I have a fever, cough, sore throat, and nasal congestion. I've been taking medication but it hasn't helped. Is the medicine fake? (Dinh Thanh, 50, Lam Dong)

Following repeated, prolonged flu infections, individuals with high blood pressure and diabetes are turning to flu vaccinations to mitigate the risk of reinfection and severe respiratory or cardiovascular complications.

Long, 13 years old, developed a cough with phlegm and nasal congestion for six days, experienced pain and weakness in both legs, and his muscle enzyme levels increased eighteen-fold due to myositis following a flu B infection.