TOKYO -- Japan on Monday officially downgraded the legal status of COVID-19 to the same category of seasonal influenza and relaxed other COVID-19 measures previously in place.

The downgrading of the virus means it will no longer be in a special category equivalent to or stricter than Class 2, but is now categorized among Class 5 diseases like seasonal influenza.

If there is in future a spike in cases of COVID-19 infections, under the new lowered categorization, a state of emergency will not be declared and people and businesses are allowed to make decisions by themselves on antivirus measures.

As for quarantine guidelines following infection, the government here had previously recommended that those testing positive for COVID-19 isolate for a period of seven days and those who had been in close contact with an infected person quarantine for five days.

The government has removed these guidelines, although some advisories remain in place for students and others, including nursing care providers.

Prior to this, on March 13, the wearing of face masks became a decision left up to each individual.

COVID-19 vaccinations will continue to be free through this fiscal year, although residents of Japan will have to pick up the tab for outpatient care or hospitalization for COVID-19-related care and treatment.

Expensive hospital treatments may be eligible for subsidies until September this year, however.

In addition, under the government's eased regulations, patients admitted to hospitals with COVID-19 will no longer be treated at designated facilities, but at regular hospitals.

The downgrading of the virus and easing of some related restrictions has led to some concerns from experts at medical institutions, however.

Shoji Yokobori, who heads the critical care center at the Nippon Medical School Hospital, said he is concerned that the number of infected patients could surge or patients could become severely ill under a new variant of COVID-19.

In addition, Yokobori said fears were rife that infections could continue to spread in homes for seniors and that when the cost of receiving treatment for the virus is not fully covered by the government, patients will stop seeing doctors.

Tetsuya Matsumoto, a professor at the International University of Health and Welfare also voiced his concerns, saying that henceforth it may be difficult to monitor the number of cases in Japan should there be a further wave of infections.

"The medical system, which appears to be improving, may not actually have the capacity to sufficiently respond. The challenge is how to steadily increase the number of medical institutions that can receive patients," Matsumoto said.

Under the auspices of the health ministry's advisory panel, a group of experts warned earlier last month that a ninth wave of infections could hit Japan.

Japan's health minister Katsunobu Kato has previously highlighted an uptick in cases in Japan of a new subvariant of COVID-19.