The World Health Organization (W.H.O.) warned on Monday that new, and estimated to be more contagious variants of the coronavirus could further complicate the global pandemic and may lead to more infections and hospitalizations if their spread is not immediately suppressed.

Dr. Tedros Adhanom Ghebreyesus, director-general of the global health agency, stated during a press briefing at W.H.O. headquarters in Geneva that the agency was alerted to a third coronavirus mutation discovered in Japan over the weekend, adding to the growing list of variants first found in the United Kingdom and South Africa.

Japan's National Institute of Infectious Diseases (N.I.I.D.) announced on Sunday that it has discovered the first four cases of a new COVID strain that was detected in travellers arriving in the country from Brazil on Jan.6. While researchers at the N.I.I.D. do not know the new variant's genetic make-up at this time, they have observed that the variant shares some of the same mutations found in the U.K. and South Africa strains.

The COVID strain discovered in Japan belongs to the B.1.1.248 variant and has 12 mutations in its spike protein, according to N.I.I.D. researchers.

While it is common for viruses to mutate overtime, it is difficult to know how widespread new variants are throughout a population. Currently, the three new COVID strains appear to be more infectious than prior variants of the virus, but do not seem to make infection more severe.

Tedros warned that the new COVID mutations "can drive a surge of cases and hospitalizations, which is highly problematic for health workers and hospitals already close to breaking point. This is especially true where public health and social measures have already broken down."

The only way to prevent the new COVID mutations from accelerating their spread through a population is to limit the virus' transmission through public health guidance like proper face coverings, physical distaning and hand washing, Tedros added.

In the places where new variants have spread, their outbreaks have rapidly worsened.

The United Kingdom reported on Monday that one in 20 people throughout the greater London area are now infected with the coronavirus, which is threatening the integrity of the country's National Health System as hospitalizations rise at an alarming rate, Reuters reports.

U.K. Health Minister Matt Hancock stated that there are now more than 32,000 patients hospitalized due to their COVID infections, according to Reuters, up from the roughly 18,000 during the nation's first wave back in April.

"Anybody who is not shocked by the number of people in hospital who are seriously ill at the moment and who are dying over the course of this pandemic, I think, has now understood this at all. This is an appalling situation," Chris Whitty, U.K. chief medical adviser, told BBC TV, quoted by Reuters.

In California--which is one of the few U.S. states to identify infections from the U.K. variant and the heart of the nation's surging outbreak--one person dies every 8 minutes from their coronavirus infection in Los Angeles County, Public Health Director Barbara Ferrer stated during a press briefing on Monday, according to CNBC. The county has reported over 1,500 COVID-related deaths in the past seven days.

According to the L.A. County Department of Public Health, deaths in the area have increased by more than 1,000% since the start of the virus' surge in early November, with 10 people every minute, on average, testing positive for COVID-19. More concerningly, at least 10-12% of infected individuals are hospitalized at some point, with more than 1% of infections being fatal.

"Now is the time to stay home as much as possible," Ferrer said, quoted by CNBC. "Now is the time to avoid, as much as possible, contact with others that aren't in your household."