As new cases of Covid-19 reach record levels in the United States, there’s new evidence the novel coronavirus SARS-CoV-2 that causes the disease has been with us much longer than previously thought.
Researchers from the University of Barcelona say they detected the virus in sewage samples were collected in the Spanish city on March 12, 2019. That’s several months before the first cases that would lead to the current pandemic were officially identified in Wuhan, China in early December.
It’s previously been reported sewage samples suggested the coronavirus was present in Spain in mid-January of this year, over a month before the first case was confirmed there.
The team analyzed frozen waster water samples from nine different dates between January 2018 and December 2019. All the samples came back negative for the presence of SARS-CoV-2 genetic material, except for low levels that were found in the March 12, 2019 sample.
It’s a little odd, to say the least, that the coronavirus popped up only once in Barcelona’s wastewater nearly a year before Spain reported its first cases.
“When it’s just one result, you always want more data, more studies, more samples to confirm it and rule out a laboratory error or a methodological problem,” Dr Joan Ramon Villalbi of the Spanish Society for Public Health and Sanitary Administration told Reuters. “It’s definitely interesting, it’s suggestive.”
In their summary of their findings, the team makes a point to note the oft-repeated theory that some particularly rough influenza cases that were reported in the months prior to the new coronavirus emerging may have actually been Covid-19 cases.
“It has been suggested that some uncharacterized influenza cases may have masked COVID-19 cases in the 2019-2020 season,” the Barcelona researchers write.
“Those infected with COVID-19 could have been diagnosed with flu in primary care by mistake, contributing to the community transmission before the public health took measures,” adds co-author Albert Bosch in a statement. Bosch is also president of the Spanish Society of Virology.
It’s important also to note that this research has not yet been peer reviewed, which is a key part of the scientific vetting process prior to publication in a journal. However, given the need for information on the origin and spread of the pandemic, many scientists are publicly sharing and promoting their data prior to publication, but it should still be treated as preliminary and taken with a grain of salt.