While many hens lay eggs that are decorated and eaten during Easter season, others work for global health and help produce hundreds of millions of flu vaccines all year long.
Martin Friede, the chief vaccine researcher at the World Health Organization (WHO) in Geneva, said every year, between 450 million and 500 million eggs are used for immunization shots.
And he told the German News Agency: “More than 90 percent of the world’s flu vaccine is being produced with the help of eggs.’’
Scientists rely on products that cannot be bought in supermarkets. The quality they need can only be found in special farms where hens are kept under strictly controlled conditions.
“It’s more expensive than producing your omelet eggs,’’ Friede said, adding that the chickens cannot be eaten. “Too scrawny,’’ he said.
WHO experts decide, twice a year, which influenza virus variants would dominate the next flu season. Laboratories then produce the necessary viruses and send them to vaccine factories, where they are injected into eggs.
After around 10 days, billions of copies of the virus have matured in the egg white. Then, they are deactivated with heat or chemicals, turning them into harmless but effective vaccines.
Researchers have long been looking for alternative host cell cultures, including cells from a dog’s kidney tumor and from insects.
According to Friede, the cell culture from the tumor could be reproduced infinitely. But these approaches are not yet ready for mass production.
“Eggs will definitely continue to play a decisive role in the production of influenza vaccine for the next 20 years,’’ Friede said.
