Canton Zurich is struggling to find enough senior citizens to fill appointments.
The canton has the capacity to vaccinate 90,000 in April - but so far, every eighth spot is free, and there are those in younger age groups who have registered and are waiting for a date.
The cantonal government councillor, Natalie Rickli, has tweeted calling for all those over 65 to register as they have 18,000 spare places this month.
But the health office does point out Zurich has already vaccinated 140,000. The canton says if there are still spare places in the next few days, they may move up the dates so younger people can get a dose.
Anyone over 16 can register to get a vaccine.
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