COVID-19 ticks up in wastewater — Are we in the midst of a new surge?

Experts disagree about whether the slight upswing means a big increase in cases or just a temporary rise.

This electron microscope image shows SARS-CoV-2 virus particles which cause COVID-19, isolated from a patient in the U.S., emerging from the surface of cells cultured in a lab. NIAID-RML via AP

Boston’s COVID-19 wastewater tracker has begun to tick slowly up again over the past couple of weeks, as it has in the past before most surges.

Experts disagree about whether the slight upswing means a big increase in cases or just a temporary rise.

The latest data from the COVID-19 wastewater tracker shows that current levels are similar to those from early February.

The upward trend comes as the omicron BA.2 variant becomes the dominant one in Boston, The Boston Herald reported, and most pandemic safety mandates in the city have been lifted.

The average COVID-19 levels in wastewater hit a low at the beginning of March, hovering around 100 RNA copies per milliliter. Now, the average levels are above 300 RNA copies per milliliter.


In November and December, scientists accurately predicted the omicron surges in late December and January based on this type of data.

Then, in mid-January, COVID wastewater data was used to accurately predict the stop of the omicron surge that happened in early March.

COVID wastewater levels are still far below what they were during the first omicron surge. At that time average levels of COVID in wastewater reached 11,500 RNA copies per milliliter.

Verge of a surge?

Still, some experts believe it is highly likely that we are on the verge of the next surge.

Matthew Fox, a professor of epidemiology and global health at Boston University, said he thinks it’s very likely that Boston will soon see a sharp rise in case numbers.


Fox said that infectious diseases like COVID-19 follow a cyclical pattern of surges and lulls, so we can expect surges to continue until the virus becomes a regularly occurring virus like the flu.

“I’m still optimistic that it will be a less severe wave in terms of deaths and hospitalizations,” he said.

Davidson Hamer, a Boston University School of Public Health infectious disease specialist, told the Herald he also believes the next surge is now upon us.

“The gradual upward trend in the wastewater is worrisome,” he told the newspaper. “The good news is that it has been a slow upward trend.”


Hamer told the Herald that the upward trend is likely a result of the spread of the BA.2 variant, reduced mask use in public places, and people being less cautious about getting the virus.

Still, he told the paper, hospitalization numbers haven’t increased much, so that at least is not currently a public health issue.

Just a blip?

But not all COVID wastewater experts are so sure that the uptick of COVID in wastewater is a harbinger of the next surge and not just a temporary increase.

Philip Landrigan, a pediatrician and the director of Boston College’s public health program, said that this increase is what the beginning of every surge looks like, but that there’s no guarantee that there will be one.

“The big question is, is this the leading edge of a surge, or is it just a blip?” he said.

Landrigan said the only way to know for sure what the uptick will bring is to keep a close watch on COVID wastewater numbers.

Sheree Pagsuyoin, a professor of civil and environmental engineering at UMass Lowell, agreed with Landrigan, saying that when comparing the current uptick to what we’ve seen before past surges, this one seems minor.

Pagsuyoin said increases have gone back down without becoming a surge before, so she’s not that worried right now.


“We can’t rule out the possibility of a surge, but there’s no reason to panic,” she said.

Pagsuyoin said it’s important to monitor the uptick, but the fact that it’s a slow climb and not a rapid increase is a good sign.

Johnathan Levy, the chair of the environmental health department at Boston University, also said it’s too early to tell whether or not a big surge is to come.

Levy said it’s clear that COVID cases and test percent positivity are rising in Boston, and that the UK is currently dealing with a BA.2 surge comparable to the original omicron surge. Even so, he said, COVID has proved itself to be an unpredictable virus.

“It’s possible that we’ll just have a smaller blip here as we enter the warmer weather, or it’s possible that we’ll have a fairly large surge,” he said.

Reasons to be hopeful

Though Massachusetts has a high rate of vaccination for the U.S., with 70% of the population fully vaccinated, Levy noted that the state lags when it comes to people getting boosters. This makes residents here less prepared to deal with another surge as compared to those countries like the UK, he said.

Experts agree that there are reasons to be hopeful. If there is a surge, it might not be as bad as the last one, because many people have immunity to the omicron variant due to vaccination or being infected. Still, they said, there is no way to predict how high cases could climb.

They also agreed that the BA.2 variant seems to be about as severe as the original omicron variant when it comes to causing symptoms, hospitalizations, and deaths.


Even though the omicron variant is known to be milder than previous variants, that doesn’t mean it can’t do significant damage, experts said. BA.2 is significantly more transmissible.

“Even with a weaker strain, you can still have a lot of hospitalizations and deaths because it’s reaching so many people,” Fox said.

As of April 5, Boston is experiencing 29.3 new cases a day per 100,000 people on average. The city’s goal is to lower that rate to 10 new cases per 100,000 residents per day. However, it’s still far below the threshold at which the city said it may reinstate COVID safety policies, which is at 50 new cases per 100,000 per day.

The city’s COVID test percent positivity rate as of April 5 is 5.4%, which is above the city’s threshold of 5%.

Experts agree that it’s time for us to prepare for a surge by getting ready to wear masks in crowded spaces again and cutting down on social interaction.

Reducing the risk

“Think about small ways you can reduce your risk of getting COVID,” Fox said. “Don’t go out as much, go to fewer large gatherings. You don’t have to stop doing everything you love.”

As for public policy, such as mask and vaccine mandates, experts said it won’t be clear what officials should do until it’s clear how bad the surge is.

Still, Levy said, both the public and the government should not wait to act and risk hospitals filling up when there are strong warning signs.

“It’s better to act early, meaning starting masking in crowded indoor settings, certainly getting as many people boosted as quickly as possible, to blunt the possibility of a substantial wave,” he said.


“It’s hard to know when that moment arrives, but it’s certainly better to act with some precaution and avoid bad outcomes than to wait until something very bad happens and wish that we had done something.”

But most importantly, experts agreed, that for those who haven’t been vaccinated or haven’t gotten a booster shot, now is the time. The best way to prevent a surge is to increase vaccination rates, they said.


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