Abstracts of these resources are available in the searchable Information Portal offered to Northwest Biosolids members.
Is it finally time to take our masks off? Turns out that the best place to look for an answer to that question is in the sewer. We last looked at detecting Covid in wastewater in September, 2020 or about a thousand years ago. That was before we had opinions about Pfizer versus Moderna, before we had to relearn the Greek alphabet, and before our mask wardrobes expanded well beyond other day to day accessories like shoes. It was also back when wastewater- based epidemiology (WBE) was a potential tool for tracking Covid outbreaks. Now it is spring 2022 and some States, Countries, and lots of individuals have already decided that it is time to take off the masks. I read today that soon we’ll be allowed to be tourists in Australia!! Not before masks are allowed off on planes in my case, but still, this is hopeful news. And in the vein of hopeful news, this month’s library will focus on just how successful WWBE has turned out to be.
The first article is from the Morbidity Mortality Weekly Report, not the most optimistic name for a journal. It reports on the progress of WBE for tracking Covid across the US. Initial work on tracking Covid in the sewer was limited in utility because different places used different methods for collecting and testing. This made comparisons of results problematic (note relevance to PFAS here). As the pandemic wore on and the utility of WBE became clear, the CDC stepped in to help standardize measuring and also reporting. In fact, results of wastewater monitoring are now featured on the CDC Covid website: https://covid.cdc.gov/covid-data-tracker/#wastewater-surveillance. The article details efforts in UT and OH. The authors also note that everyone poops, and most of us poop into centralized collection systems. The important point there is that by using WBE you can get a view of Covid spread that cuts across age, race, economic status and access to health care and testing. This makes wastewater based information less biased than some other methods of following spread of the virus.
From here we go to one of several articles I found that detailed the use of wastewater tracking to control the spread of the virus on college campuses. While there was also an article on Notre Dame and another from Tulane, I picked the one from Arizona where our very own Ian Pepper is the corresponding author.
Here is the graphical abstract from that paper.
By relying on WBE, the authors were able to quickly identify a dorm with positive cases. Testing followed soon after the wastewater detection and three students, two of whom were asymptomatic, were found to be positive and isolated, effectively halting the spread. From there surveillance expanded and was used to identify outbreaks in multiple dorms. The authors note that shutdowns were effective and that cases increased after breaks. In other words, the tool worked and was able to keep campus open.
The next article takes us to Ottawa, a step up from dorms to a city wide surveillance program. The authors were sampling clarified sludge every other day during the summer of 2020. Back then the sunshine and warm temperatures coupled with people paying strict attention to masking and having regular old not nearly as transmissible Covid going around, case counts were very low. In Ottawa the daily positivity for testing was less than 1%. It was the sewer that sounded the warning. If memory serves me right, that was the Alpha outbreak but at this point, who knows. At any rate in July the scientists found an increase in wastewater counts of over 400% and they found it 48 hours before the big spike in cases showed up in testing. Testing reported increases of 300%. About four days later, hospitals started seeing their loads increase by more than 160%. In other words, WBE was able to sound the alarm and allow for the city to prepare several days before the new outbreak hit. Not sure if anyone honked the horn about the virus before the truckers drove in. Right now, there is a big crisis in Ottawa as a result of protests by truckers over vaccine mandates. I would imagine that a lot of wastewater samples are being collected as a result.
(New York Times)
From Ottawa we go to the world. The 4th paper in the library reviewed the literature available on WBE for articles published before the end of July 2021. They identified 92 studies from 34 countries that were deemed to be of sufficient quality to be included in the review. This means over 25,000 samples from communities with as little as 321 people to as big as 11.4 million people. Across all studies the findings echoed what was seen at the U of A and in Ottawa. A minimum of 50 of the studies detected viral loads in wastewater that increased with case counts in the community. Thirteen of the studies found positive detects before the tests did. The paper is filled with tables that go through the pertinent studies and have information on where samples were taken, viral loads, sample positivity and association with conventional testing results. The information is there for the asking. Primary point is that WBE works.
And that is what is scary/ fun/ worthy of a movie about the last paper in the library. The findings of this paper just hit the news the other day. Researchers have been tracking Covid in NYC and have done deep sequencing of the viruses that they have identified. Lately they have found a sequence that is not associated with any known variant. This is as cases of Omicron in NY are falling rapidly and as the Governor of NJ has just announced that masks will no longer be required in schools. You can see the map below (NYT) where the dark colors mean not out of the woods and the lighter colors signify (perhaps) the edge of the forest. New York is all lighter colors.
These new sequences have a lot in common with Omicron. They are resistant to the monoclonal antibodies that have been effective at fighting the other forms of the virus. No word on how the vaccines or the new pills stand up against them. The authors hypothesize that these sequences could be from infected people whose particular version of the virus has yet to be sequenced outside of the sewer. They could also be from infected animals.
If the previous studies in the library are correct- this last study suggests that maybe if you do take your mask off, don’t throw it away just yet.
Stay healthy and welcome to Spring!