Should the delta variant change the US pandemic playbook?

A more contagious variant of the coronavirus, known as Delta, has spread to more than 80 countries around the world and now accounts for at least 20 percent of COVID-19 cases in the United States.

First identified in India, Delta is believed to be between 40 and 60 percent more transmissible than the Alpha variant that was first identified in the United Kingdom, which itself was substantially more contagious than the original coronavirus strain that started the global pandemic.

The Delta variant has fueled outbreaks around the globe and forced a growing number of countries to impose new restrictions to reduce its spread. Even nations that had been lauded as models for pandemic containment and vaccine distribution - such as South Korea, Australia and Israel have throttled back reopening plans in response to the variant. Delta is believed to be a factor in major surges reported in developing countries in Africa, Asia and South .

Delta is expected to become the dominant strain in the U.S. in the coming weeks and poses the "greatest threat" to America's efforts to eliminate COVID19, according to Dr. Anthony Fauci, the nation's top infectious disease expert. Despite these concerns and the aggressive response taken in some of America's peer countries, Fauci and other top government health officials say the variant probably won't dramatically change the course of the U.S. virus response. "Where people have gotten the two shots, the Delta variant is highly unlikely to result in anything," President Biden said in mid-June.

The key factor that distinguishes the U.S. from other nations that have responded aggressively to the variant, Fauci said, is the relatively high percentage of Americans who have been vaccinated against COVID-19.

There's evidence that fully vaccinated people enjoy similar levels of protection against Delta as they do from other variants, though those who have only had one dose appear to face greater risk. Administration officials argue that the best way to stamp out Delta is to stay the course on the campaign to get as many Americans vaccinated as possible, rather than spend time and resources on other, less effective mitigation efforts. Some experts, however, say the U.S. should amend its approach in response to the Delta variant.

Though more lockdowns seem far-fetched, some have called for the Centers for Disease Control and

Prevention to reverse its guidance that vaccinated people can go maskless indoors - at least until there's clear evidence that they can't pass the Delta variant along to the unvaccinated. Others say the Biden administration should do more to inform the public of the dangers posed by Delta.

While the U.S. is ahead of most countries on vaccinations, only half of the total population is fully protected, which could leave ample room for Delta to cause severe outbreaks - especially in communities with low vaccination rates.

Global health experts argue that the Delta variant should serve as a wake-up call for rich nations like the U.S. about the dangers of letting the virus run rampant in the developing world. Beyond the moral imperative of preventing unnecessary death among the world's poor, wealthy countries risk allowing a vaccine-resistant form of the virus to evolve unless they dramatically ramp up foreign aid efforts, they argue.

Areas of the country with low vaccination rates and high summer temperatures that force people to congregate indoors could serve as a test case for the dangers of the Delta variant, scientists say. "Watch the South in the summer," one epidemiologist told the Atlantic. "That'll give us a flavor of what we're likely to see in the fall and winter."

"While no strain yet has proven too much for vaccines to resist, it would be best to avoid that possibility altogether. If nothing else, it would be nice to silence liberal talking heads who incessantly drone on about how each new variant will definitely be the one that brings civilization to its knees." - Robert Schmad, Washington Examiner

"If, God forbid, there was a new variant that our existing vaccines proved helpless against, then reinstating mask-wearing for vaccinated people would make sense.

But that's not the case. So far, the vaccines are working against the Delta variant." Jim Geraghty, National Review. "The virus is disproportionately dangerous to the elderly. People have assessed their risk level and acted accordingly. Even if cases go up, this data suggests hospitalizations and deaths won't skyrocket like they did last summer." - Victor Joecks, Las Vegas Review-Journal.

"The CDC needs to act quickly, without waiting, to follow the WHO guidelines and ask everyone to put the masks back on so we can stay open, protect folks, and keep the economy going." - Public health expert Shad Marvasti to Yahoo Finance.