World Health Organization Director-General Dr. Tedros Adhanom Ghebreyesus warned that achieving herd immunity is not a viable strategy for stemming the spread of coronavirus.

Less than 10% of the world's population has been infected with the virus, according to WHO, meaning that most individuals are still susceptible to the disease. Among those who have been exposed, there are many unknowns, including how high the immune response is after infection, how long it protects, and what the long-term impacts of infection are.

Worldwide COVID-19 cases continue to increase, with the highest rise occurring in the last four days, according to WHO. As of Monday, there had been 37.6 million infections worldwide according to Johns Hopkins University.

ABC News' Christine Theodorou contributed to this report.

Whistleblower Rick Bright, the federal vaccine expert who was ousted from the U.S. Department of Health and Human Services after he lodged a complaint against the Trump Administration earlier this year, said that the public should not trust the White House when it comes to information about the coronavirus, during an interview with ABC's The View on Monday.

"We need to hear directly from the scientists at the CDC, at the FDA and at the NIH," Bright said. "Public health guidelines have been disparaged and ignored," he added, referring to the White House.

"This is why we have 215,000 dead Americans today. This is why we have up to 50,000 new infections today. This is why we're going to have terrible winter if we don't do something now to turn around the rhetoric, tell people the truth."

An ABC News analysis of COVID-19 trends across all 50 U.S. states as well as Washington, D.C. and Puerto Rico found there were increases in newly confirmed cases over the past two weeks in 32 states as well as the nation's capital.

The analysis also found increases in the daily positivity rate of COVID-19 tests in 22 states plus D.C., increases in COVID-19 hospitalizations in 35 states and increases in daily COVID-19 death tolls in 13 states plus Puerto Rico.

The seven-day average of new cases in the United States is the highest it has been since Aug. 17.

Last week, 14 states reported their greatest single-day increases in the number of new COVID-19 cases, while 14 states hit a record number of current COVID-19 hospitalizations and two states recorded their highest single-day death tolls from the disease.

The trends were all analyzed from data collected and published by the COVID Tracking Project over the past two weeks, using the linear regression trend line of the seven-day moving average.

ABC News' Benjamin Bell, Brian Hartman, Soorin Kim and Arielle Mitropolous contributed to this report.

The Liverpool area will be placed on the highest tier of England's new COVID-19 alert system from Wednesday, with bars, pubs and gyms forced to close, British Prime Minister Boris Johnson announced.

Johnson outlined the country's new three-tier system of COVID-19 alert levels on Monday afternoon, while addressing lawmakers in the House of Commons. He said every area of England will be placed into one of the three tiers -- "medium," "high" and "very high."

The "medium" level, which the prime minister said will cover most of the country, will consist of national measures, including the "rule of six" -- a ban on any gathering of more than six people -- and a 10 p.m. curfew for hospitality venues.

The "high" level, Johnson said, will prevent all social mixing indoors between different households or support bubbles in an effort to reduce household-to-household transmission, with the "rule of six" still in effect for mixing outdoors.

"Most areas which are already subject to local restrictions will automatically move into the 'high' alert level," the prime minister told lawmakers.

The "very high" level will ban social mixing indoors and in private gardens, along with the closure of all bars, pubs, gyms, betting shops, casinos and leisure centers in these areas, according to Johnson. The Liverpool City Region, home to 1.5 million people, is the first area to enter the "very high" alert level.

"The 'very high' alert level will apply where transmission rates are rising most rapidly," Johnson said.

All retail outlets, schools and universities will remain open across England.

"This is not how we want to live our lives," the prime minister told lawmakers. "But this is the narrow path we have to tread between the social and economic trauma of a full lockdown and the massive human and indeed economic cost of an uncontained epidemic."

The new measures come as England saw its number of COVID-19 infections quadruple in the last three weeks. There are now more patients hospitalized with COVID-19 than when the country went into lockdown in late March, according to Johnson.

"I must warn the House, the weeks and months ahead will continue to be difficult and will test the mettle of this country," he said. "I have no doubt at all that together we will succeed."