What the Delta variant could mean for Covid-19 in the US

A coronavirus variant first spotted in India is poised to become the dominant one in the United States, where infectious disease modelers say it could cause a "resurgence" of Covid-19 later this year.

 

And it may already account for 1 in every 5 infections nationwide, experts say.

 

Dr. Rochelle Walensky, director of the US Centers for Disease Control and Prevention, told CNN last week she anticipates Delta will become "the predominant variant in the months ahead."

 

And that could be a few weeks — not months — away, according to William Lee, vice president of science at Helix, a company whose Covid-19 tests have helped track a number of variants.

 

In the two weeks leading up to June 5, CDC estimates that Delta was responsible for nearly 10% of US infections. And now Lee says it likely accounts for roughly a fifth of cases.

 

"It's so transmissible that, unless your vaccination rates are high enough, you will still have outbreaks," Lee said.

 

Infectious disease modelers are showing how a variant like Delta could make a Covid-19 comeback later this year.

 

Faced with a more transmissible variant, "it looks like we do see a resurgence late in the summer, or in the early fall," said Justin Lessler, an epidemiologist with the Johns Hopkins Bloomberg School of Public Health.

 

Lessler has been working with contributors from a dozen other institutions on the Covid-19 Scenario Modeling Hub to forecast the pandemic.

 

According to the model, getting 86% of eligible Americans vaccinated — meaning, those 12 and up — could avert more than 10,000 cumulative deaths by late November.