omicron subvariant called BA.4.

Pfizer and rival Moderna both asked U.S. regulators this week to authorize modified versions of their booster vaccine — shots that are half the original recipe and half protection against BA.4 and BA.5, the newest versions of omicron.

The Food and Drug Administration ordered that recipe and now is evaluating what scientists call a 'bivalent vaccine,' with a decision expected soon.

Dr. Peter Marks, the FDA's vaccine chief, said last week that once authorized, the tweaked boosters could help right away — while BA.5 infections still are too high — as well as hopefully blunt yet another winter surge.

Marks told the Associated Press that the new boosters could rev up the immune system to prevent not just serious illness but maybe milder infections, too, like the original vaccines did earlier in the pandemic, before super-contagious mutants emerged.

'The hope here is that by better matching things, not only will we get that benefit or even more, but we'll also have that last for a longer period of time,' he said. 

But while FDA hasn't made a final decision, Marks said there's evidence that the updated boosters are safe and that waiting for more study of their effectiveness would risk another mutant appearing before they could roll out. 

'As we know from prior experience, strain changes can be made without affecting safety,' Dr. Califf said in a tweet.

However, Dr. Offit said he would like to wait for clinical-trial data showing the shots are effective before asking people to take them.

'If you have some evidence that this is likely to be of value, sure,' he said. 'But if you don't have evidence, and you know that the current vaccine does offer protection against severe disease, I don't think it's fair to ask people to take risks.'

https://www.dailymail.co.uk/news/article-11154635/FDA-set-authorize-new-COVID-booster-shots-Omicron-strains-without-completed-human-tests.html