Aug. 26, 2024 – Instead of peaking and retreating, this summer’s unusually prolonged COVID-19 wave is now firmly on course to collide with back-to-school season. That means more people spending time in close quarters indoors, like classrooms, and college students traveling back to campuses. It’s a recipe for an unpredictable period in the pandemic’s fifth year, and infectious disease experts are beginning to worry.
At the start of the summer, many hoped COVID would continue its trend toward joining the ranks of seasonal respiratory illnesses.
“This is a more substantial summer bump than we would have anticipated,” said William Schaffner, MD, an infectious diseases and preventive medicine expert at Vanderbilt University Medical Center in Tennessee. “I am concerned that this COVID wave may not be much of a wave. It may be a surge and it may continue. There’s been a lot of COVID out there, and for the first time, I’m just a little nervous about how much of a dip we’re going to get before it goes up again in the wintertime.”
A small Texas school district canceled classes Wednesday to conduct a deep clean due to widespread COVID. The Calvert Independent School District operates a single school that typically enrolls fewer than 150 students in prekindergarten through 12th grade. Their first day of school was Aug. 6.
Meanwhile, some college student health centers, such as the University of Arizona's, are telling students seeking COVID vaccines to get them at local pharmacies, at least until updated ones are stocked. From preschool to graduate school, the advice is to maximize prevention efforts like staying up to date on vaccines, practicing good hygiene like frequent hand-washing, and, if someone has symptoms of a respiratory illness, following CDC guidance to help prevent spreading a virus.
In K-12 school districts, many ask that parents let their child’s school know if hey test positive for COVID. It’s best to check what your district’s policy is about returning to school after an illness, and a health care provider can also advise parents and caregivers on when a child is well enough to return to class. Generally, feeling better and being fever-free for 24 hours, plus being able to eat, drink, and have normal bathroom visits, are signs that daily activities can resume.
A COVID-filled back-to-school season is somewhat of a surprise. At the start of the summer, many hoped COVID would continue its trend toward joining the ranks of seasonal respiratory illnesses. But ever-improving forecasting, which is increasingly being informed by the contents of the nation’s sewers, points toward not a summer COVID wave, but now a months-long surge.
Wastewater: Your Ultra-Local COVID Report
Wastewater detections of SARS-CoV-2, the virus that causes COVID, are now being used more to predict hospital caseloads and community impacts. In New York state, for example, statistical models using wastewater data can accurately forecast hospitalization rates 10 days in advance.
The CDC’s latest wastewater monitoring report said COVID detections nationwide were “very high,” its highest label. Overall, 44 states reported either “high” or “very high” levels, with chart-topping readings reported in the Western U.S.
The reason wastewater sampling can help forecast increased COVID activity is because people “shed” signs of the virus as soon as they become infected, and that shows up in wastewater even before people have symptoms. It’s also information that can be collected without the need for people to get tested themselves, which many either currently do at home or not at all.
For the average person who wants to understand local COVID trends using wastewater data, the first step is to find out if any wastewater samples are being taken from nearby. The CDC suggests checking your state, county, or city health department webpage to see whether they publish wastewater monitoring reports and site locations.
“I don’t think looking at national data is going to tell me something that’s going to be useful for how I’m going to interact in my current life and tell me if I should be worried about COVID right now,” said Katelyn Leisman, PhD, who works on the state of Illinois’s wastewater surveillance project and also is a research assistant professor in the Engineering Sciences and Applied Mathematics Department at Northwestern University in Evanston, IL.
But just like for hospital systems that use wastewater as a bellwether, increases in one area of the country could be a warning that COVID may be on a path toward a town near you.
“I could imagine, if there is a new surge happening somewhere in the country and that shows up in the nationwide data, then that might give me a sort of longer-term anticipation that the surge might spread around and I might see it soon,” Leisman said.
While wastewater surveillance isn’t being done everywhere, interest from local health departments continues to grow, says Adriane Casalotti, MPH, chief of government and public affairs for the National Association of County and City Health Officials in Washington, D.C.
Local health departments can share COVID wastewater surveillance reports to help people decide how to manage their risk, such as whether to suspect COVID when someone otherwise might blame similar symptoms on allergies, Casalotti said.
“So much about COVID-19 right now is to know your own health status, know the status of the community around you, and then make the decisions that are best for you,” said Casalotti, whose organization helps create mentorship relationships between start-up surveillance programs and established ones, ranging from San Mateo County in California to the city of Lincoln, NE, and out to Chautauqua County in New York.
If local wastewater monitoring reports are trending upward, it’s time to evaluate your risk factors. Schaffner says that key questions to ask yourself include, “Are you older than 65? Are you frail? Do you have chronic underlying conditions? Are you immune-compromised? Are you a pregnant person? Are you up to date on your vaccines? If you are in any of those high-risk groups, it’s time to get out the mask again and time to think about not going into crowds.”
Schaffner called the currently circulating variants “extraordinarily contagious” and said at his hospital, most people who are being hospitalized are unvaccinated or not up to date with COVID vaccines. Vaccination rates are very low nationwide – only an estimated 22% of adults got the latest 2023-24 version of the shot, and 37% of people ages 65 and older received at least one dose of the newest formulation, which is updated annually. Just 9% of people 65 and older have gotten two doses of the 2023-24 vaccine, which the CDC recommends be spaced 4 months apart.
“It is still no fun to be hospitalized,” Schaffner said, urging more people to get vaccinated. “A hospital, if you have to be admitted, I can assure you it’s not a resort hotel. If you get sick enough with COVID to require hospitalization, you are feeling miserable, short of breath, coughing, feeling really fatigued, you don’t have an appetite, you may well have fever, and you may get some complications.”
Death rates due to COVID have fallen dramatically since the early days of the pandemic, and that’s largely, Schaffner said, because “we are much better at treating people than we were 3 years ago when this virus first hit, so many, many more people are leaving the hospital vertically, as I like to say, rather than horizontally.”
Meanwhile, scientists and analysts are reviewing daily, and in some places hourly, samples taken of wastewater to track virus levels. Officials in rural areas, where private septic systems are more common, have even considered sampling at high-traffic places like schools, hospitals, or even rest stops, Casalotti said.
Using wastewater surveillance for public health purposes isn’t new, although the scope of its use amid COVID is unprecedented. Today, it can also be used to track mpox or identify places where opioid addiction treatment resources are needed. One of the first instances dates back to the 1800s in England, when a London doctor named John Snow attempted to map a cholera outbreak, said Dustin Hill, PhD, an environmental data scientist and postdoctoral researcher at Syracuse University who works on New York state’s COVID wastewater surveillance.
“It was one of the first uses of epidemiology, and he used the wastewater system and water supply to track where the disease was showing up,” said Hill, who also was the lead author of a study published in December that showed how wastewater surveillance can predict COVID hospitalizations more accurately than case data alone.
For those who are monitoring wastewater metrics for signs of whether this current COVID surge has peaked, they may be in for a bit of a wait for the signs of a downturn to show up on colorful line graphs.
“We tend to more look at how it can help us understand the beginning of a new surge, than to try to understand when we’re getting to a peak or getting to a downturn,” Leisman said. “That’s partly because people who have SARS-CoV-2 or COVID tend to contribute it to wastewater beyond when they are recovering or no longer infectious. And so that means that it’s possible that a wastewater surge, while it may start a little bit earlier because people are contributing as soon as they become infected, it may also last a little bit longer, and it’s a little bit less clear how the downturn of the peak would correlate with the downturn of the actual cases or infections.”
