JEFFERSON CITY, MO – The Missouri Department of Health and Senior Services (DHSS) continues to partner with the Missouri Department of Natural Resources, the University of Missouri – Columbia, wastewater operators, and others to monitor COVID-19 trends by testing wastewater in communities throughout the state.
In February 2021, this team began testing wastewater samples to look for the presence of variants of the virus that causes COVID-19. Using a technique called high throughput sequencing, samples with sufficient COVID-19 genetic material are tested for genetic mutations, which are compared to mutations in known variants.
The testing results are now displayed in a new layer of the COVID-19 sewershed surveillanceStoryMap.
In press releases issued on February 26 and March 9, DHSS announced initial rounds of this testing, which suggested the B.1.1.7 (UK) variant virus was present in sewage samples in some locations throughout the state.
This sequencing testing now suggests the B.1.1.7 (UK) variant is present in all areas tested across the state. B.1.1.7 is considered a variant of concern in part due to evidence of its increased transmissibility. Other mutations associated with other variants of concern seen by this testing include B1.427/B.1.429 (South California), Brazil, and South African; however, these mutations have tended not to be as consistently present as the B.1.1.7.
Even though these mutations are present, viral load levels remain relatively stable. This stability suggests that efforts to minimize transmission of the virus are working, and stresses the importance of continued testing, vaccinations, and adherence to local recommendations to stop the spread of the virus.
Viruses constantly change through genetic mutation. As the COVID-19 pandemic has progressed, several variants of the COVID-19 virus (SARS-CoV-2) have emerged. Some variants may have a selective advantage due to their specific mutations, which is why some variants can become dominant over the “parent” strain (original strain of the virus). Advantages may include how easily variants spreads from person to person.
For the genetic sequence testing, small sections of the total COVID-19 RNA strand are being analyzed. Because the entire genetic sequences are not being analyzed, the results do not confirm the presence of an actual variant; however, they are suggestive of the presence and distribution of variants across the state. While wastewater testing can be a useful tool for screening for the presence of variants, sequencing of a clinical specimen is required to confirm their presence.
“In some communities, we are consistently detecting the same mutation week after week, serving as a signal of the presence of these correlating variant(s) in the population. In other communities, results are inconsistent between weeks,” said Jeff Wenzel, Bureau Chief of Environmental Epidemiology. “Several reasons could cause this to happen. One possibility is travelers or visitors passing through could be contributing to variation, or person(s) cease shedding after recovery from the infection.”
Despite uncertainties, these results are useful for informing public health investigations and response for stopping the spread of COVID-19. Washing hands, wearing masks, testing, social distancing, and vaccinations have slowed the spread of the virus. The emergence of variants emphasizes the importance to continue efforts to minimize transmission including continued testing, becoming fully vaccinated, and adherence to local recommendations to stop the spread of the virus.