About a month ago, the delta coronavirus variant first identified in India made up about 6% of genetically sequenced COVID-19 cases in the U.S.
Now, new national data predicts the highly contagious variant will make up about 52% of analyzed coronavirus cases in the country by the end of the two-week period ending July 3, officially deranking the previously dominant alpha variant first found in the U.K.
That’s a jump from about 30% in the two-week period ending June 19, according to data from the Centers for Disease Control and Prevention. Because of reporting delays and multiple interfering variants, federal health officials say the latest estimates mirror case and hospitalization trends in different regions, particularly those with low vaccination rates.
In some states, such as Iowa, Kansas, Missouri and Nebraska, the delta variant comprises more than 80% of sequenced coronavirus cases there.
The most recent evidence shows the variant is about 60% more contagious than the alpha variant; it’s been causing major outbreaks in other parts of the world with low vaccination rates, sending some countries, such as New Zealand, Bangladesh and Australia, back into lockdown.
“If ever there was a reason to get vaccinated, this is it,” White House chief medical adviser Dr. Anthony Fauci told CNN on Tuesday, adding that the delta variant is not only more contagious, but it can also cause more severe disease.
So, what does the delta variant mean for the unvaccinated?
About 99.5% of coronavirus deaths over the last six months have occurred in unvaccinated people, CDC Director Dr. Rochelle Walensky said last week during a White House COVID-19 briefing. She called the current “suffering and loss … entirely avoidable.”
An Associated Press review of government data from May also found that breakthrough infections, or those that occur in fully vaccinated people two or more weeks after receiving all their shots, made up less than 1,200 of the more than 107,000 COVID-19 hospitalizations — about 1.1%.
And of the more than 18,000 coronavirus deaths in May, only about 150 were in fully vaccinated people, or about 0.8% (five deaths per day on average).
“Right now we have two Americas: the vaccinated and the unvaccinated America,” Dr. Paul Offit, an infectious disease specialist at Children’s Hospital of Philadelphia, told NPR. “We’re feeling pretty good right now because it’s the summer. But come winter, if we still have a significant percentage of the population that is unvaccinated, we’re going to see this virus surge again.”
How well do COVID-19 vaccines work against the delta variant?
The good news is that the currently available COVID-19 vaccines offer adequate protection against the delta variant and other variants of concern spreading in the U.S.
A study from Public Health England found that three weeks after one dose, the Pfizer-BioNTech vaccine was 33% effective against symptomatic COVID-19 caused by the delta variant. Two weeks following the second dose, which is recommended for full protection, it was 88% effective.
And new results from a laboratory study showed the Moderna COVID-19 vaccine appears effective against the delta variant, with just a “modest reduction” in antibody levels compared to the original strain.
The Johnson & Johnson COVID-19 vaccine also spurred antibody activity against the delta variant, the company announced Thursday, and “at an even higher level” compared to that of the beta variant first identified in South Africa. In all, it was 85% effective against severe/critical disease and protected against hospitalization and death.
However, data from Israel shows the Pfizer vaccine’s effectiveness has dropped to 64% in preventing infection and symptomatic illness as the country deals with the delta variant, which has become the dominant version of the virus there.
Still, the shot remains 93% effective against serious COVID-19 and hospitalization.
While the COVID-19 vaccines in the U.S. are effective enough to protect against severe disease and death caused by the delta variant, experts say the more the coronavirus hops from one person to the next, the more chances it has to mutate into a version that could one day evade the shots’ defenses.
The World Health Organization even suggested fully vaccinated people still wear face masks whenever possible, citing the delta variant’s increased transmissibility and risk of serious COVID-19. It has been found in at least 98 countries as of July 2.
The advice arrived more than a month after the CDC gave the green light for fully vaccinated Americans to ditch their masks in most scenarios. But in response to the WHO’s advice, Walensky said “if you are vaccinated, you are safe from the variants that are circulating.”
The CDC said it will leave decisions on face mask requirements up to individual states; however many health experts outside either agency seem to agree with erring on the side of caution.