COVID Vaccine breakthrough

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Across
  1. 6. an important stage in the development of something
  2. 7. when something like this has never happened before it is __________
  3. 8. hospital workers are ______ to the virus more than everybody else.
Down
  1. 1. the noun we get by adding a suffix to the verb 'develop'.
  2. 2. to admit something is true
  3. 3. a substance put into someone's body to prevent disease in the future.
  4. 4. give official permission for something.
  5. 5. if you have the right to have something you are ______ for it.
  6. 9. He has all the typical flu _______s - a high temperature, headache, and so on.