Just when we thought we were out of the Covid woods, researchers at Ben-Gurion University of the Negev are sounding the alarm.

Omicron, the variant that evolved to be somewhat less deadly than previous Covid flavors, may burn itself out in the next couple of months. Omicron and its sub-variants (BA.2, BA.3, BA.4, BA.5 and presumably more on the way) have been so contagious that the previous big bad – Delta – was thought to be wiped out.

Not quite, argue biotech engineering Prof. Ariel Kushmaro and researcher Karin Yaniv in a paper published in the peer-reviewed journal Science of the Total Environment.

They say that Delta has just been waiting for an opportunity to come rushing back in once Omicron is over.

Their distressing prediction comes from monitoring sewage in Beersheva, where BGU is located, from December 2021 to January 2022. Wastewater gives indications of where the coronavirus is active, even as people are testing less.

Kushmaro’s team developed sensitive arrays that can differentiate between variants in sewage. A model built with Prof. Rony Granek revealed the potential resilience of last year’s Covid killer.

“Of course, there are a lot of factors involved, but our model indicates there could be another outbreak of Delta or another coronavirus variant this summer,” warns Kushmaro, whose research was supported by the BGU Coronavirus Challenge and the Israeli Ministry of Health.

Praise from Fauci

A separate team at the university has been part of SAVE (“SARS CoV-2 Assessment of Viral Evolution”), an early detection group associated with the US National Institutes of Health.

Dr. Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases and chief medical advisor to US President Joe Biden, praised BGU Prof. Tomer Hertz and his team for their work on SAVE.

Hertz recently co-authored a paper in Nature reviewing the coordinated efforts of SAVE and its importance for assessing the implications of Covid-19 variants. Hertz and his students “have been generating monthly rankings of SARS-CoV-2 variants based on predictions of their escape from antibodies.” Hertz is also part of a working group that is analyzing T-cell mediated immune pressure on the virus.

Fauci wrote to Hertz that he appreciates “the critical contributions you and your team have made during the ongoing COVID-19 pandemic. Your research has been incredibly important to the fast-paced pandemic response and has supported public health efforts around the world. I recognize that developing the tools and data needed to enable a rapid response to COVID-19 has required a strong work ethic and resilience, and that you have made incredible progress despite many unprecedented obstacles.”

The SAVE methodology serves as a template for the response against rapidly evolving pathogens and may be useful in combating future pandemics. Will that be enough to stop the next post-Omicron variant or a return of Delta?