There was mixed news on COVID vaccines Wednesday (December 15).
EU regulators have recommended Johnson & Johnson's shot for use as a booster dose.
The European Medicines Agency says it can follow vaccines from Moderna or Pfizer-BioNTech, in line with guidance on mixing shots.
That should help the rollout of booster programs, amid concern that the standard course of two vaccines is no longer enough.
However, a new shot from Sanofi and GlaxoSmithKline could be longer in coming than was hoped.
The pair say they won't get data from late-stage trials until the first quarter of 2022.
That's just the latest in a series of delays for a drug that they had hoped to get approved late this year.
GSK and Sanofi say they need more time to test their product on people who have not been infected with the virus.