During his first public briefing on America's coronavirus epidemic in months, President Trump on Tuesday warned that the epidemic likely "will get worse before it gets better," as U.S. officials reported the highest daily total of new deaths linked to the coronavirus that the country's seen since May.

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US new coronavirus cases surpass 3.9M, deaths near 142K

U.S. officials as of Wednesday morning had reported 3,910,300 total cases of the new coronavirus since the country's epidemic first began—up from 3,844,800 cases reported as of Tuesday morning.

Data from the New York Times shows that Puerto Rico; the U.S. Virgin Islands; Washington, D.C.; and 39 states saw their average daily numbers of newly reported coronavirus cases rise over the past 14 days: Alabama, Alaska, Arkansas, Colorado, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Mexico, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Vermont, Virginia, Washington, West Virginia, Wisconsin, and Wyoming.

California is on pace to surpass New York as the state that's reported the most coronavirus cases since America's epidemic began, the San Francisco Chronicle reports. California on March 19 was the first state to impose a statewide stay-at-home order and initially had seemed to be gaining control of its outbreak. But the state on May 8 began reopening nonessential businesses and relaxing social distancing and other measures intended to curb the virus' spread, and California in recent weeks has reported an average of about 9,000 new coronavirus cases each day—including a record high for the state of 11,554 new coronavirus cases in a single day on Monday.

Overall, however, the Times' data shows that the average daily numbers of newly reported coronavirus cases over the past two weeks remained mostly stable in California and seven other states: Connecticut, Hawaii, New Hampshire, New Jersey, New York, South Dakota, and Utah.

Arizona, Delaware, and Maine saw their average daily numbers of newly confirmed cases decrease over the past 14 days, according to the Times' data.

Meanwhile, although growth in America's national coronavirus-related death rate declined in June, data has shown that rate's been rising in recent weeks.

According to the Times', Puerto Rico; Washington, D.C.; and 24 states saw their average daily numbers of newly reported deaths linked to the coronavirus rise over the past 14 days: Alabama, Arizona, Arkansas, California, Florida, Georgia, Idaho, Iowa, Louisiana, Mississippi, Nebraska, Nevada, New Mexico, North Carolina, Ohio, Oklahoma, Oregon, South Carolina, South Dakota, Tennessee, Texas, Utah, Washington, and Wisconsin.

And on Tuesday, U.S. officials reported 1,029 new deaths linked to the novel coronavirus, marking the first day since May 29 that the country reported more than 1,000 new deaths linked to the virus in a single day, Politico reports.

Overall, officials as of Wednesday morning had reported about 142,031 U.S. deaths linked to the new coronavirus—up from about 140,904 deaths reported as of Tuesday morning.

Trump says America's coronavirus epidemic 'will get worse before it gets better'

Amid America's worsening coronavirus epidemic, Trump on Monday announced that the White House would resume holding briefings on the epidemic. The White House's coronavirus task force had held regular public briefings on the coronavirus during the beginning of America's epidemic, but Trump largely suspended those briefings in April.

Trump on Tuesday held the first of the resumed public briefings and had a notably different tone on the epidemic than he's had in other recent public remarks, the Wall Street Journal reports.

"Some areas of our country are doing very well. Others are doing less well," Trump said, describing outbreaks in some areas of the United States as "big fires." Further, Trump said, "It will probably, unfortunately, get worse before it gets better. Something I don't like saying about things, but that's the way it is."

To help contain the coronavirus' spread, Trump called on Americans to avoid crowded bars and wear face masks or coverings. "When you are not able to socially distance, wear a mask," he said. "Whether you like the mask or not, they have an impact, they'll have an effect and we'll need everything we can get."

Trump also promised a "relentless" effort to combat the virus, and said his administration is "in the process of developing" a national strategy to help further address the epidemic.

CDC estimates number of coronavirus infections could be up to 24 times higher than reported

Separately, CDC in a study published Tuesday in JAMA estimated that the number of U.S. coronavirus cases could be from six- to 24-times higher than the number of cases that have been reported in the country.

For the study, researchers examined the results of 16,025 serological tests—which can detect whether a person has antibodies to the novel coronavirus, indicating a previous infection—conducted between March 23 and May 12 at 10 sites in California, Connecticut, Florida, Louisiana, Minnesota, Missouri, New York, Pennsylvania, Utah, and Washington. The serological tests were conducted on blood samples from patients undergoing routine medical screenings, such as cholesterol tests, as opposed to seeking testing specifically for coronavirus antibodies or infection.

The researchers found that most of the samples tested negative for coronavirus antibodies. However, based on the number of tests that came back positive, the researchers estimated that the numbers of actual coronavirus infections were between six- to 24-times higher than the numbers of reported cases per site. In most regions, numbers of actual infections likely were 10-times higher than the reported number of cases, the researchers estimated.

Based on their findings, the researchers estimated that about 24% of New York City's population likely has antibodies to the novel coronavirus, which would be higher than any other region in the United States but lower than the 60% to 70% threshold needed to achieve herd immunity in a given area. And the researchers estimated that significantly lower portions of the populations in other areas have coronavirus antibodies. For example, they approximated that about 3.6% of Philadelphia residents and about 2.8% of Missouri residents have antibodies to the new coronavirus.

Jennifer Nuzzo, an epidemiologist at the John Hopkins Center for Health Security who was not involved in the study, said the findings suggest "[m]ost of us are likely still very vulnerable to this virus and we have a long way to go to control it." She added, "This study should put to bed any further argument that we should allow this virus to rip through our communities in order to achieve herd immunity."

Similarly, the study's authors in an editorial accompanying their research wrote that their findings "rebuk[e] the idea that current population-wide levels of acquired immunity (so-called herd immunity) will pose any substantial impediment to the continued propagation of [coronavirus] in the [United States], at least for now" (Luthi, Politico, 7/21; Baker, New York Times, 7/21; Stokols, Los Angeles Times, 7/21; Lucey/Restuccia, Wall Street Journal, 7/21; Budryk, The Hill, 7/21; Lim, Politico, 7/21; McGinley, Washington Post, 7/21; New York Times, 7/22; Dizikes/Koseff, San Francisco Chronicle, 7/21; Sidner/Kravarik, CNN, 7/22; Lin/Lee, Los Angeles Times, 7/21).