Page 139 of The Bone Code

“Where to begin?”

“Wherever you like.”

“What do you know about vaccine production?”

“Let’s assume nothing.”

“First off, all commercially available vaccines in the U.S. are made by private-sector manufacturers. For influenza vaccines, each company uses one of three production technologies. I believe EBFV refers to egg-based flu vaccine, CBFV to cell-based flu vaccine, and RFV to recombinant vaccine. Do you understand the difference?

“No.” Scribbling like mad.

“The EBFV method has been around for more than seventy years and is currently the most frequently employed. It’s used to make the common flu shot, an inactivated or killed vaccine, and the live attenuated or weakened vaccine used in nasal sprays.”

“How does it work?”

“The process begins with the CDC or some accredited partner laboratory providing a private-sector company with what’s called a CVV, a candidate vaccine virus. The company injects these CVVs into fertilized hen’s eggs, then incubates them to allow time for replication. They then harvest fluid from the eggs, inactivate the viruses, and purify the antigen. Do you know what an antigen is?”

“A protein that triggers the production of an antibody.”

“Yes. So that’s the process for flu shots. For nasal sprays, the live attenuated influenza vaccines—”

“LAIVs?”

“Yes. The viruses are alive but weakened. Are you still with me?”

“I am.”

“You understand that I am greatly oversimplifying.”

“I appreciate that.”

A beat to appraise my response. Then, “The cell-based method is also used to make inactivated flu vaccines.”

“The flu shot again.”

“Yes.”

“As with EBFV, CBFV production is multiphased. First, the CDC provides influenza viruses that have been grown in cells, not eggs.The manufacturer then injects the CVVs into cultured mammalian cells and allows them to replicate. The liquid is then collected, and the antigen is purified.”

“The difference is the use of animal cells versus chicken eggs.”

“Exactly. Recombinant flu vaccines are made synthetically and do not require a CVV. First, scientists obtain DNA, meaning genetic instructions, for making something called hemagglutinin, HA in your notes. HA is an antigen found on the surface of influenza viruses. It triggers the human immune system to create antibodies that specifically target that virus. Do you follow?”

“I do.” I actually did.

“The DNA for making the flu virus HA antigen is then combined with baculovirus, a virus that infects invertebrates. The result is an RFV.”

“A recombinant flu vaccine.”

“Yes.”

“Why baculovirus?”

“Its role is to transport the DNA instructions for making the flu virus HA antigen into the host cell.” When I didn’t reply, “Once the recombinant virus enters an approved FDA host cell line, it gives instructions to produce HA. The antigen is grown in bulk, collected, purified, then packaged as flu vaccine.”

“People get the flu shot, produce antibodies, and voilà! Immunity.”

“Basically.”