PHOENIX — Maricopa County is halfway through its serosurvey, and leaders said Wednesday they need help getting people to agree to take antibody tests as part of the project.
The goal of the project is to get a more accurate look at how many people have been exposed to the virus by getting an infection rate beyond those who've tested positive for COVID-19.
"There are a lot of these sub-clinical or asymptomatic infections that ultimately didn't drive these people to seek healthcare, so unless we know how many people have been exposed, we don't know how severe those infections really are in our community," said Dr. Erin Kaleta, the director of the infectious disease laboratory at the Mayo Clinic.
Until September 20, Maricopa County health and ASU crews will knock on doors in 29 communities in zip codes specifically chosen by the CDC to reflect the county as a whole. People can choose to participate in the free testing.
As of Wednesday's update, crews had only reached 63 houses. Marcy Flanagan, the executive director for county health, said they need at least 168 households to make the project valid. The original goal was to reach 210 households and collect between 500 to 1,000 blood samples.
"What we have experienced is that a lot of folks aren't home when we approach their home, so we go back several times. We are still hoping to reach our goal we're really pushing a blitz forward for the next few days," she said. "It's quick, only about 20 minutes for a single person and slightly longer if you have others in your household that participate. You can do it outside of your home or by making an appointment at our mobile medical clinic."
The testing is to identify COVID antibodies, which are proteins the body makes in response to a specific infection.
Dr. Kaleta is testing the samples for the project. "Once that antibody is produced, we don't know who much immunity patients would have from those antibodies or how long that immunity would last. But based on what we've seen so far about re-infection rates from in other large cities, there seems to be some kind of protective immunity that comes after a patient has been exposed to coronavirus," said Dr. Kaleta.
Some community members have expressed privacy concerns about what happens to the blood once it's collected.
"When I get the samples here, it only has a barcode and a number. I don't know who it is, I don't know who's sample it is. We're not saving them, we're destroying them as soon as they're tested," said Dr. Kaleta.
If they don't get enough samples, it's possible they'll have to extend the collection period a few more days. Dr. Kaleta said they're hoping to have the results of the serosurvey by the end of the month.