FRANKFURT Jan 25 (Reuters) - AstraZeneca's COVID-19 vaccine is not very effective for people over 65, German coalition sources told tabloid Bild and Handelsblatt, a step which calls into question its suitability in mass vaccination programmes.

German officials fear that the AstraZeneca vaccine may not be approved by European Union authorities for use in those over 65, the German tabloid said in its online edition.

It marks another potential blow for AstraZeneca, which developed its shot with Oxford University. It told the EU on Friday it could not meet agreed supply targets up to the end of March. (Reporting by Edward Taylor; Editing by Dan Grebler)