Colorado has a growing number of reasons to be hopeful it can relatively weather the COVID-19 pandemic, but contact tracing isn’t one of them.
There’s no doubt that this tried-and-true system of methodically mapping the path of carriers of disease among others who could become victims is a useful way to limit the transmission of contagious maladies. For years, the spread of AIDS, caused by HIV, was provably limited by contacting people who had sex with someone who was infected.
The novel coronavirus — the disease it causes, and the rate and path of infection — is nothing like HIV.
What state and federal officials hope to do is have a contact tracer, sort of a disease investigator, talk to everyone that that has come in contact with someone testing positive for COVID-19 — for up to two days before symptoms of illness emerged. When someone waits for a couple of days to see if their summer allergies warrant a test, which takes a couple more days to return results, and then more time for the contract tracer to call, nipping the virus in the bud at that rate will be only marginally helpful.
So far, “contact” is defined as spending 15 minutes or more with someone closer than 6 feet. At this point, wearing a mask doesn’t affect tracing protocols. Two months ago, when nearly everyone rarely left home, this might have been a manageable feat. But as Colorado “re-opens,” accurately recalling these possible encounters going back two days and forward possibly several days will be increasingly difficult.
Experts say the average incubation time before symptoms appear is about 5-6 days. It’s likely then that someone newly infected will begin shedding the virus to others before they’re contacted by a tracer, unless the process is accelerated.
That’s not likely. Tracking down multiple contacts won’t be the hardest part. The sheer volume of the task will likely prove overwhelming. One local expert predicts that each case a tracer investigates will require an average of 10 contacts.
That’s important because, currently, Tri-County Health is reporting a three-day rolling average of about 60 positive tests each day, the lowest it’s been in weeks. It means that Tri-County Health alone is facing having to contact about 600 people a day, every day. As cases increase, which they’re certain to do since people are getting back into public encounters, the process of contact tracing slows down, allowing more potentially infected people to infect others.
Those numbers are just for Tri-County Health. Colorado is currently reporting about 225 daily positive tests, based on a three-day rolling average. Right now, the statewide rate of infection for tested people is about 5%. It means that, since the state is currently testing only people who have symptoms, that the approximate 4,000 tests conducted every day reveal about 200 infections. And as Colorado makes good on promises to increase testing, the burden on contact tracers will only increase. Currently, Colorado is conducting about 70 daily tests per 100,000 people in the state. Federal health officials say the testing rate needs to be more than double that to successfully monitor the outbreak. So even at the current level of infection, contact tracers are looking at about 500 cases a day, requiring an average of 5,000 contacts. When the virus becomes wider spread again, those numbers increase exponentially.
This doesn’t even account for the difficulty in tracing people exposed on airplanes or who come here from out of state or leave to another place. Compounding the complication of this process limiting the spread of the virus is whether tracers can get accurate and complete lists of contacts during an investigation. Given the political pushback on wearing masks and limiting public businesses and events, it seems likely many people won’t give up information.
Similarly, there’s no sense of how compliant pandemic naysayers, or anyone, will be pushed backed into home quarantine for 14 days after months of isolation.
Even if it were pulled off with even modest success, this program only focuses on people exposed to the virus who become sick and get tested.
It doesn’t mean that the state has or should be silent to COVID-19 victims contacting people they might have exposed. But since state and local health officials are so keen on voluntary compliance with all sorts of pandemic protocols, rather than spend millions on a tracing program too easily overwhelmed, testers can instruct patients how best to reach back to those possibly exposed.
While it’s unknown how many people shedding the novel coronavirus have no symptoms at all, many experts estimate that as many as half of everyone infected unknowingly spread the virus. Contact tracing does nothing to directly curb the spread of the virus by people who have no symptoms. Even if tracers were able to contact and contain every person possibly exposed to someone sickened by the virus, tens of thousands of people would not be identified.
It all points a marginal return on what could be a massive public investment costing tens or even hundreds of millions of dollars. While this would certainly be useful in parts of the state with little virus activity or all of the state when the virus is reduced to dozens of new infections each week instead of hundreds, the massive amount of money this program could burn through, or more, would almost certainly be better spent in hardening virus protocols in nursing homes, schools and supporting essential businesses employees forced to work in less-than-safe conditions every day. It would be wise for Colorado to prepare for such a project, but it will be folly to enact it statewide right now.