The WHO said Friday there was "no adequate data" on switching Covid-19 vaccines between doses, as France said under-55s who received an AstraZeneca first jab should get their second from a different vaccine.
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"There is no adequate data to be able to say whether this is something that could be done, so... interchangeability of vaccine was not something that we could give a recommendation on," World Health Organization spokeswoman Margaret Harris told reporters.
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