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The rise of the egg-based vaccine

created Apr 1st 2020, 12:01 by ThanhTuyn


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288 words
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Scientists started exploring the use of eggs in vaccine production in the 1930s. Researchers in England conducted the first trials on their armed forces in 1937, and the year after the US found it could protect its military with the flu shot. A working egg-based vaccine was ready for the US public by the 1940s.
Here's how it work today: The US CDC and other labs partner with the WHO to choose certain virus strains to send private vaccine manufactures. The flu can mutate and strains can change each year, meaning new vaccine are needed for every flu season. The selected virus is infected into a fertilized hen's egg, where it incubates and replicates for few days - just as it would do inside a human host. Scientists then harvest fluid containing the virus from the egg. They inactivate the virus so it can no longer cause disease, and purify it, leaving scientists with the virus antigen. The antigen is the crucial element - it's a substance released by the virus that triggers your immune system to respond. That's how the vaccine prepares your immune system for a real infection.  
The entire process, from the arrival of the egg to the publicly available vaccine, takes at least six months, according to the CDC.
As the coronavirus pandemic spreads, scientists and governments around the world are racing to develop a vaccine - but eggs won't be the answer. Due to having different receptors and other characteristics, the novel coronavirus isn't able to replicate inside eggs the way flu viruses can. But more than 20 potential vaccines using a range of non-egg technologies are now in development, and can then rapidly produce large amounts of antigen,  according to the WHO.

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