Coronavirus was detected in Massachusetts sewage at higher levels than expected, suggesting there are many more undiagnosed patients than previously known, according to a new study.

Researchers from biotech startup Biobot Analytics collected samples from a wastewater facility for an unnamed metropolitan area in late March, according to a report Tuesday on medRxiv.

Eric Alm, one of the authors of the study, which has not yet been peer reviewed, stressed that the public is not at risk of contracting the virus from particles in the wastewater, but they may have the potential to indicate how widespread the virus has become, Newsweek reported.

“Even if those viral particles are no longer active or capable of infecting humans, they may still carry genetic material that can be detected using an approach called PCR (polymerase chain reaction), which amplifies the genetic signal many orders of magnitude, creating billions of copies of the genome for each starting virus,” Alm told the outlet.

The researchers, along with a team from Massachusetts Institute of Technology, Harvard, and Brigham and Women’s Hospital, analyzed the samples and found the number of coronavirus particles equated with 2,300 people being infected with the virus.

But at the time of tests, there were only 446 confirmed cases in the region, according to the study.

“It was interesting that our estimation was definitely higher than the number of confirmed cases in the area,” said Mariana Matus, CEO and co-founder of Biobot, according to Stat News.

The researchers shared their findings with local health officials, who said it was plausible there were hundreds of undetected cases.

“They could believe that [our] numbers could be correct and not out of the realm of possibility,” Matus told the outlet.