The notion gained traction particularly among people who claimed that this existing protection would swiftly bring human populations to herd immunity, the point at which a pathogen’s spread slows to a halt as it runs out of hosts to infect. A study in the journal Science, published in December, gave the hypothesis a strong boost.

But for all its appeal, the theory does not hold up, according to a new study published on Tuesday in the journal Cell. Based on carefully conducted experiments with live virus and with hundreds of blood samples drawn before and after the pandemic, the new research refutes the idea that antibodies to seasonal coronaviruses have any impact on the new coronavirus, called SARS-CoV-2.

“Going into this study, we thought we would learn that individuals that had pre-existing, pre-pandemic antibodies against SARS-CoV-2 would be less susceptible to infection and have less severe Covid-19 disease,” said Scott Hensley, an immunologist at the University of Pennsylvania. “That’s not what we found.”