What is the flu vaccine?

The influenza vaccine is still the most important way to either avoid influenza altogether, or to reduce its severity.

Vaccines commonly used are produced from a killed virus. Most vaccines are made from highly purified, egg-grown viruses that have been made non-infectious. It is important to remember that flu vaccines do not prevent the common cold.

Significant advances in the production of flu vaccines:

• First generation (1958) whole virus vaccines produced a satisfactory immune response but with a higher risk of side-effects.
• Second generation (1968) "split" virion vaccines contain the fragmented and purified particles from the virus, including the two surface proteins and the other viral constituents.
• Third generation "subunit" vaccines (eg Influvac, Vaxigrip) contain only the surface antigens (hemagluttinin and neuraminidase) and are devoid of other viral constituents thus reducing the protein load in the vaccine. This makes sub-unit vaccines less likely to cause side effects.
• Split and subunit vaccines are recommended for children since they have reduced side effects.
• The latest vaccine - from live viruses - is still in an experimental phase, but shows huge promise. Administered in the form of nasal drops, and with few side-effects, it might be ideal for children.

Read more:
Who should be vaccinated against flu?