WASHINGTON — Just three weeks ago, Great Britain celebrated the success of its vaccination campaign by lifting several coronavirus-related restrictions. “Goodbye, lockdown,” said one headline. But since then, a more transmissible new strain of the coronavirus has taken hold, with plans to fully reopen the country on June 21.
Public health officials in the United States are now grappling with the possibility that a similar regression could happen here and, like in the UK, jeopardize the end of the pandemic, which many saw for this summer.
The powerful new version, known as Delta or B.1.617, emerged in India during that country’s recent coronavirus surge. According to British Health Secretary Matt Hancock, it is about 40 percent more transmissible than the original strain, or wild type, which first emerged in 2019. While many coronavirus variants have emerged since the start of the pandemic, epidemiologists worry that the mutation could cause a strain that survives vaccines.
According to genomic sequencing studies, the delta variant accounts for only 6 percent of cases in the United States. But that could change rapidly, President Biden’s top public health adviser Dr. Anthony Fauci warned during Tuesday’s briefing of the White House pandemic response team.
“We cannot let this happen in the United States,” Fauci said, describing the scenario in the UK as a “powerful argument” for vaccination. Biden is aiming to have 70 percent of American adults vaccinated by the weekend of July 4. Although the nation has now passed 300 million doses of the administered coronavirus vaccine, efforts have recently slowed.
The emergence of the delta variant presents a new challenge because, as immunologist Eleanor Riley of the University of Edinburgh told the Financial Times, vaccines “offer somewhat less protection against infection with the delta variant.” Even fully vaccinated people appear to develop fewer neutralizing antibodies against the delta strain than other types.
Fauci also said at Tuesday’s briefing that the new variant may be “associated with increased disease severity” compared to the wild type of coronavirus.
Fauci said Tuesday that people who received their first doses of only two-dose vaccines from Pfizer and AstraZeneca appear to be particularly vulnerable to the delta version. (The AstraZeneca vaccine has been widely used in Europe, but is not being administered in the United States; in contrast, the Moderna vaccine is popular in the United States, but not in the United Kingdom.) While both vaccines are around 50 percent were effective. Three weeks after the first dose of the original SARS-CoV-2 strain, they were only 33 percent effective against the delta strain.
Two weeks after the second dose, their effectiveness reached 88 percent for Pfizer and 60 percent for AstraZeneca, with only a slight decrease in effectiveness compared to the original coronavirus strain.
According to government figures, seventy percent, or 40 million, of the British population over the age of 18 have had a single bullet; 28 million have taken a second shot, accounting for 54 percent of the population.
The United States is in a similar situation, according to the Centers for Disease Control and Prevention, having fully vaccinated 53 percent of its adult population; 64 percent are partially vaccinated.
During Tuesday’s briefing, Fauci noted that peak transmission of the virus was in the UK in the 12 to 20 age group. Teenagers in the United States were made eligible for the vaccine last month. In the UK, however, vaccination for young people has been quite slow.
England, where 56.3 million of the UK’s 66.8 million residents live, began immunizing 25- to 29-year-olds only this week.
Asked what the Biden administration was doing to blunt the effects of the Delta tension, a White House official drew a flurry of encouragement and outreach efforts announced by the president last week.