ORANGE COUNTY, Calif. - Coronavirus infections in Orange County were found to be seven times higher than previously thought, according to the results of a UC Irvine study released Wednesday.
County officials hired UCI to do a serological study of a large cross-section of residents to check antibodies for COVID-19 to get a better handle on how prevalent the highly infectious disease has been in the community, according to Orange County CEO Frank Kim.
The study showed that "the disease prevalence is about seven times greater than previously identified by positive tests," Kim said. It also showed that coronavirus infections were also "greater in Latino and lower-income residents, which we knew because they had a higher positivity rate," he said.
Reasons for higher infection rates in Latino neighborhoods include"higher density housing" and "less access to quality health care," Kim said.
Another obstacle is fear among some Latinos of participating in any government-run programs for fear of deportation, he said. The reluctance to get tested can help fuel the spread of the virus, particularly among those who do not show any symptoms, Kim said.
"Some don't want to submit to government testing, so if you don't test you might transmit it to a family member," he said.
Kim said officials in surrounding counties, especially in migrant communities, say it is a thorny problem.
"My peers are telling me it is a disaster because they won't come out to test even though it's free," Kim said of many migrant workers. "Some people in our community are fearful of anything involving an official branch of government. We found that out with the census, as well."
Positivity rates are determined from polymerase chain reaction, or PCR, tests, which involve a health professional using a swab of the nasal cavity and are considered the most trustworthy when determining if a patient is infected.
The accuracy of serological, or blood tests, to determine if a person has developed antibodies to COVID-19 is considered less accurate.
UCI researchers sought to improve on the accuracy of blood tests by recruiting "subjects outside of a clinical setting" and by using "strategies to minimize bias of recruiting mostly symptomatic cases."
The scientists also applied a technology they say has "superior sensitivity and specificity relative to what were currently available FDA-approved tests used by others" who have conducted similar serological studies, according to UCI.
The researchers also "recruited a sufficiently large sample of adults to calculate seroprevalence by race/ethnicity, age and gender, which may uncover important differences across these groups," according to UCI, and used a questionnaire "without initially disclosing an offer for an antibody test."
The study focused on adults in the county and reflected the demographics of the region.
The 4,555 participants were tested at drive-thru sites from July 10 through Aug. 16. Of the subjects who participated, 65.4% showed up to provide a blood sample.
The study showed that 11.5% had antibodies for COVID-19, much higher than previous estimates of less than 2%.
Among Latinos, the rates were as high as 17% and 15% for lower-income residents.
"The reason the county and HCA engaged UCI to conduct the widespread antibody testing is to learn exactly what we learned today, which is how prevalent COVID infection has been in our county, but we didn't want to wait until these results before we took action," Orange County Supervisor Andrew Do said.
"Therefore, Supervisor (Doug) Chaffee and I, as part of the (board's)testing ad hoc committee, proposed the Latino Health Equity Initiative and, subsequently, the Asian Pacific Islander Testing Program to address the hotspots that we had already seen in those communities."
Supervisor Lisa Bartlett said the study "allows us to focus on those areas" that need extra attention. Bartlett pointed out that the high-density housing in Latino neighborhoods are often multi-generational, as well, so there is a greater risk of exposing older, more vulnerable adults to the virus.
The county "started the Latino Health Equity Initiative well before" the governor introduced a metric for counties to meet with lower-income communities, Bartlett said.
From July through this month, the county has seen a 74% reduction of COVID-19 infections in the county's hot spots, Bartlett said.
"It's a matter of getting the word out there to get tested if you have symptoms and not be afraid," she said.
"We have free testing throughout the community. That's how we're going to eventually overcome COVID-19 -- by making sure people get tested when they need to get tested and we do contact tracing and people get quarantined."