According to a modelling study conducted in Israel, the Omicron subvariants may burn out in the coming months, and another outbreak of Delta or a different coronavirus strain could occur this summer.
The discovery, which was published in the journal Science of The Total Environment last week, suggests that while Delta wiped out the variants that came before it, Omicron hasn’t wiped out the deadly variant that could resurface.
Researchers from Israel’s Ben-Gurion University of the Negev (BGU) developed sensitive arrays that can distinguish variants from each other in wastewater, providing clues as to where the coronavirus is active even as PCR and rapid testing of people decline.
They observed a “disturbing interaction” between the Omicron and Delta variants in sewage in Beer-Sheva, Israel, from December 2021 to January 2022.
The researchers also created a model that predicts Omicron will burn out while Delta will simply bide its time.
“Of course, there are many factors at play, but our model suggests there could be another Delta or coronavirus variant outbreak this summer,” said BGU Professor Ariel Kushmaro in a statement.
Until now, according to the researchers, whenever a new dominant variant appeared, it quickly overtook its predecessor after a brief period of parallel evolution.
In contrast to the expected dynamics, in which the Delta variant decreases as the Omicron variant increases, the results of wastewater detection revealed a cryptic Delta circulation even with higher levels of Omicron, they said.
“According to the developed model, Omicron levels are expected to decrease until they are eliminated, while the Delta variant will maintain its cryptic circulation,” the study’s authors wrote.
“If this occurs, the cryptic circulation mentioned above may result in the reemergence of a Delta morbidity wave or the possible generation of a new threatening variant,” they added.
According to the researchers, including BGU’s Karin Yaniv, Omicron is rapidly spreading around the world, with high rates of morbidity.
The dynamics of the Omicron variant have shown different characteristics than the Delta variant, which was previously thought to be the main variant of concern in most countries, they said.
The use of wastewater-based epidemiology is recommended as a convenient and cost-effective method, according to the researchers.
