PORTLAND, Ore. (KOIN) — In a study conducted by the Oregon Health Authority, 1% of Oregonians without COVID-19 had evidence of past infection of the virus in their blood as of mid-June.
The results of the study indicate a “substantial” number of people in the state had undiagnosed and unreported infections from COVID-19. Out of 897 blood samples from 19 health care facilities statewide, nine contained antibodies against the virus. The samples were taken between May 11 and June 15.
The OHA also said the study suggests that rates of infection increased with age, with no antibodies detected in the blood of pediatric patients 17 and younger.
“We suspected that a much larger segment of Oregon’s population has been exposed to and infected with COVID-19 than traditional diagnostic testing shows,” said Paul Cieslak, M.D., a study co-author and OHA medical director for communicable diseases and immunizations. “But these results also tell us that the great majority of Oregonians remain susceptible to this virus.”
The OHA stated a study such as this — called a Seroprevalence survey — may estimate the rate of infection more accurately than conventional testing. However, Cieslak said it’s not the test to get if you think you have COVID-19, as antibodies don’t appear in your blood until weeks after exposure.
“Because most of us are still susceptible,” said Cieslak, “we need to keep practicing physical distancing and masking until we have effective vaccines, treatments or other means of mitigating illness.”
Officials from the OHA will be holding a briefing on Friday to discuss the latest coronavirus updates. KOIN 6 News will update this story when new information is available.