A test that shows whether a person has had and recovered from COVID 19 shows promise for understanding the virus’ spread in our community. But this data is only a tool, not a panacea.

As antibody testing ramps up in Washington, public officials should take care not to apply the information in ways that get ahead of the science. So-called “immunity passports”— permitting special privileges for people who have had the virus — or abandonment of social distancing rules are a long way off.

State Sen. John Braun, R-Centralia, has called for random antibody testing. In a recent newsletter, he questioned whether the Stay Home, Stay Healthy emergency order and business closures should be continued if widespread random testing reveals COVID-19 has reached a larger-than-predicted share of the population, leading to relatively few deaths.

But that would not answer some key questions. Scientists do not yet know with certainty that once-infected people are immune from reinfection, or how long that immunity might last.

Antibody tests cannot replace widespread testing that identifies active coronavirus infections, or efforts to trace and quarantine people who’ve been in contact with someone with the virus. But antibody tests may be useful in gaining a more accurate picture of the virus’ spread, and in developing treatments or a vaccine.

State public-health officials say they are working with national laboratories and the Centers for Disease Control and Prevention to test leftover blood specimens, including many from Puget Sound area residents, for COVID-19 antibodies. They expect study results within the next few weeks.


The University of Washington Medicine Virology lab recently began antibody testing for medical patients at area hospitals and clinics. King County Public Health is working with the CDC on a possible antibody surveillance system, according to a department spokesman. These developments should give a clearer picture of the virus’ prevalence in the community and its mortality rate.

Random samples in other cities have hinted that the virus had spread much more widely than believed. In New York City, preliminary results showed that 21% of a random test of 3,000 residents tested positive for coronavirus antibodies, The New York Times reported last week. A similar survey in Los Angeles County has led health officials to believe as many as 442,000 adults have been infected — far more than the official 7,994 confirmed cases.

Whether similar results will be found in Washington, and what that should mean for public policy, is not yet certain.

The data will be welcome but must be carefully considered as one of several factors in policy around virus response.