Question

why vaccines covid-19 difficult to prepare and taking so long?
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Answer 1

Because These diseases spreads from a "viruses"so vaccines of virus is difficult to prepare because viruses change their antigen so we cannot prepare vaccines easily so it's difficult .

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Answer 2

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• The World Health Organisation said this week it may be 18 months before a vaccine against the coronavirus is publicly available.

• This kickstarted efforts to develop vaccines around the world, including at the University of Queensland and institutions in the US and Europe.

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