WASHINGTON -- Fueled by the rapid spread of the highly transmissible Delta variant, a steady increase of COVID-19 cases, hospitalizations, and deaths has once again struck the United States, with surges seen especially in parts of the country where vaccination rates are low.

As of Tuesday, the total confirmed cases of the pandemic surpassed 34.6 million, while the country's death toll amounted to over 611,410, according to data from Johns Hopkins University.

Last week, 48 states have a seven-day average of new cases at least 10 percent higher than the week before. In 34 of those states, the rate of new cases increased by more than 50 percent, said the university.

"An increase in the number of cases will put more strain on healthcare resources and could lead to more hospitalizations and deaths," according to a weekly review conducted by the U.S. Centers for Disease Control and Prevention (CDC).

"THE PANDEMIC OF THE UNVACCINATED"

Health experts blame the recent balloning COVID-19 cases on the low vaccination rates and the accelerating Delta variant transmission, which have caused widespread worries that the rest of the year would be overshadowed by the exacerbating once-in-a-century epidemic in the United States.

The current COVID-19 surge in the country will steadily speed up through this summer and fall, reaching a peak in mid-October and with daily deaths more than triple what they are now, said an article published by the U.S. non-profit media organization National Public Radio (NPR).

The United States is facing "the pandemic of the unvaccinated," for at least 99 percent of those who died of COVID-19 in the nation in the last six months had not been vaccinated, Rochelle Walensky, director of the CDC, has told media.

Los Angeles County officials said about 98 percent of those hospitalized in the last six months were unvaccinated people, adding Delta is a "game changer" as cases now rise among the vaccinated.

Likewise, up to 94 percent of COVID-19 hospital patients and 96 percent of Alabamians who have died of COVID-19 since April were not vaccinated, according to the Alabama Department of Public Health.

Among American adults who have not yet received a vaccine, 35 percent say they probably will not, and 45 percent say they definitely will not, according to a poll from The Associated Press-NORC Center for Public Affairs Research.

What's more, 64 percent of unvaccinated Americans have little to no confidence the shots are effective against variants, including the Delta variant that officials say is responsible for 83 percent of new cases in the United States, the poll added.

The reasons why Americans refuse to get inoculated include "a belief that the virus is not that bad, the hope that rural lifestyles make catching COVID-19 less likely and general distrust of government experts," according to a recent report by CNN.

MULLING MASK WEARING

Slow vaccinations across the United States have ignited debate over mandated mask wearing and vaccinations. Experts said with the highly contagious Delta variant spreading, particularly among unvaccinated Americans, it may be time for much of the country to put masks back on.

The CDC is weighing revising its COVID-19 guidelines to recommend that even fully vaccinated people wear masks in public, said Anthony Fauci, White House chief medical advisor, on Sunday.

Fauci told CNN that he has taken part in conversations about altering the guidelines, something he described as being "under active consideration."

He noted that some local areas where infection rates are surging are already urging individuals to wear masks in public regardless of their vaccination status.

In a recent Tweet, former U.S. Surgeon General Jerome Adams also said data suggested that the CDC should advise mask wearing "in areas with (rising) cases and positivity until we see numbers going back down again."

U.S. Treasury Secretary Janet Yellen last week also called on the country to reimpose government-mandated capacity restrictions on businesses, such as bars and restaurants.

OPPOSING POLITICIZATION OF ORIGIN TRACING

Apart from calls for regular mask wearing in the United States, health professionals and experts urged the White House to shift their anti-pandemic focus onto scientific measures such as establishing "much better" early response systems for disease outbreaks, rather than trying hard to politicize the virus origin tracing and scapegoat others.

Fauci has repeatedly cited "a scientific paper from July that argued in favor of zoonosis and largely dismissed the lab leak hypothesis."

In the paper titled "The Origins of SARS-CoV-2: A Critical Review," a group of 20 internationally renowned virologists and evolutionary biologists from all over the world note that theories about a lab leak are almost all based on coincidence, not hard evidence.

"I mean ... although we keep an open mind that it's possible that it could be, as they say, a lab leak, that the most likely explanation is a natural evolution from an animal reservoir to a human," Fauci told local media.

Besides, U.S. Central Intelligence Agency Director William Burns has said there may be no definite conclusion about the origins of COVID-19, according to U.S. media.

"The honest answer today is that we cannot offer a definitive conclusion about whether this originated in a lab accident or whether it originated in a natural transmission from infected animals to human beings," Burns said when asked whether the virus was created in China's Wuhan lab during a recent interview with NPR.

The real issue about COVID-19 origins is how to prevent future pandemics based on international cooperation, instead of blaming or acquitting some countries, said Jeffrey D. Sachs, director of the Center for Sustainable Development at Columbia University and president of the UN Sustainable Development Solutions Network.

"The question about origins is not about one government or another, much less a geopolitical issue or a matter of blaming China and exonerating the U.S.," Sachs wrote in an opinion article published in Project Syndicate in late June.

"Because natural zoonotic events are inevitable, we must establish much better global surveillance and warning systems, and of course early response systems when outbreaks occur," he said.