Hi. Even though the risk of developing allergy to Covid (or any other) vaccine is slightly higher in people with known allergic tendencies, there is no special testing required before taking the vaccine. She can take the Covid vaccine. As a precautionary measure, it would be better to take the vaccine in a hospital setup where any allergic reaction, if it occurs, can be handled well. Only if she has had allergic reaction to any of the contents of the vaccine before, she shouldn't take the vaccine. I would recommend that she inform the doctor available at the vaccination site that she does have allergic tendency so that necessary precautions can be taken.