AIMING FOR THE TARGET
Public health adds new tool to fight against COVID-19
Webster County Public Health has begun to incorporate a new tool in the fight against COVID-19: targeted testing.
As coronavirus infections show no sign of ebbing while businesses reopen, targeted testing can help identify more infections faster, preventing outbreaks from starting or stopping a growing one in its tracks. It’s particularly helpful for places where large populations of susceptible people live or work together.
With nurses suited up in protective gowns, masks and face shields, WCPH goes to the site requesting targeted testing to test all its employees or residents at once.
The tool has become critical in the fight to protect residents of nursing homes, who are acutely vulnerable to severe complications from COVID-19 and rely on employees that come in from the outside each day.
“Long-term care populations are vulnerable, so they need to be a top priority,” said Kari Prescott, director of WCPH.
But the tool is useful for other public health priorities whose populations might not be vulnerable, but have to report to work every day, like essential factories, agricultural processing facilities or meat packing plants where it’s difficult to socially distance.
Prescott said that some positive test results from the few sites they’ve visited since targeted testing started last week have been from people who were asymptomatic or showed more minor symptoms–not the severe respiratory symptoms recognized more quickly.
About 80% of those with COVID-19 will show mild or no symptoms, public health officials have said frequently. Symptoms general take anywhere from two to 14 days after the point of exposure to manifest. By identifying more cases faster, those who are asymptomatic and would have continued with business as usual can be stopped from unknowingly spreading the virus.
Businesses eligible for targeted testing must be classified as essential to receive the no-cost service.
“Supplies are provided to use at no cost to the business, so we want to be good stewards of those supplies,” Prescott explained.
Often, those calling in with concerns have had a risk of exposure from someone who tested positive in their agency or business that could necessitate blanket testing. Public health works closely with administrators and managers to coordinate the service.
Last week, WCPH helped three sites outside Webster County, using its larger staff to help bolster efforts with other rural counties less equipped to handle a surge of cases. Recently, WCPH assisted Buena Vista County, which saw a sudden surge to 134 cases (as of Thursday) that puts its infection rate higher than Linn and Johnson counties–Iowa’s original epicenter of COVID-19 infections.
“In this surge, (other counties) need a little bit of help,” said Prescott.
Targeted tests are timed to ensure multiple tests are not needed later, using contact tracing to take into account the incubation period and delay of symptom onset with COVID-19 in a group. Test too soon, and you run the risk of not identifying enough positive cases. Test too late, and a virus outbreak could already be out of hand.
A diagnostic test is “only a snapshot in time,” Prescott said, noting the WCPH is being “very diplomatic” about its contact tracing to coordinate a large number of stakeholders across multiple counties.
And if tests are snapshots, public health nurses have become ad hoc photographers, capturing a virus too elusive, by its nature, to be detected by the human eye.