A man receives COVID-19 test at a mobile testing site in Times Square, New York, the United States, July 20, 2021. (Photo: Xinhua)

The new COVID-19 variants detected in New York City's sewage, which have developed antibody resistance that could cripple vaccines, should be further examined over whether they had caused infections among local residents, Chinese experts said on Monday, urging the US to take the issue seriously and be responsible to global public health.

A group of US researchers looking at human sewage for the concentration and mutated strains of the coronavirus have made a "startling discovery," reported The City on Thursday.

The findings carried out by the City University of New York, the New School and the University of Missouri said they have found four COVID-19 variants undetected before, and have developed certain degrees of antibody resistance, pointing to possible reductions in vaccine efficacy.

Chinese health experts believe that the key in analyzing the mutations' infection risks lies in its transmission ability and pathogenicity, but it would still be too soon to be alarmed. 

Yang Zhanqiu, a virologist at Wuhan University, told the Global Times on Monday that whether the mutated strains are something to be worried about will be determined by whether it has been spreading among people in the city, suggesting that the study should integrate data of local COVID-19 patients to see if the four new variants exist in any of them.

Tao Lina, a Shanghai-based vaccine expert, said on Monday that the study should compare the new mutations with the Delta variant that has been raging in the world and examine their similarities. But he also said it's too soon for the public to panic since most mutations are no more harmful than the original one. 

One "troubling possibility," according to the preprint study which has not been peer-reviewed, is that the new sewer mutations may come from infected dogs and rats, which further led to new generations of the virus and an outbreak in New York City's sewers.

"It further suggested that the coronavirus could not be completely wiped out, since it is likely to spread among animals and pass on to humans. Even more troublesome, the virus mutates itself in the animals' bodies and then goes on to infect people," Tao told the Global Times on Monday. 

Yang held a different view, saying that there has not been a precedent of animal-to-human transmission officially recorded in the coronavirus family, and the New York researchers' findings could still be the ones that only infect animals. 

The researchers said that their findings "earned a muted response" from the local government despite its potential implications that could weigh on epidemic control, The City reported. They were told they could continue their investigations, but the local Department of Environmental Protection offered no additional funding or support for their study.

However preliminary findings are significant, and the US must pay attention to the new variants, Yang noted, as it is a research project closely related to the public health problem across the world, and could have a great impact on coronavirus prevention, vaccine development and others. 

Engulfed by a new epidemic surge, the US hit a record of 101,171 daily infections on Friday, eclipsing the early February numbers. Dr. Anthony Fauci, the US top infectious disease expert, said on Sunday that the country will not lock down again to curb COVID-19 but warned "things are going to get worse," local media reports said.