In ordinary times, a new report describing experiments on bits of smallpox scabs nestled in Civil War museum artifacts would have been mildly interesting. But these days, clues in old poxvirus genomes are especially intriguing because they may explain how some people resist COVID-19, perhaps thanks to a past run-in with a different coronavirus. According to another recently published study, these individuals haven't tested positive for COVID-19 or SARS or had contact with people who have, yet they have immune memory – T cells that recognize a coronavirus that infects bats.
Could exposure to one type of coronavirus protect against infection by another?
"The origins and genomic diversity of American Civil War era smallpox vaccine strains," published in Genome Biology, looks at a possible precedent to answer that question. Such cross-reactivity happens when an antibody or T cell recognizes a surface molecule common to more than one species of pathogen. It's a little like recognizing Eric Clapton in different bands.
A Brief History of Smallpox Vaccination
To continue reading, go to DNA Science, where this post first appeared.