To say that you’ve revealed the emergence of a more transmissible form of SARS-CoV-2 without ever actually testing it isn’t the type of thing that makes me feel comfortable as a scientist.” She and other virologists I’ve spoken with who were not involved in the Los Alamos research agree that the paper’s claims are plausible, but not justified by the evidence it presents. More important, they’re not convinced different strains of the coronavirus exist at all.