NEW YORK - Experts are warning of the spread of a new strain of Omicron variant in the United States and potential health effects after infection, as major states in the country rushed to shed off COVID-19 restrictions amid a continuous decline in cases and hospitalization.

An Omicron subvariant, known as BA.2, which appears to spread 30 percent more easily, has made up 3.9 percent of all infections, up from 1.6 percent in the week ending Jan. 29, fueling worries the country may not return to normal as planned.

According to a report by National Public Radio, BA.2 is found to have quickly overtaken the original Omicron in South Africa and other countries and has even caused a second Omicron surge in Denmark.

Infectious disease experts cautioned the same could happen in the United States, raising fears that the spread "may be on track to rapidly accelerate in the near future," the report said.

Meanwhile, the risks of cardiovascular disease of all types increased substantially in the year following COVID-19 infection, according to a study published this month in Nature Medicine which looked into the health records of more than 153,000 US veterans.

Experts estimated there might be millions of new-onset cardiac cases related to the virus, plus a worsening of the disease for many already affected.

"We are expecting a tidal wave of cardiovascular events in the coming years from direct and indirect causes of COVID," The Washington Post reported, citing Donald M. Lloyd-Jones, president of the American Heart Association.

While New York State began to lift COVID-19 restrictions, not all residents favor the decision, The New York Times recently reported.

According to a new poll released on Tuesday by the Siena College Research Institute, 45 percent of registered voters said the state should have kept in place its rule of requiring masks or proof of full vaccination in indoor public areas, which was recently rescinded.

Regarding masks in schools, 58 percent agreed to wait to review virus data for early March before deciding whether to extend the state mandate.

"I wish the pandemic were over and it was safe to lift vaccine mandates, particularly in spaces where masks will be off for eating and drinking," said Sadiya Khan, an epidemiologist at Northwestern University Feinberg School of Medicine. "This seems like a move to promote normalcy without there really being normalcy."