Data updated by the CDC on Tuesday evening shows that the so-called delta variant, also known as B.1.617.2, is believed to be responsible for 57.6% of new confirmed cases nationwide from June 20 to June 3. July. The proportion was estimated at only 31.1% for the previous two weeks.
At the end of May, the delta variant accounted for about 3% of new cases in the United States, according to data from the CDC.
After initially being identified in India in October, the delta variant has since been reported in at least 104 countries around the world and is expected to soon be the dominant variant of the coronavirus circulating around the world, according to the World Health Organization. The variant was first detected in the United States in March and is now present in all 50 states.
“The delta variant is tearing the world apart at a breakneck pace, leading to yet another spike in cases and deaths,” WHO Director-General Tedros Adhanom Gebreyesus said on Monday at a COVID-19 press briefing.
Last week marked the fourth consecutive week in which the number of new confirmed cases of COVID-19 has increased around the world. Deaths are also on the rise again after 10 weeks of decline, according to Tedros, who noted that the WHO has received reports from all parts of the world on hospitals reaching capacity.
The WHO declared delta a “variant of concern” in May, and the CDC upgraded its classification of the strain in June from “variant of interest” to “variant of concern.” The WHO and CDC say the variants of concern have been shown to be both more infectious and more virulent than the other strains.
The delta variant has been shown to be particularly dangerous for those who are not or partially vaccinated against COVID-19, and preliminary data indicates that it may increase the risk of hospitalization.
However, current evidence suggests that the full dose of a COVID-19 vaccine is very effective in preventing hospitalizations and serious illness. Cases where a fully vaccinated individual becomes infected with COVID-19, known as breakthrough cases, are extremely rare. And while early laboratory studies indicated that vaccines appeared to produce significantly less anti-virus antibodies against some of the newer variants, the real-world experience tells a different story as researchers around the world learn that vaccines still work for the most part – even when these antibodies fail to show up in large numbers – thanks to other crucial parts of the body’s immune system.
Yet very little is known about the mutating virus, and it’s unclear how long immunity to vaccines will last and whether booster shots will be needed to maintain protection.
As delta and other highly transmissible variants cause ‘catastrophic waves’ of COVID-19 infections, WHO director-general urges vaccine manufacturers to prioritize delivery of doses to countries most poor with low vaccination rates rather than giving boosters to richer countries with relatively high coverage.
“The global vaccine supply gap is extremely uneven and inequitable,” Tedros said on Monday. “Some countries and regions are actually ordering millions of booster doses, before other countries have had supplies to immunize their health workers and the most vulnerable. “
Since the start of the pandemic, the United States has reported more than 33.9 million confirmed cases of COVID-19 and more than 607,000 deaths from the disease, according to data collected by Johns Hopkins University. The United States has recorded the highest death toll, while India has the highest total number of cases.
More than 184 million people in the United States have received at least one dose of a COVID-19 vaccine, including more than 159 million – 48.1% of the population – who are fully vaccinated, according to CDC data.
Brian Hartman, Arielle Mitropoulos and Dr Onyema Okolo of ABC News contributed to this report.