A new study finds that at least 11 people infected with COVID-19 traveled to Arizona and passed the disease to others.
Those infections started local transmission chains that seeded the state's earliest coronavirus outbreaks starting in mid-February. Researchers from the Translational Genomics Research Institute and Arizona's three universities reached that conclusion as part of an extensive effort to sequence the genomes of virus samples. They found that 80% of infections in the early phase of the outbreak stemmed from those 11 people. They also determined that a person who became Arizona's first case of COVID-19 after traveling in China did not infect anybody else after he was isolated.