[RiseofAsia]

Obviously, you can observe the vaccine is not effective on ppl with underlying conditions(reported), obseity or other reasons? 

It means if your body health is not so good shape. Vaccine or no vaccine is actually doesnt make any difference.
Better wear your mask properly 才是上策。
Dont talk when you are in a crowded place such as in the MRT/Bus/Mall

Like Jac, better remind him to stay at home if possible...he is a die hard fan of this team.

Improve your blood circulation by doing exercise.
I recommend 拉筋运动。