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Moderna is planning on creating a vaccine booster to help combat new variants. Patrick T. Fallon/AFP/Getty Images
  • New variants of the coronavirus containing mutations could diminish the effectiveness of the vaccines.
  • On Monday, the pharmaceutical company Moderna announced it is already working on a booster shot for its COVID-19 vaccine.
  • Messenger RNA (mRNA) vaccines can be easily tweaked, so even if a variant were to evade the vaccines, the shots could be easily modified to target emerging mutations.

All data and statistics are based on publicly available data at the time of publication. Some information may be out of date.

Moderna is already working on a booster shot to target the new variant detected in South Africa (the B.1.351 lineage), the company announced Monday.

Though the original two-dose regimen is expected to guard against new variants, the biotechnology company is testing an additional booster shot to determine whether it can produce more neutralizing antibody titers that protect against emerging variants.

There’s been growing concern that new variants containing mutations within the spike protein, the part of the coronavirus that latches onto our cells, could diminish the vaccines’ effectiveness.

The vaccines produce a broad immune response, so scientists expect the existing vaccines to provide a high degree of protection, even against variants with spike mutations.

Messenger RNA (mRNA) vaccines can be easily tweaked, so even if a variant were to evade the vaccines, the shots could be easily modified to target emerging mutations.

Dr. Onyema Ogbuagu, a Yale Medicine infectious disease doctor and principal investigator of Yale’s Pfizer COVID-19 trial, says it’s effortless to tweak mRNA vaccines.

“That can happen in two days, literally,” Ogbuagu said.

When you know the structure of a protein — as scientists do with these emerging variants — then you can produce a new mRNA template that targets the protein.

This new type of vaccine technology, used in the Moderna and Pfizer vaccines, is easier and faster to modify than traditional vaccine technologies.

Viral vector-based vaccines would be much more difficult to tweak, says Ogbuagu.

Thomas Duszynski, MPH, the director of epidemiology education at Indiana University’s Richard M. Fairbanks School of Public Health, says developing a new vaccine will take some time to develop “because you still have to do the clinical phases and testing for safety and efficacy.”

The modified doses would need to go through testing to show the immune response generated protects against clinical disease.

“The easy part is making the vaccine. The hard part is doing the human clinical trials to show that it prevents against the variant,” Ogbuagu said.

It’s unclear how rigorous that process would be.

The Food and Drug Administration (FDA) may want the modified vaccines to go through the whole clinical testing process again, but there may be an abridged way to do it.

Ogbuagu says it will be interesting to see if regulatory officials are “satisfied with immune response studies or if they’d want to see the hard clinical data that the immune response protects against clinical disease.”

That entire process is much more rigorous and takes a lot of time and effort, Ogbuagu said, noting this would be the more reliable path forward.

New doses would also need to be mass manufactured, distributed, and administered, which could introduce additional delays.

The current vaccines are thought to be efficacious against the variants, says Duszynski.

If that holds true, new vaccines may not be necessary.

Scientists originally hoped the vaccines would be at least 50 percent effective and were pleasantly surprised when the studies found the mRNA vaccines to be around 95 percent efficacious, says Duszynski.

Even if a variant slightly diminishes the high efficacy of the current vaccines, it wouldn’t render them useless.

Duszynski compared it to how we deal with the flu vaccine.

“The efficacy can range from 40, 50, 60, 70, 80 percent depending on the mutations that occur with the flu virus. And we don’t go out and change a vaccine if it’s 60 percent because some immunity is better than no immunity at all,” Duszynski explained.

Our current vaccines produce a broad immune response that will most likely confer a high degree of protection against new variants.

That efficacy threshold hasn’t been established, according to Duszynski.

More research about the current mutations and the current vaccine and their interaction is needed.

Either way, Moderna seems to be 10 steps ahead, so we will be prepared if a variant significantly impacts vaccine efficacy.

“It’s not a bad strategy, right,” Duszynski said, “but there’s the danger that you may not need it, and you’re spending resources on something you don’t need.”

Moderna announced Monday that it is already working on a booster shot to target the new variant detected in South Africa (the B.1.351 lineage). Scientists expect the vaccines to protect against variants. If a variant were to diminish the effectiveness, messenger RNA (mRNA) vaccines could be quickly tweaked to target new mutations. That said, it could take some time to test the new vaccines to ensure they’re safe and prevent clinical disease.