Researchers advise people to take the flu vaccine while they are healthy, not during the disease, and after full recovery for persons infected with covid-19. The vaccine takes two weeks to provide full protection to its users.
Vaccines are aiming at the protection of healthy individuals. Therefore the vaccine will be given to all healthy individuals - precisely as we do in vaccinating newborns against common infections at different ages of their life.
It does not matter for protection, as influenza vaccines don't work. However, it your decision whether to take any vaccine or not. In general, you should take any vaccine when you are healthy, particularly after the effect of steroids (dexamethasone) wanes down and cytokine storm due to COVID-19 has died. Hyper innate and adaptive immunity due to COVID-19 can cause side effects with a partially purified influenza vaccines. Suppression of immune response due to steroids will interfere with achieving protective response to a vaccine,