UPDATE 1-France to recommend mRNA COVID-19 shots as second dose for some after AstraZeneca - minister

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PARIS, April 9 (Reuters) - France’s top health body should say on Friday that recipients of a first dose of AstraZeneca’s traditional COVID-19 vaccine who are under 55 should get a second shot with a new-style messenger-RNA vaccine, Health Minister Olivier Veran said.

“This should normally be confirmed today”, Veran told RTL radio, adding he did not want to announce the move ahead of a news conference by the body - the Haute Autorite de la Sante (HAS) - later in the day.

Veran said this was a precautionary measure that could evolve in time, pending the gathering of further data on the AstraZeneca shot. France would continue to encourage the use of the AstraZeneca vaccine, he added.

Two sources told Reuters on Thursday about the HAS’s upcoming announcement. Two mRNA vaccines, one from Pfizer and BioNTech and another from Moderna , are approved for use in France.

Messenger RNA vaccines prompt the human body to make a protein that mimics part of the virus, triggering an immune response, while traditional vaccines such as AstraZeneca’s use an inactivated virus to carry a protein from the pathogen - in this case the novel coronavirus - to do the same thing.

Confidence in the AstraZeneca vaccine has dropped in Europe since a very few, mostly young, recipients of the shot were found to have suffered extremely unusual blood clots. (Reporting by Sudip Kar-Gupta, Benoit Van Overstraeten and Matthias Blamont; Editing by Alex Richardson)