Towards the end Last year, U.S. health authorities received a warning about an upcoming wave of respiratory syncytial virus, a seasonal virus that kills 160,000 people worldwide every year. Before hospitals reported an increase in the number of patients, they could see that RSV was sharper in the northeast of the country, where virus concentrations eventually reached levels more than five times higher than in the western United States. Your early warning system? Sewage.
By periodically testing virus levels in public wastewater, healthcare institutions can direct treatments and interventions to the most affected areas before doctors on the ground realize something is happening. “If you can get information to hospitals or clinics weeks ahead of time, that gives them an opportunity to start thinking about what treatments they might need,” says Marisa Donnelly, senior epidemiologist at Biobot Analytics, which helped develop a surveillance system for wastewater for US Centers for Disease Control.
RSV is very common: every year, 64 million people around the world get an RSV infection, according to the U.S. National Institute of Allergy and Infectious Diseases, but it is particularly problematic for the very old and the very young. Preventative measures are available, including vaccines and monoclonal antibodies. But often, by the time a community recognizes it has an RSV outbreak, it is too late to mount the most effective response. It can also be difficult to get enough medications. “Wastewater analysis provides a better situational understanding of what is happening and how much it fluctuates over time, because (historically) we have underdetected many cases of RSV,” says Bill Hanage, associate director of the Center for Dynamics of Communicable Diseases at Harvard TH. Chan School of Public Health.
The concept of tracking a virus through wastewater gained importance in the early days of the Covid-19 pandemic in 2020, says Tyson Graber, an associate scientist at the Children’s Hospital of Eastern Ontario Research Institute, who worked on the wastewater testing as part of Ontario’s Covid program. answer. At first, researchers didn’t have much hope. “No one thought you could actually detect fragments of material from a respiratory virus,” says Graber. However, it turned out to be possible: scientists were able to detect the presence of SARS-CoV-2, the virus behind Covid-19.
This near real-time analysis of the spread of the virus helped improve responses to the pandemic not only in Ontario, but around the world. In the United States, the CDC launched its National Wastewater Surveillance System in September 2020.
While each pathogen has its own “predilections and eccentricities,” Graber says, it was possible to adapt the process to look for RSV. Regular testing for RSV in wastewater is currently performed in the USA, Canada, Finland and Switzerland.
a study Ontario’s experiment on wastewater monitoring for RSV found that it provides more than a month’s notice to identify when RSV season begins, and almost two weeks’ notice of an increase, compared to waiting for people to get sick . “We definitely see increases in RSV in wastewater before we see those same increases in clinical data like hospitalizations,” Donnelly says.