Eggs that stop you catching f lu

Coffee break 1

QUESTION How are flu viruses ‘netted’ for the purpose of making vaccines?

CREATING the flu vaccine involves a remarkable global collaboration: some 142 National Influenza Centres in 113 countries collect samples and data on the viruses.

They monitor which strains are making people sick, how fast they are spreading and how well previous vaccines have worked.

The results are sent to one of five major World Health Organisation (WHO) centres: the Francis Crick Institute in London and ones in Atlanta, Melbourne, Tokyo and Beijing.

Scientists then determine which strains of the ever-changing virus are most likely to dominate the upcoming flu season.

This process must be done several months before winter, to give enough time to create the new vaccine.

Once identified, the virus must be harvested to create sufficient quantities of vaccine. Viruses are incubated in fertilised chicken eggs, a tried-and-tested process.

Tiny needles inject live viruses — one of the three or four strains of flu virus that will monopolise the season — into the fertilised chicken eggs, which provide the environment in which the virus will multiply over three days.

These serums are later mixed so that each vaccine jab contains all the flu strains.

It takes approximately one egg per dose of vaccine, which means around 100 million fertilised eggs are needed globally to create the seasonal flu vaccines.

J. Alleyne, Oxford.

QUESTION When and why was it decided there should be 12 members of a jury panel?

FuRTHER to earlier answers, I like the story of the graffiti that reportedly appeared on the walls of the cells under the Old Bailey.

It read: ‘ I have just been convicted by 12 people too stupid to avoid jury service.’

Peter Turnbull, Leeds.