Almost a week after omicron, the new coronavirus variant, emerged as a variant of concern, scientists around the world don’t yet know the extent of its threat.
Answers to basic questions about the variant — if it’s more transmissible than others like delta, if it causes more severe disease, or how responsive it is to current vaccines — may be about two weeks away.
“We’re going to be at the mercy of time,” said Katelyn Jetelina, a Dallas-based infectious disease epidemiologist with UTHealth School of Public Health. Jetelina also writes the blog Your Local Epidemiologist.
The omicron variant, first identified in Botswana in early November, has several mutations on its spike protein — the “key” with which the virus attaches to human cells, she said.
If these mutations, or mutations on a variant to come, render vaccines less effective, manufacturers like Pfizer and Moderna have at least three distinct paths to pursue — the “worst-case scenario” of which could take about three months, Jetelina said.
Path 1: Create an omicron-specific vaccine
When a new variant emerges, scientists pay special attention to the variant’s spike proteins — the knoblike protuberances that give the coronavirus its crown-like appearance. That’s because the spike proteins serve as the mechanism with which the virus connects to human cells. The omicron variant has more than 30 mutations on its spike protein, Jetelina said.
Because the vaccines from Pfizer and Moderna target the virus’s spike protein, omicron’s mutations could make it more difficult for the body’s immune system to recognize and respond to the variant. “Maybe it’s, ‘Hey, you look like a cousin,’ ” said Russ Jones, chief epidemiologist at Tarrant County Public Health.
If omicron’s or a future variant’s mutations do render the body’s immune response less effective, the mRNA vaccines from Pfizer and Moderna are “tweakable,” Jones said.
They work by delivering instructions to the body to create a spike protein akin to the spike proteins on a coronavirus. The immune system then responds to those spike proteins, creating antibodies that interrupt the spike proteins’ ability to attach to a person’s cells. Later, if a vaccinated person is exposed to the real virus, her body’s immune system recognizes and attacks the spike proteins.
After researchers study the makeup of a new variant’s spike protein, they can adjust the instructions the vaccines deliver to the body, Jones said.
Pfizer and Moderna have announced they’re working on an omicron-specific vaccine, just in case. Both companies estimate the process could take about three months.
Path 2: Repurpose a ready-made variant-specific booster
A less time-intensive option could be distributing vaccines already in the works, Jetelina said.
Pfizer and Moderna had already created vaccine formulas specific to other variants of concern before scientists discovered omicron. Formulas specific to the beta variant, which the WHO labeled a variant of concern in December 2020, could be especially relevant for omicron, Jetelina said. The omicron and beta variants have similar mutations.
“I think the key question there is, ‘Would that vaccine work?’ We’ve already tested it with a lot of people,” she said. “Could we just start distributing that one?”
On Friday, Nov. 26, the same day the WHO categorized omicron as a variant of concern, Moderna announced it would “rapidly expand testing” of its variant-specific formulas to determine if they could neutralize the threat of omicron.
Before the shots can go into arms, the U.S. Food and Drug Administration would still need to approve the newest formulas.
Safety won’t be an issue, according to Dr. Mohanakrishnan Sathyamoorthy, a local physician who chairs the department of internal medicine at the TCU and UNTHSC School of Medicine. Sathyamoorthy and a cohort of physicians from north Texas recently received approval from the FDA to start clinical trials on a potential COVID-19 treatment.
The necessary tweaks to current mRNA vaccines are so negligible they wouldn’t compromise the safety of existing vaccines, he said. The real question will be efficacy. The new formulas would need to be tested in a lab setting and then in a smaller group of people, rather than the thousands typically required in the vaccine approval process, to see if they produce a sufficient immune response against omicron, he said.
Although the flu vaccine undergoes similar tweaks each year, the FDA has yet to codify this rapid of a review process, he said.
“An ongoing, global pandemic, with rapid evolution of variants, intersecting with the speed to which we can develop mRNA therapeutics has never happened in medical history before,” he said.
Path 3: Up the dosage of a vaccine already in use
The simplest and quickest path, which would “cut off a lot of manufacturing and distribution corners,” would be to simply increase the dosage of current vaccines, Jetelina said.
For example, Moderna has already tested a higher-dose booster shot in healthy adults, according to the company’s press release.
Scaling up the vaccine’s dosage could further spur the body’s production of antibodies, which would increase the likelihood that the antibodies would disrupt a virus from attaching to a human cell, Jetelina said.
Echoing this message, the Centers for Disease Control and Prevention announced Monday, Nov. 29, that all eligible adults should get a booster shot. People in Tarrant County can look for vaccination sites near them through the county health department’s website.
Regardless of the path omicron or a future variant prompts, Jetelina takes courage from the dexterity of the body’s immune system and the worldwide cohort of scientists working for a solution. Her message — for people to get boosted or vaccinated — remains consistent amid questions about omicron.
“We already have a massive problem today in the United States with delta, so we do not want to add fuel to our fire,” Jetelina said. “We need to get our fire addressed right now. And that should be our No. 1 priority while the science unfolds in the background with omicron.”
Alexis Allison is the health reporter at the Fort Worth Report. Her position is supported by a grant from Texas Health Resources. Contact her by email or via Twitter. At the Fort Worth Report, news decisions are made independently of our board members and financial supporters. Read more about our editorial independence policy here.