In early April, California’s Santa Clara County reported about 1,000 diagnosed cases of the new coronavirus. But a new study estimates that the real number of infected people was between 48,000 and 81,000. Hoping to determine how widespread the infection was, the county sampled blood from 3,300 residents and tested for antibodies that would show a person had previously contracted the virus. Based on those results, a team from Stanford University thinks between 2.5 percent and 4.2 percent of the county actually had coronavirus, the Los Angeles Times reports. The disparity could be explained by infected people with mild or no symptoms declining to seek medical attention or testing. Results of a similar study in Los Angeles County will be released Monday. “Many more people have been infected with COVID-19 than those who are being captured through our testing,” L.A. health official Barbara Ferrer told the Times.