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COVID-19 cases in Illinois continue to grow, increasing by 1,826 to 36,934 as of April 23. Evanston reports 273 total cases.
Adjusted for population size, Evanston has a greater number of cases than the state. This could be due to higher levels of testing of Evanston residents, almost double the state average. Currently, tests in Evanston are registering a 15% positive rate for residents versus 22% for the state.
Note – as of April 23, 2020; Source: IDPH, Evanston Department of Health and Human Services
Testing has increased over the past few months and is close to reaching Governor J.B. Pritzker’s goal of 10,000 tests per day.
Evanston Hospital, part of the NorthShore University HealthSystem, is a significant testing lab in Illinois, conducting around 1,200 per day, or about 18% of the state total.
Karen Kaul, M.D., Ph.D., Chair, Department of Pathology and Laboratory Medicine at NorthShore University HealthSystem, and her colleagues began developing an in-house diagnostic test for COVID-19 in late January after watching what was happening in China. “At the time I thought I was over-reacting, but I guess not,” she reflected.
Thus far, testing has been limited and used primarily to triage people into hospitals or into isolation. “We are just testing the tip of the iceberg – people who are clinically symptomatic,” she said. “But there are a lot of people I suspect that had minimal symptoms and we aren’t testing them presently,” said Dr. Kaul. “We really don’t know the prevalence of this disease in our society,” she concluded.
Supply chain issues are the immediate bottle-neck; there are not enough nasal swabs to collect samples from patients and chemical reagents can be scarce. “I’ve never found myself in my 30-year laboratory career dealing with the supply chain issues we’ve had over the past couple of months,” Dr. Kaul observed. “Companies who make the parts to do these tests can’t instantly increase their production in a week; it takes time.” She concluded that they still have a way to go to obtain enough test materials, but it is improving.
Sufficient laboratory staff to perform the diagnostic tests is also a limiting factor, although not in her lab. Dr. Kaul explained that the Protecting Access to Medicare Act (PAMA) reimbursement cuts to clinical lab tests by the Centers for Medicare and Medicaid Services (CMS) has led to understaffing at many labs across the state and country. Her team really out did themselves by volunteering for extra training and extra shifts to expand the testing.
According to Dr. Kaul, daily diagnostic testing should be several times the current levels before relaxing restrictions and opening up society, but she cautioned that she is not an epidemiologist. Many public health experts have stated that significantly higher levels of testing are necessary to monitor the prevalence of the virus over time.
There is still much the medical community does not know about this novel coronavirus. This lack of knowledge, plus the scarcity of vital test materials, presents challenges to testing more broadly, including individuals who are asymptomatic, and obtaining accurate results.
Testing to date has been based on the tried and true polymerase chain reaction (PCR) technology. This process detects the presence of the RNA of the novel coronavirus in mucus of a patient collected by a nasal swab.
Dr. Kaul noted, “We suspect patients are shedding the virus before they show symptoms. That is well established, but we don’t know how many days before.” The number of days after infection the average person starts to shed the virus and thus is detectable by the PCR test may vary by person and could be determined by how significant the initial exposure was. If the test is done too early, after infection but before shedding occurs, the test may not detect the virus and could give people false assurance. It may be necessary to swab and test the same person twice, a few days apart, to obtain accurate results. This increases the need for more tests, she concluded.
Serology tests will be an important tool to help hospitals triage patients and determine how widespread the disease is in our community, she noted. Serological tests detect specific antibodies the immune system produces in response to an infection. This is a way to identify people who have had the virus.
Dr. Kaul referred to a large scale serology study by Beaumont Health, the largest healthcare system in Michigan. Beaumont Health is conducting serological testing on all its 40,000 employees. The results of this study may tell us something about the prevalence of the disease in Detroit area and serve as a model for other communities.
Dr. Kaul and her lab have begun evaluating a number of serology tests that have been recently introduced. “There are nearly a hundred different serology tests, few of which have been reviewed at any level by the FDA,” she noted. Serology tests will initially face the same supply chain issues as the PCR tests.
NorthShore will be able to conduct small volume serology testing soon, said Dr. Kaul. And her lab is working on getting serological instruments that will facilitate high capacity testing, because it will be necessary to test broad swaths of our population, she explained.
The ability to conduct both tests – the diagnostic PCR test and the serology test – will allow hospitals to again perform necessary medical procedures that have been postponed for the last several months to free up space and resources to treat COVID-19 patients. “We will need both tests to give us a full picture of who is at risk, ill, and recovered from COVID,” stated Colette Urban, Director of Public Relations at NorthShore University HealthSystem, in an email. She added, “We will use these tests to triage patients coming in for surgery or other procedures in our hospitals.” Discussions about proper screening to protect both patients and staff are underway now.
It is still unclear whether testing serologically positive for COVID-19 means an individual is immune and protected against infection. “That is the big question on everyone’s mind. But we are all hoping that the presence of antibodies will confer some immunity,” emphasized Dr. Kaul. Answers still remain to important questions such as: What level of antibodies confer immunity? How long will this immunity last? Will it be similar to the common seasonal flu where the virus changes a bit and we have one vaccine and then a few years later, another vaccine?
It is not clear that Illinois has reached the peak in new cases quite yet, noted Dr. Kaul, although the rate of increase in new cases has slowed.
“I would have hoped that when we went on Shelter-at-Home orders that we would have had two weeks and then we were to start to see some drops in new cases, and we don’t.” Dr. Kaul attributed the continued rise to community spread “by whatever contact is taking place.” She discounted a longer-than-thought incubation period [14 days] as contributing to the continuing rise in cases.
Dr. Kaul is thinking ahead, about preparing for the next outbreak. She stressed the need to develop infrastructure – a network of hospital, public health and commercial labs and a framework of communication and processes between these entities and the CDC – in place “so that we can be ready for when this happens again three to five years from now or whenever that will be.”