An egg can produce a dose of flu vaccine. Can it be used for a new crown virus vaccine?
Currently, the major influenza vaccine manufacturers in the
world are mostly egg-based, because the cost is relatively low.
Imagine that each egg is a closed, sterile bioreactor, and
with the highly industrialized breeding industry in developed countries, the
cost can be lowered. The final extracted and isolated antigen component of an
egg is almost just a vaccine.
According to CNN reports, there are many secret farms in the
United States that have tens of millions of chickens used to make vaccines. For
national security reasons, the locations of these farms will not be made
public.
Hundreds of thousands of eggs are shipped by truck to
designated locations every day, protected by dedicated security personnel and a
multi-million dollar security system funded by the US government. These eggs
are not used for breakfast, they are a common source of flu vaccine.
For the past 80 years, many pharmaceutical companies
worldwide have relied on eggs to produce flu vaccines.
According to data from the Centers for Disease Control and
Prevention (CDC), as of the end of February this year, about 174.5 million
doses of influenza vaccine have been distributed in the United States, of which
an estimated 82% are egg-based.
If one egg can produce a single dose of vaccine, this means
that in the flu season alone, the United States may have consumed 140 million
eggs.
US Government Investment for Epidemics
In response to the annual flu season and possible epidemics,
the US government has invested tens of millions or even hundreds of millions of
dollars over the past 15 years to ensure there are enough eggs for vaccination.
But now, the world is facing a new crisis-the new crown
virus. According to data from Johns Hopkins University today, the number of
confirmed cases in the United States has exceeded 120,000 and Italy has
exceeded 90,000. This virus has infected more than 500,000 people worldwide and
caused 23,000 deaths.
There is no vaccine against the new crown virus. Because it
is different from the flu virus, traditional methods such as eggs do not work.
While scientists are racing to find a cure, America's huge egg stocks will not
help.
Egg-based vaccine
It goes back to the 1930s, when scientists began to explore
the use of eggs in vaccine production.
In 1937, British researchers conducted the first test in
their army, and in the same year, American researchers also discovered that the
army could be protected by a flu shot.
In the 1940s, an effective egg-based vaccine came out.
In July 2007, eggs were being placed on shelves in Sanofi
Pasteur's factory.
The US CDC and other laboratories have partnered with the
World Health Organization (WHO) to select specific virus strains to be sent to
private vaccine manufacturers. Influenza viruses mutate and strains change
every year, which means new vaccines are needed every flu season.
The selected virus is injected into fertilized eggs and
incubated and replicated for several days. The scientists then extracted the
virus-containing fluid from the virus, inactivated the virus so that it was no
longer pathogenic, and purified it to obtain the viral antigen.
Antigen is a vital element. It is a substance released by the
virus and can trigger the immune system to respond. This is how vaccines
prepare the immune system for a true infection.
CDC on Egg Vaccine
According to the United States CDC, the entire process from
eggs to the vaccine provided to the public takes at least six months. The U.S.
government's vaccine comes from a handful of pharmaceutical companies who get
eggs from secret farms. A spokesman for Sanofi Pasteur, the largest flu vaccine
maker in the United States, said the locations of the farms were
"proprietary information" and said it was "safely
sensitive."
Eggs are not cheap either
According to a 2017 report by the US Government
Accountability Office (GOA), the US Department of Health and Human Services
(HHS) has signed a three-year contract with a company for $ 42 million to
ensure the supply of quality eggs throughout the year.
This is just a company in a period. HHS has signed contracts
with a few manufacturers and egg farms since 2005, which means there may be
more contracts worth tens of millions of dollars. And these eggs are not cheap,
and if the supply chain is affected, it will mean a shortage of key flu
vaccines across the United States.
As a result, these eggs have a series of security measures.
According to the GOA report, part of this $ 42 million
contract requires vaccine manufacturers to have both a "physical safety
plan and a biosafety plan to provide protection against human and natural
threats."
It seems like a lot of money is spent on eggs, but according
to the US CDC, the annual cost of hospitalization and treatment caused by the
flu is about $ 10.4 billion.
Pan Liewen, Scientific Director of the Public Health
Laboratory at the University of Hong Kong, said the eggs could be used not only
for flu vaccines, but also for the development of vaccines for other diseases.
It depends on the disease, as some virus strains cannot hatch in eggs.
Why the egg method is not suitable for the new crown virus vaccine?
John Nicholls, a clinical professor of pathology at the
University of Hong Kong, said that with the spread of the new crown virus
pandemic, scientists and governments around the world are racing to develop
vaccines, but eggs are not the answer.
"Because of different receptors and other
characteristics, the new crown virus cannot replicate in eggs like the
influenza virus," Nicholls said.
In addition to the imminent problem of the new crown virus,
the US government has been promoting the use of non-egg alternatives in recent
years. In September last year, Trump signed an executive order requiring
medical institutions to expand the use of alternative production methods.
"One reason officials are looking elsewhere is that the
six-month production period is too long. During this period, not only has the
pandemic spread globally, but the virus injected into eggs also mutates,
reducing the effectiveness of the vaccine Sex. "
Another problem is that the supply chain is actually very
fragile.
"If there is H5N1 bird flu, it will cause a large number
of chicken deaths, and the supply of eggs will drop significantly, and there
will be problems in obtaining enough eggs to make vaccines," he said.
The GOA report warned that it would take about 12 to 18
months to establish a supply of eggs sufficient to deal with seasonal or
pandemic influenza. But in such a rapidly spreading epidemic, authorities can't
wait that long, and there aren't so many chickens and eggs now.
The WHO says more than 20 new crown virus vaccines using a
range of non-egg technologies are currently under development. Some of these
are mRNA vaccines, which do not require actual samples of the virus or its
proteins to produce nucleic acids (drugs / vaccines) with a genetic code that
guide the body's own cells to synthesize certain proteins from the virus to
trigger an immune response. Others use recombinant DNA technology, which
produces genes that exactly match viral proteins and then quickly produces
large amounts of antigen.
Many egg-based flu vaccine companies have joined the ranks.
H1N1 flu vaccine produced by Sanofi Pasteur in October 2009
Fauci, the chief infectious disease physician in the United
States, said in February that it will take at least a year for the new crown
virus vaccine to be effective and obtain the necessary approvals for widespread
distribution.
Generally, clinical trials are divided into two phases. The
first phase involves dozens of people and will last about three months. The
second phase involves hundreds of people and will last another 6 to 8 months.
At present, China and the United States have started a phase
1 coronavirus vaccine trial.
Pan Liewen said, "We still have a lot to learn about the
new crown virus. Therefore, the extensive technology used to develop vaccines
provides us with a better opportunity to find effective vaccines. This is why I
say I agree with diversity because You never know which plan will succeed. It's
dangerous to put all your eggs in one basket."
Author's Bio
 |
| Dr. Shawna Reason |
Education: MBBS, MD
Occupation: Medical Doctor / Virologist
Specialization: Medical Science, Micro Biology / Virology, Natural Treatment
Experience: 15 Years as a Medical Practitioner
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