This August, the CDC reported that the highly infectious delta variant may reduce efficacy of Pfizer-BioNTech and Moderna’s mRNA vaccines from roughly 91 to 66 percent. And while the delta variant continues to account for the overwhelming majority of cases in the U.S., some researchers claim that the lambda and mu variants could further dampen vaccine protection from symptomatic and asymptomatic infection. (Those findings, however, largely come from recent preprint studies that haven’t yet received peer review.)
Still, it’s currently unclear when current vaccine formulas will no longer work against certain variants, says Krishna Mallela, a pharmaceutical scientist and structural biologist at the University of Colorado Anschutz Medical Campus who has studied how mutations impact COVID-19 vaccines and treatments. “At this time, the ultimate goal is [understanding] how long these vaccines developed against the wild-type virus will still work for the next variant,” Mallela says. “The other way of putting it is: Can we predict the next variant?”
The current roundup of vaccines still offer considerable protection against severe illness and death, but their shrinking benefits have prompted calls for booster shots and other efforts to curb transmission. And an entirely vaccine-resistant variant may be on the horizon: Last month, Pfizer CEO Albert Bourla said he’s preparing the company for that possibility.
