Researchers found a significant increase in referrals of patients with signs of respiratory diseases at the end of last year.
The deadly coronavirus may have been spreading in the US as early as December last year, which is about a month earlier than the Federal centers for disease control and prevention (CDC) thought.
This is evidenced by data from researchers from the University of California at Los Angeles.
Their study, published in the Journal of Medical Internet Research, found a statistically significant increase in visits to clinics and hospitals by patients who reported respiratory diseases as early as the week of December 22-28.
According to the CDC, the first confirmed case of COVID-19 in the United States was detected in January in a patient from Washington State who had previously visited Wuhan, China.
Dr. Joanne Elmore and her colleagues examined about 10 million medical records from the University of California, Los Angeles health system, which includes three hospitals and 180 clinics.
“As for outpatient patients, I found a 50% increase in the number of patients who came with cough complaints. This is more than the average that we would normally see, by more than a thousand people,” Elmore told CNN.