There is no data available at the moment to recommend other countries follow France's decision to "mix and match" different COVID-19 vaccines, the World Health Organization's regulation director Rogerio Gaspar told a briefing on Friday.
France's top health advisory body in charge of COVID-19 vaccines recommended on Friday that recipients of a first dose of the AstraZeneca shot who are under 55 should receive a second dose with a so-called messenger RNA vaccine.