“Serosurvey” will estimate how much of Maricopa County’s population has been infected with COVID-19
PHOENIX (September 2, 2020)—Maricopa County Department of Public Health (MCDPH) is embarking on an investigation to estimate how many people in Maricopa County have been infected with COVID-19, beyond those who have had a positive diagnostic COVID-19 test. This project, done in partnership with Arizona State University (ASU) and Mayo Clinic, will collect samples from volunteers in 29 communities across the county to estimate how many people currently have antibodies for COVID-19.
“We know that, especially early on in the pandemic, not everyone who was infected was tested. We also know that around 40% of people infected with COVID-19 never develop symptoms and may not be included in our case counts,” said Marcy Flanagan, executive director for MCDPH. “By conducting this serosurvey, we will have a better estimate of how many people throughout our county have the antibodies to COVID-19 and how many people need to be vaccinated to reach community immunity.” Community immunity, also known as herd immunity, is when enough people in a population are immune to a disease so that the disease cannot spread efficiently.
MCDPH and ASU worked with the Centers for Disease Control and Prevention (CDC) to implement a method of sampling a small number of households in targeted communities that would represent all of Maricopa County. The CDC gave MCDPH and ASU a list of 29 communities within the county, which will be statistically representative of the entire county.
“This Investigation will provide public health with really important information to help us understand when we can recommend relaxing social distancing and other strategies like mask requirements.” said Flanagan. “Ultimately, we will use the information to help us all get safely back to normal,“ she added.
Residents of the 29 selected communities will receive a door hanger next week to notify them of their eligibility for participation, inform them of the goals of the project, what it involves and provide a way to get more information. Volunteers from MCDPH and ASU will then visit those communities between September 12-20, 2020, to invite residents to participate in the free antibody testing for the serosurvey.
If interested, residents will be able to answer questions about their health and prior exposures to COVID-19 outside their home or at a mobile clinic. Then, a sample will be collected, which will be tested for COVID-19 antibodies by Mayo Clinic. Participants will receive their test results by phone within 7-14 days of participation. All information will be kept confidential, and no government entity outside of public health will receive any information collected in the serosurvey. Maricopa County will destroy any specimens collected after the information is analyzed and the information will never be released with identifying information.
To keep volunteers and residents safe, volunteers will wear personal protective equipment (PPE), will not ask to enter residents’ homes, and will follow safety protocols.
For more information on the serosurvey, including how to tell if a person is part of the serosurvey, please visit Maricopa.gov/COVID19serosurvey.