The arms race between the coronavirus and humanity continues to pick up steam. This week, Moderna announced that its modified vaccine meant to target a worrying variant first found in South Africa is now ready for testing. Pfizer/BioNTech is also set to test out their own contingency plan for new variants soon.
The variant discovered in South Africa last winter—known as B.1.351—has emerged as one of the most concerning to date. Like other recently discovered variants, such as B.1.1.7 (first found in the UK), B.1.351 is more transmissible than past strains of the virus. But B.1.351 has also shown more of an ability to evade a person’s immune response created by earlier infection or vaccination than other variants. Earlier this month, for instance, South Africa suspended its pending vaccination campaign with the Oxford/AstraZeneca vaccine, after early data suggested that it would only be minimally effective at preventing illness from B.1.351.
Moderna and Pfizer/BioNTech’s research so far has suggested that their vaccines will provide protection against B.1.351, but its effectiveness would likely be diminished. Out of an “abundance of caution,” Moderna announced last month that it would develop a version of their vaccine specifically tuned to B.1.351. On Wednesday, the company said that it has now shipped the new vaccine to the U.S. National Institutes of Health for testing in people.
Moderna initially plans to test out three different strategies against B.1.351. One study, already in progress, is testing whether a third booster dose of the original vaccine can improve a person’s immune response to the variant. The second will test a combination of the original and modified vaccine in a single booster dose. And the third will test the modified booster alone. They also hope to test whether the modified and/or combination vaccine can be effectively used as the primary vaccine series for people with no previous antibodies to the virus.
Not to be left out, Pfizer/BioNTech announced Thursday that they are starting their own clinical trial testing out a third booster dose with the original vaccine. They’re also in talks with federal regulators to have trials testing out their updated version approved as well.
The trials needed to vet these updated vaccines for public use won’t be anywhere near as large or lengthy as the ones that led to the original emergency use authorization for either mRNA vaccine. That’s because there’s plenty of data on the typical immune response created by the original vaccines from the large scale trials, so less work is needed to confirm the safety and effectiveness for any modified version. Additionally, researchers will be testing in the lab whether B.1.351 can evade neutralizing antibodies to the coronavirus collected from the blood of vaccinated volunteers.
Even before the emergence of these variants, scientists cautioned that any covid-19 vaccines we developed might need to be adjusted periodically, just to account for the evolution of the virus. Thankfully, the coronavirus doesn’t seem to mutate in relevant ways nearly as fast as the influenza virus, which requires a yearly-updated vaccine. So while it’s still important to keep ourselves as safe as possible from the pandemic for the time being, it’s also worth remembering that even these variants aren’t an insurmountable threat that we can’t do anything about.
Hopefully, we may not even need to rely on these modified vaccines for now, provided that daily new cases continue to drop sharply as more people get vaccinated.