London — Health experts warn that the rapid spread of the highly infectiousis a sign that the global race between vaccination and the could tip in favor of the latter, unless countries ramp up their immunization campaigns and practice caution. The variant first detected in India has been identified in at least 92 countries, , and is widely considered the most transmissible COVID-19 strain observed to date.
The Delta variant has an enhanced ability to prey on the vulnerable — particularly in places with low vaccination rates. Research conducted in the U.K., where the strain already accounts for 99% of new COVID-19 cases, suggests it's about 60% more transmissible than the Alpha variant, which previously dominated.
Delta may also be linked to a greater risk of hospitalization, and is somewhat more resistant to vaccines, particularly after just a single dose of the two-shot vaccines.
The strain's rapid domination in the U.K. — which is currently registering about 20,000 new cases daily, roughly 10-times the average in early May — has drawn tougher travel warnings from other countries and spurred the government to try and get all adults vaccinated as quickly as possible.
Outside an English soccer stadium, CBS News correspondent Roxana Saberi met young people who were lined up this week, waiting to roll up their sleeves.
"This is the first opportunity I've had to actually get vaccinated, and I'm looking forward to it," said one young man in the line.
The Delta variant has taken hold in Britain despite almost 62% of adults being fully vaccinated, a slightly higher rate than in the U.S. Most of the new cases are in younger people who've yet to have the two doses needed for maximum protection.
But in countries like Russia and Indonesia, where vaccination rates are much lower, the new strain is already being blamed for overwhelming hospitals and filling cemeteries.
In Australia, where tough border controls helped to keep cases in check over the last year and a half, officials just imposed a strict two-week lockdown on Sydney as infections mount.
CBS News' Elaine Cobbe in Paris reported on Tuesday that the Delta variant now accounts for one in five new COVID-19 cases in France — a similar proportion to that seen in the U.S. The French health minister said it would soon be the dominant variant in the country. France just emerged from a strict months-long lockdown and the overall situation continues to improve, but officials there, too, are watching with concern as the variant sweeps across neighboring Britain, where vaccination rates are higher.
In Germany, meanwhile, CBS News' Anna Noryskiewicz says the national government's health institute told state leaders this week that the Delta variant likely already made up about 50% of the country's total COVID-19 cases. But with overall infection rates still low, federal and state officials agreed not to tighten travel restrictions within the country.
Professor Sharon Peacock of Cambridge University leads the U.K.'s efforts to detect and map mutations of the coronavirus. She told CBS News that Delta, "will become a very dominant variant globally."
Asked if the U.S. could be heading for the same Delta takeover that hit Britain, she said there was "no reason why they wouldn't experience the same, similar thing to us."
Given the fact that the virus keeps mutating, Peacock told Saberi there was little doubt that "it's here for good... people will become infected. But we know how to treat people. We know how to prevent infection, and we then learn to live with it."
"The key for the U.S., as in the U.K., is vaccinate, vaccinate, vaccinate," stressed Peacock.
The English city of Bolton may provide a useful warning, and some hope. In early May, with less than a third of the city's adults fully vaccinated — a rate similar to some U.S. states — Delta sent infections soaring.
But since a "surge" door-to-door testing initiative to find cases and a decision to move vaccination sites into more deprived communities, COVID-19 cases have dropped in Bolton by almost half, according to the city's vaccine director, Doctor Helen Wall.
"For people who are managing vaccine programs, it's about understanding why people are hesitant, because hesitancy isn't just about not wanting it, it's about not being able to access it," Wall told CBS News.
Even vaccinated people can still become infected with COVID-19, but there's a far lower risk of hospitalization and death in people who've had the full recommended dosage.
British officials have pinned their hopes on the aggressive vaccination program in the U.K., and they say they don't anticipate having to change their plan to completely drop coronavirus restrictions on July 19.