Wastewater COVID numbers soared in late summer ahead of possible fall wave

WORCESTER, Mass — A temporary rise or the start of something bigger? Epidemiologists can’t predict what’s next for Covid-19. But one indicator suggests the virus may be getting a foothold -- one that could mean a wave in the fall.

CDC, WHO tracking a new ‘highly-mutated’ strain of COVID-19 variant

Biobot Analytics reports the amount of Covid in wastewater rose sharply from July to August -- more than doubling nationally, from about 240 copies per milliliter to more than 500 copies. That is still a relatively low number, said Cristin Young, MPH, PhD, an epidemiologist with Biobot -- with levels in July five times lower than what Biobot measured the same time last year.

“We were in a pretty high plateau for most of 2022, then it started to decrease to levels that we saw in 2020 and 2021,” said Young.

(For perspective, at the height of the Omicron wave, wastewater concentrations of Covid exceeded 4,000 copies per milliliter.)

While Covid-19 has not proven to be a true seasonal virus, it does seem to follow patterns of infection that pivot on geography and resultant togetherness. In past summers, Covid cases tended to rise in hot parts of the country, as residents of the South and West sought refuge in air conditioned spaces. In Northern states, outbreaks usually hit in fall and winter, as residents escaped the cold.

“I’m not surprised that we’re seeing an increase,” said Young. “It’s summer, people might be spending more time inside, especially with the heat waves we’ve been having.”

Those historic heat waves are likely only part of the reason for Covid’s resurgence. At this point, immunity, for millions, is waning and just as new variants have emerged. The most important of these carry a spike protein mutation known as F456L. One of them, EG5, now accounts for about 20 percent of cases nationally, according to the CDC.

Sandeep Juball, MD, is an infectious disease physician and medical director of the Covid Treatment Center at UMass Memorial Health. He said for much of the summer, he saw a steady trickle of patients.

Now it’s more like a torrent.

“Past, I would say, two or three weeks, there’s been an uptick in the number of treatments we are providing in our center,” Juball said. In fact, the number of patients has risen about six-fold in recent weeks.

“I expect this number to go up,” Juball added.

One wild card in Covid’s deck: an emerging, massively mutated variant known as BA.2.86. So far, five cases have been confined to four countries -- the UK, Denmark, Israel and the United States. What concerns researchers about BA.2.86 -- also known as BA.X -- is that its dozens of mutations are to the spike protein -- the very structure targeted by vaccines.