It takes the immune system about six to eight weeks to respond to flu vaccination. This means that the best time to be vaccinated against the flu is in mid-March to the end of May – before the flu season starts. Should you be vaccinated?
Most people benefit from the vaccination, but some need it more than others. These include: people aged 65 or older, especially if they are living in a retirement home; anyone with a heart problem; anyone with a respiratory problem, such as asthma or emphysema; anyone with a chronic illness such as anaemia, diabetes or kidney failure; those whose immunity is suppressed, including persons with HIV infection; children and teenagers (6 months to 18 years) on long-term aspirin therapy; women in their 2nd and 3rd trimesters of pregnancy; and caregivers and close contacts of any of the above.