PROVIDENCE — Coronavirus levels in Rhode Island waste water rose at seven out of eight treatment plants in March, and they were up sharply in half of those sampling sites, according to the latest federal data.
The US Centers for Disease Control and Prevention launched a National Wastewater Surveillance System in September, describing it as an “early warning” system that would allow communities to act to prevent the spread of COVID-19.
But some public health advocates worry the early warning will be ignored at a time when Rhode Island is reporting a decrease in new COVID-19 cases and hospitalizations and people are eager to put the pandemic behind them.
“If this is an early indicator, we have to alert the community,” said Dr. Pablo Rodriguez, a public health advocate who is on the Rhode Island COVID-19 Equity Council. “Waste water has to tell us something. We can’t just ignore it.”
The latest waste water surveillance data shows that four treatment plants saw significant increases in concentrations of the virus between March 11 and 25. Two of those treatment plants were in Providence County, and two were in Bristol County.
Two other Providence County plants saw a moderate increase in concentrations, a Kent County site saw a lesser increase in concentrations, and one Providence County site saw a decrease, according to the federal data.
Meanwhile, coronavirus levels detected in Eastern Massachusetts waste water are ticking up slightly after bottoming out around the beginning of March, according to data from the Massachusetts Water Resources Authority. And the more-contagious Omicron subvariant BA.2 now accounts for more than half the new cases in New England.
But the latest state Department of Health data shows downward trends in COVID-19 cases and hospitalizations in Rhode Island.
On Thursday, the state reported 228 new cases, with a 4.1 percent positive rate. There were no new COVID-19-related deaths and 50 people were hospitalized with the virus. Also, all the weekly trend arrows for new cases, new hospitalizations, and percent positive rates were pointing downward.
Department of Health spokesman Joseph Wendelken said the waste water testing system is new and still in development.
“Local and national health officials are still working to understand how wastewater surveillance data should be interpreted,” he said. “CDC describes wastewater data as a potential early warning system that could be used alongside other datasets. However, we still need to learn more. In Rhode Island, we have not seen any recent, significant increases in cases, hospitalizations, or fatalities.”
Dr. Michael Fine, a former state Department of Health director who is now chief health strategist for Central Falls, R.I., said the waste water data is a clear sign that coronavirus is spreading in Rhode Island more than it had been in previous testing periods. And the timing is not good because holidays such as Easter, Passover, and Ramadan are coming up, he said.
“The only question is how much damage it is going to do,” Fine said.
Rodriguez said that while the number of new cases and hospitalizations are down, many people are now doing tests at home, so those results would not be reflected in the state data. And he said hospitalizations are a lagging indicator, meaning those numbers would go up only after the virus has begun to spread more widely.
If wastewater data is an early indicator, it indicates Rhode Island could see an increase in COVID-19 hospitalizations in the next two or three weeks, Rodriguez said.
Rodriguez said the federal government has provided no guidance about what to do about the wastewater data, and he acknowledged that everyone is tired of hearing about the pandemic and wants to return to normal life. But, he said, “We need to pay attention to the data even if we are sick of it. We are not done by any stretch of the imagination.”
Dr. Megan L. Ranney, a practicing emergency physician and academic dean of Brown University’s School of Public Health, said the waste water data is not enough, on its own, to indicate another COVID-19 surge is imminent.
“It’s not a panic mode yet,” she said. But it is something worth monitoring.
“To me, this is a really, really important thing to keep an eye on,” she said. “To me, this is a sign of: Let’s watch our case numbers a little more closely and think about what we would have to mobilize if there was another surge.”
Ranney said one challenge in analyzing the data is that it’s unclear if the waste water contains virus that passed through people’s bodies without triggering a positive test, causing symptoms, or sending people to the hospital.
And she said it’s unclear whether that virus would lead to more positive tests and hospitalizations at a time when more Rhode Islanders are vaccinated and the impact of the new variant remains unclear. As of Wednesday, 81.5 percent of Rhode Islanders were fully vaccinated, but just 39.7 percent had received boosters.
While the latest data reflects a relative increase, Rhode Island has not been testing its waste water long enough to know how significant that increase is compared to past periods when COVID-19 was surging here, Ranney said.
“The reality is today, even with the uptick seen in the wastewater monitoring, we are still at one of the lowest points in the pandemic in terms of cases,” she said.
And it’s no surprise that the virus levels in waste water would be rising now since so many people have stopped wearing face masks and taking other precautions, Ranney said.
In the next couple of weeks, the state will need to keep a close eye on the trends in new cases, hospitalizations, and visits to doctor’s offices and emergency rooms for upper respiratory illnesses, she said.
Meanwhile, Ranney said, “If you are not vaccinated, please get the vaccine, and if you are not boosted, get the booster, particularly if you are older than 50. This serves as a reminder that COVID is still here.”