The flu vaccine – who needs it, and when to get it

South Africa's influenza season typically starts somewhere around the beginning of autumn and runs through the winter, most often peaking in the middle of that stretch. The exact start varies year to year, and the NICD tracks and announces it.

The vaccine takes about two weeks to produce protection, so the useful window is before the season builds rather than once everyone around you is already ill. Early autumn is the usual advice.

Anyone can have it, and in some years supply in the public sector is prioritised for those at highest risk of severe illness.

• Adults over 65.
• Pregnant women, at any stage of pregnancy — this also protects the newborn for the first months of life.
• People living with HIV.
• Anyone with a chronic condition: diabetes, heart disease, chronic lung disease including asthma and COPD, kidney disease, liver disease, or a weakened immune system.
• People who are significantly overweight.
• Healthcare workers, and anyone living with or caring for someone in the groups above.
• Children over six months with chronic conditions.

The flu vaccine reduces the chance of catching influenza and, importantly, reduces the severity if you do catch it — fewer hospital admissions, fewer complications like pneumonia. It is not a guarantee of not getting flu, and how well it matches the circulating strains varies from year to year.

• It does not protect against the common cold, which is caused by entirely different viruses.
• It does not protect against COVID-19, which has its own vaccine.
• It cannot give you flu. The injected vaccine contains no live virus.

A sore arm for a day or two is the usual experience. Some people get a mild fever, headache or aches for a day — an immune response, not an infection.

Most influenza is miserable and self-limiting: rest, fluids and paracetamol for the fever and aches. Antibiotics do nothing for it.