New York, Aug 29 (IANS): The US Food and Drug Administration (FDA) is expected to approve new covid-19 booster shots for newer Omicron strains this week, making them accessible to people in the country before any human testing is finished, the media reported.

The vaccines have been modified to target the most recent Omicron variant, but the US FDA won't have finished testing them on humans, the Daily Mail reported citing The Wall Street Journal.

The report mentioned that the FDA is instead relying on information from other sources, such as mice study and data from previous immunisation.

"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.

The official 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, the report said.

But some vaccine experts are not fans of the approach and believe it would be better to wait, rather than going with "mouse data", it added.