New preliminary research suggests a dominant strain of coronavirus may be more contagious than others.
A virologist at the National Institute of Allergy and Infectious Diseases (NIAID) who reviewed the study said the findings suggest the virus may have become more contagious and could possibly be responding to health measures such as social distancing and mask-wearing.
Other experts questioned the study, saying they have yet to identify a mutation that would change how infectious or deadly the virus is.