The more-transmissible Delta Covid-19 strain accounted for more than half of the coronavirus cases in the U.S. between June 20 and July 3, according to new data the Centers for Disease Control and Prevention released on Tuesday.
A CDC spokesperson told POLITICO surveillance data indicated the Delta variant jumped from 30.4 percent of cases for the two-week period ending June 19 to 51.7 percent between June 20 and July 3.
The sharp jump underscores the extent to which the Delta variant has spread throughout the country and raises questions about how the Biden administration plans to contain it at the national level. The Delta strain represented more than 80 percent of cases across Iowa, Kansas, Missouri and Nebraska between June 20 and July 3, according to the new CDC projections.
The administration is struggling to increase the vaccination rate in southern and some western states. While the number of doses administered edged up slightly in recent days, the overall national vaccination rate has plateaued. About 55 percent of Americans age 12 and older are fully vaccinated, according to CDC data.
CDC Director Rochelle Walensky warned last week that the Delta variant was a growing threat to the unvaccinated population and that it could eclipse the Covid-19 Alpha variant in the coming weeks. “Looking state by state and county by country, it is clear communities where people remain unvaccinated are communities that are vulnerable,” Walensky told reporters.
Biden health officials continue to point to data that shows that available vaccines from Pfizer, Moderna and Johnson & Johnson work well to protect against the variant and prevent severe diseases. The administration’s message on the Delta variant has remained constant for months: Get vaccinated, and you will be safe.
But early research from Israel released by the country’s health ministry on Monday appears to suggest the Pfizer-BioNTech vaccine is less effective against the Delta variant. The analysis found the vaccine’s efficacy against preventing infection and symptomatic illness fell to 64 percent while maintaining an efficacy rate of 93 percent against serious illness and hospitalization.
White House press secretary Jen Psaki told reporters on Tuesday the Israel data is “preliminary,” saying the “vast majority of data from larger assessments and larger studies shows that [the vaccine] is quite effective.”
“If it’s true that the vaccines are only 64 percent protective, that changes everything — including whether those vaccinated should test if exposed,” former Baltimore health commissioner Leana Wen said.
Two senior administration officials said the Biden administration does not plan to issue any new recommendations on mask-wearing in light of the Delta case spikes. Instead, officials said, the administration is looking to state and local communities to convince people to sign up for the shot. While the federal government is diverting resources across the country, the administration is also asking governors and mayors to help expand access to the vaccine by providing transport to the vaccination site and allowing people to take off work to get the shots.
Eric Topol, director of the Scripps Research Translational Institute, told POLITICO the increasing prevalence of the Delta variant means communities will need to redouble testing and contact tracing efforts.
“This is a really formidable variant, and we’re already seeing in multiple states that cases are going up — even as much as more than doubling in the recent two weeks — and hospitalizations are going up in those states,” Topol said.
The CDC spokesperson told POLITICO that it is “difficult” to predict the proportion of Covid-19 variants due to “reporting delays, the presence of multiple variants, and changing incidence.”
“CDC continues to evaluate approaches that can reliably predict these dynamics while making improvements to genomic surveillance to increase the number, representativeness, and timeliness of specimens,” the CDC spokesperson said.