The Centers for Disease Control and Prevention says efforts at airports in California to fight the coronavirus through contact tracing were ineffective in preventing the spread of COVID-19.
From Feb. 5 through March 17, officials at a number of California airports identified more than 11,500 visitors who arrived from China and Iran. The goal was to keep track of people from high-risk countries as part of a contact tracing effort. But the sheer number of people, along with a high level of inaccurate contact information, made the system ineffective, the New York Times reports.
Three people recorded at California airports were later found to have COVID-19 from the list of cases collected by the state.
The CDC reported that nearly 1,700 hours of personnel time, was used to try and accurately keep track of the visitors but that the system was still overwhelmed.
The CDC says the state didn't have complete passenger information and officials may have missed asymptomatic cases. The agency recommends improving the collection of personal information and contacting at-risk travelers as soon as possible.