President Joe Biden warned Friday that Delta, a coronavirus variant first discovered in India, poses an increased threat to unvaccinated Americans.
“It is a variant that is more easily transmissible, potentially deadlier, and particularly dangerous for young people,” Biden said at a White House news conference.
His remarks came just hours after Rochelle Walensky, director of the Centers for Disease Control and Prevention, told “Good Morning America” that Delta would likely become the dominant strain in the US in the coming months. (Some experts have even suggested that might even happen within weeks.)
Delta represents just 10% of US COVID-19 cases so far, but it already makes up around 90% of cases in the UK, according to a study from Imperial College London that’s still awaiting peer review. The researchers also found that COVID-19 cases in the UK are doubling every 11 days, most likely as a result of the fast-spreading variant.
Research from Public Health England suggests that Delta is associated with a 60% increased risk of household coronavirus transmission compared to Alpha — the variant discovered in the UK. Alpha is already around 50% more transmissible than the original coronavirus strain, according to the CDC.
Young people may be particularly susceptible to a Delta infection for two reasons: They’re more likely to be socially active and less likely to be vaccinated than older adults.
In the US, fewer adults under 50 have gotten vaccinated than adults ages 50 and older. The Imperial College London researchers also found that coronavirus infections in the UK are two-and-a-half times more prevalent among people ages 5 to 49 than among those ages 50 and older. Most young people who recently got infected were unvaccinated, according to the study.
Experts increasingly worry that young people will be less protected against severe disease caused by a Delta infection: Researchers in Scotland found that getting infected with Delta doubles the risk of hospital admission relative to Alpha.
Emerging research also suggests that a single vaccine dose doesn’t hold up as well against Delta compared to other coronavirus strains. Recent Public Health England analyses found that two doses of Pfizer’s vaccine were 88% effective at preventing symptomatic COVID-19 from Delta cases, while a single shot was just 33% effective by the same standard.
“Please, please if you have one shot, get the second shot as soon as you can,” Biden said on Friday.
So far, less than 45% of Americans are fully vaccinated, while 53% have received at least one dose. US vaccination rates have also fallen dramatically in the last two months, from a weekly average of nearly 3.4 million doses per day in mid-April to fewer than 780,000 doses per day on Thursday.
The more vaccination rates continue to drop, the more opportunities there are for Delta to spread — and therefore keep replicating and mutating.
“The worst-case scenario is if Delta mutates into something completely different, a completely different animal, and then our current vaccines are even less effective or ineffective,” Vivek Cherian, an internal medicine physician in Baltimore, recently told Insider.
Still, Biden said the US likely wouldn’t return to lockdowns because so many people have been vaccinated already.