France’s top health body will on Friday say 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, two sources aware of the plans said.

Reuters had reported on Wednesday that the Haute Autorite de la Sante (HAS), in charge of setting out how vaccines approved by the European Medicines Agency (EMA) should be used in France, was contemplating this possibility.

“The HAS has now decided to proceed with the plan, the two sources said. Two mRNA vaccines, one from Pfizer and BioNTech and one 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 viral vector vaccines such as AstraZeneca’s use a common cold virus to carry DNA instructions for doing the same thing”, - writes Reuters