Vaccine makers already planning for COVID-19 variant spread

Even with the pace of vaccinations accelerating, some experts worry about a scenario where strains even more virulent than the one detected in South Africa start to emerge.

Video Transcript

- As health officials anxiously track the new variants of COVID-19, the question in the background-- how do you stop the virus from making an end run around the world vaccines? Even with the pace of vaccinations accelerating, some experts worry about a scenario where dangerous strains, like the one that emerged in South Africa, start to spread as quickly as another variant from the UK has already done. Dr. Catherine Blish is an infectious disease expert at Stanford.

CATHERINE BLISH: Then we have more trouble because we have a partially resistant variant with a chance for it to develop more mutations and become even more resistant.

- Companies have begun working on updated versions of their vaccines, with Moderna reportedly exploring a potential third dose booster shot for its two-part regimen, while Oxford AstraZeneca, whose vaccine performed poorly against the South African variant, says it's working to produce an update by the fall. Fellow Stanford infectious disease researcher Bali Pulendran says the modern RNA and virus-based vaccines have an advantage because their genetic formulas can be adjusted quickly.

BALI PULENDRAN: To generate a tweaked messenger RNA vaccine is, I think, not an issue. Companies are already thinking of doing that. And, in fact, some may already be doing it.

- And tweaking them might not mean going back to the drawing board. The FDA is finalizing plans for what could be smaller fast track approval trials for new formulas, leveraging the trial data that's already available.

BALI PULENDRAN: Not tens of thousands of people, a few hundred people who get this tweaked vaccine. And you can measure the quantity of neutralizing antibody.

- Other proposed strategies include possibly mixing and matching second doses from different vaccines. That's because different versions may activate the immune system in slightly different ways, potentially creating a strong overall effect.

CATHERINE BLISH: And so we might gain the benefit of some immunity to parts of the protein that aren't just that one little protein that sticks out.

- Many researchers believe current vaccines are in a solid position in the near term, in part because of the protection they offer against severe disease. But health officials worldwide will likely be watching for what some have described as a dangerous red line-- that would be if vaccinated patients begin turning up at hospitals with more severe infections, a sign that tweaked vaccines may be needed to protect against a shifting threat.