Is COVID back in NYC? Wastewater surveillance shows virus is rising.

New Yorkers who've noticed more sniffles and coughs during their subway commutes aren’t imagining things. Wastewater monitoring is showing early signs of a coronavirus rebound in New York City and some surrounding suburbs.

All 14 wastewater treatment plants across NYC are reporting high concentrations of SARS-CoV-2 coronavirus, according to the dashboard run by NYS Wastewater Surveillance Network. A “high” ranking translates to at least 50 or more COVID cases per 100,000 people.

The dashboard also gives a readout on two-week trends. The current rise dates back to late April for most sewersheds in the city, though ones covering Brooklyn, Staten Island, Queens and part of the Bronx recorded the starkest upturn over recent weeks. Wastewater from Yonkers, New Rochelle and parts of Rockland county are also trending upward with their coronavirus concentrations.

Wastewater sites share data with the state dashboard on a regular basis, and as of Wednesday, the latest tranche of NYC recordings dates to May 21 — meaning the increase was underway ahead of Memorial Day gatherings. The state health department told Gothamist that test positivity — the percentage of diagnostic tests showing an infection — has also risen slightly, though experts said this measure is harder to trust now that laboratory testing is less common.

The New York City health commissioner confirmed the wastewater uptick, but he and public health researchers said it’s too early to tell if the rise indicates the start of a full blown wave. The change could just be a blip caused by more people hanging out as the weather improves or due to a new version of omicron finding occasional places to thrive.

“We look at wastewater data really over time,” said NYC health commissioner Dr. Ashwin Vasan. “We need to look at it a little bit over longer time periods to draw any important inference.”

The wastewater trend is noteworthy because similar signs have not appeared yet among confirmed cases — the classic way that people have followed COVID-19 patterns for the past three years. This metric depends on PCR testing, which labs and hospitals are no longer required to do, given rollbacks in recent months and the conclusion of COVID public health emergency in early May.

Daily, routine testing of staff and visitors had meant hospitals could serve as beacons for changes in community levels of the coronavirus. But hospitals statewide are no longer required to conduct SARS-CoV-2 testing except in outbreak situations, and the state also no longer requires hospitals to test people without symptoms. It’s mostly up to individual facilities to decide if and when they want to test

“Hospitals have the discretion to continue to conduct admission/discharge testing for vulnerable populations,” said state health department spokesperson Erin Clary. “Nursing homes have the discretion to require testing in certain situations.”

Ahead of the public health emergency’s final days in early May, more than 10,000 people were still taking COVID tests daily in New York City. This seven-day average has now dropped below 4,000.

The consequences are that familiar metrics like test positivity and case rates may take longer to reveal community outbreaks if and when a surge arrives, said Dr. Bruce Y. Lee, a professor at the CUNY School of Public Health and executive director of the research group PHICOR.

“The number of reported cases and testing results – we have to take with a huge grain of salt because it probably does not represent anywhere close to all of the cases that are really occurring,” Lee said. “It might even represent a very small fraction, and we have to remember that the variation in testing from week to week will also affect those numbers as well.”

He added that wastewater only gives a general idea on coronavirus spread in a community and does not offer the same neighborhood-by-neighborhood resolution as lab testing. A single wastewater plant can cover anywhere from 130,000 people (Rockaway) to more than 1.1 million (Newtown Creek) in New York City.

Hospitalizations and deaths still provide faithful readouts given those are still reported to public health departments, but those signs can take weeks to show up once a surge is already underway. Clary, from the state health department, said New York is also reporting a slight increase in COVID hospitalizations, while cases and overall testing remain down.

She added that the state agency continues to record COVID rates from hospitals and nursing homes that decide to submit results. It is also monitoring wastewater data and reports of COVID-like symptoms collected by emergency departments, as part of what’s known as syndromic surveillance.

“The Department plans to offer public online data dashboards for both in the near future,” Clary said. The Centers for Disease Control and Prevention told Gothamist that the Northeast is also experiencing an increase in four other common respiratory germs – human parainfluenza viruses (HPIV), human metapneumovirus, respiratory adenovirus and the CoVNL63 coronavirus — but that their activity remains within the range expected for this time of year. New York state has recorded about 2,400 COVID deaths this year, about a third of which happened in the city, according to CDC data.

When it comes to SAR-CoV-2, “we would expect New York City to potentially go first,” said Dr. David Larsen, a Syracuse University professor who runs the New York state wastewater surveillance network dashboard. He said he would want to see more data on the surrounding suburbs before confirming an upward trend there. In mid-March, the city switched to a more sensitive method for detecting coronavirus in wastewater, but that switch isn’t responsible for the new uptick, Larsen said.

Biobot, a wastewater analytics company that collaborates with the CDC, is also reporting more coronavirus activity in Nassau County in recent weeks that’s trending toward surpassing the national average.

“We'll have to continue to monitor the data to see if anything changes this year,” said Hannah Totte, an epidemiologist at Biobot, which also tracks mpox and is expanding to follow norovirus.

Totte and Vasan said that it wouldn’t be too surprising to see a late spring rebound, as that’s happened in past years. Lee added that COVID-19 is gradually confining itself to autumn and winter months, but it hasn’t become seasonal quite yet. At the moment, wastewater coronavirus rates are still lower than peak periods seen during this past winter’s surge.

Vasan said the playbook hasn’t changed for responding to COVID. His recommendations are three-fold. At-risk groups and their loved ones should be mindful if signs of transmission continue to rise and consider precautions. If cases or hospitalizations reach high levels, mask-wearing indoors is recommended. Also, get vaccinated.

Less than 20% of New York City is up to date on their shots, meaning they’ve taken a bivalent dose that protects against omicron.

“It's less about worry and more about preparation. COVID is here. It's not going anywhere. We're living with it,” Vasan said. “We have shown that we can start to regain a sense of normalcy and rebuild our city even with COVID still circulating.”