COVID-19 could have been in US as early as December, according to new study - The Mercury News

In a study published Thursday in the Journal of Medical Internet Research, the team of nine researchers compared electronic medical records in the UCLA Health system from this winter to the previous five years and found an excess number of outpatient and emergency room visits with complaints of a “cough,” as well as hospitalizations for acute respiratory failure, beginning the week of Dec.

From then through the end of February — a 10-week span — they estimated there were 1,047 more outpatient visits, 514 more emergency department visits and 387 more hospitalizations than their model would have anticipated, suggesting “community spread of SARS-CoV-2 prior to established clinical awareness and testing capabilities,” the researchers wrote.

“While asymptomatic transmission and community spread of COVID-19 are possible explanations for the observed excess patient encounters, other reasons and limitations need to be considered,” researchers wrote.

Some other reasons, researchers said, could be the early and especially strong peak of the 2019 flu season in Los Angeles, the mysterious vaping disease of 2019 or possibly more people seeking out medical advice for COVID-like symptoms once it gained media coverage in February.

Even compared to the worst flu season of the past five years, researchers found there had been hundreds of more cases of “cough” being reported at clinic and emergency rooms around the city.

The UCLA Health system provided them records of 9.5 million outpatient visits, 575,000 emergency department visits and nearly 250,000 hospital admissions from January 2014 through February 2020.

Researchers used data from the previous five years to determine a seasonal average for December through February, then compared it to this year’s data to see how many excess visits there were outside a 95% interval of what was expected for that period.