The government gets its vaccines from a handful of manufacturing companies, which source their eggs from numerous farms in secret locations. The farms’ locations are “proprietary information,” said a spokesperson from Sanofi Pasteur, the biggest flu vaccine manufacturer in the US, citing “security sensitivities.”
The eggs don’t come cheap: the Department of Health and Human Services (HHS) spent $42 million on a three-year contract with one company to ensure a year-round supply of high-quality eggs, according to a 2017 report
from the US Government Accountability Office (GOA).
That’s just one company from one time period; the HHS began contracting a handful of manufacturers and egg farms in 2005, meaning there are likely many more contracts worth tens of millions of dollars.
And these eggs are precious: if the supply chain is compromised, it could mean a nationwide shortage of crucial flu vaccines.
So, obviously, the eggs have bodyguards.
Part of that $42 million contract required that the vaccine manufacturer had “both a physical security program and a biosecurity program to provide protection against man-made and natural threats,” according to the GOA report.
That might seem like a lot of money to spend on eggs, but each year the flu costs the US about $10.4 billion in hospitalizations and treatments, according to the CDC.
And the eggs aren’t only useful for flu vaccines — they could potentially be used to develop vaccines for other illnesses, said Leo Poon, head of public health laboratory sciences at Hong Kong University (HKU). It just depends on the illness, as some virus strains can’t incubate inside eggs.
Why the egg method won’t work for a coronavirus vaccine
As the coronavirus pandemic spreads, scientists and governments around the world are racing to develop a vaccine — but eggs won’t be the answer, said John Nicholls, a Hong Kong University clinical professor of pathology.
Due to having different receptors and other characteristics, the novel coronavirus isn’t able to replicate inside eggs the way flu viruses can, Nicholls said.
Even beyond the immediate problem of the coronavirus, US officials have been pushing for non-egg alternatives in recent years.
US President Donald Trump signed an executive order
last September requiring health agencies to expand the use of alternative production methods.
One reason officials are looking elsewhere is the six-month production time can be too slow. Not only could an illness spread globally during that time, but the virus injected into the egg could mutate and make the vaccine less effective, said Poon.
Another issue is that the supply is vulnerable to deadly avian flus. “If there’s a pandemic of H5N1 (avian influenza), it can kill chickens substantially and there will be a huge drop in egg supply, and you will have a problem getting enough eggs to make the vaccines,” Poon said.
The GOA report warned that it takes about 12 to 18 months to establish an egg supply large enough for either seasonal or pandemic influenza. But in the case of a fast-spreading pandemic like this, authorities simply can’t wait that long — and there aren’t that many chickens and eggs immediately available.
More than 20 potential coronavirus vaccines using a range of non-egg technologies are now in development, according to the WHO.
Some of these are mRNA vaccines, which direct cells in the body to make proteins to prevent or fight disease using messenger ribonucleic acid, a molecule vital to the proper functioning of the body’s cells. Others use recombinant DNA technology, which produces an exact genetic match to proteins of the virus, and can then rapidly produce large amounts of antigen.
Even companies that traditionally make egg-based flu vaccines are jumping into the mix; Sanofi Pasteur said in February
it was working on a non-egg coronavirus vaccine.
Health officials warn it will take at least a year
before any coronavirus vaccine is proven effective and gets necessary approvals for widespread distribution.
Typically, clinical trials are broken into two phases. Phase 1, involving a few dozen people, would last about three months. Phase 2, involving hundreds of people, would last another six to eight months.
At least one Phase 1 coronavirus vaccine trial has now begun; the US study gave a dose
to the first participant on March 17. Over six weeks, each participant will receive two injections about a month apart in varying doses, to try to establish that the vaccine is safe and induces a desired response from participants’ immune systems.
There is still a lot we don’t know about the coronavirus, said Poon — so the wide range of technologies being used to develop vaccines gives us a better shot at finding one that works.
“That’s why I say I appreciate diversity,” he said. “You never know which one is going to work — it’s dangerous to put all the eggs in one basket.”