In yesterday’s post I wrote that Quest Diagnostics was offering Covid-19 testing effective today. I explained how important that was to rational clinical decision-making during this epidemic, especially given the really limited availability of clinical viral testing through the CDC or the Mass DPH. My bubble of happiness has been burst.
Quest Diagnostics reneged on their announcement midday today. In Massachusetts, availability is now scheduled for two weeks from today, according to my local Quest contacts. This is a major disappointment and a real setback to rational clinical care. I had spent hours over the weekend working with them nationally and locally to arrange tests for several members. For naught. Not happening.
As a country and as a medical practice we are really flying blind as to the extent and growth rate or detailed person-to-person spread of this epidemic infection because we don’t have testing capability for asymptomatic or mildly symptomatic people to determine if they are carrying the virus. The only testing available (from the state or CDC) is for people who are substantially ill (though they may have regular flu) or were in direct contact with someone known to have Covid-19 while that person was symptomatic.
We are embarrassingly behind in testing capability. We should have had widespread availability of point-of-care tests (as we do in our office for influenza, for example) two months ago. The problem was known. The technological capability is certainly there. Whatever the root cause, this is a major fail for the American health system. I speak as an internist and also as member of a local board of health. Back in January, with plenty of testing, we might have been able to isolate individual cases, trace their contacts, quarantine a limited number of people, and contain the epidemic. That time has come and gone.
Community spread occurring
We are now in the time of community spread, by my estimate and stated or implied by true experts such as Dr. Anthony Fauci of the NIH. That means that so many people have been exposed and are now likely incubating the disease that you will see increasing numbers of cases with no specifically identifiable source. And many of those clinical presentations will be indistinguishable at the start from the many other respiratory infections from rhinovirus, adenovirus, influenza, other coronaviruses, parainfluenza viruses and more.
Infectivity during incubation?
The only way of easily, clearly and promptly identifying people with Covid-19, which is quite contagious and to which no one has immunity, is by testing early on, including asymptomatic people who had casual contact with someone who later develops the disease. There is little question that someone with fever of 102F and a severe cough is infectious. What about an asymptomatic but infected person’s contacts for the first 5-14 days, the likely maximum duration of the incubation period? Are they at risk? And with community spread, there are many people walking around who have been infected but are still incubating. We just don’t know who they are. Nor do they.
So far the the CDC and state labs implicitly think the risk of such infectivity during incubation is zero, since they do not support testing such casual contacts. Our two patients, whom I was unable to get tested in the past several days, are in this category. But is this true? And, more important do we just think it is true or do we know it to be true?
No real data on infectivity during incubation
In fact we do not have enough testing data in this epidemic to state definitively that there is no risk of infection from a person incubating Covid-19. It has not really been studied so far (fair enough). For many viruses, people are contagious during incubation; for some that is not true.
How do we deal with that lack of knowledge? Right now, limited testing by CDC and state labs in reality reflect the scarcity of available tests, not greater wisdom. They do not know that there is little infectivity during incubation; they are hoping it is true and directing their limited resources to test higher-probability risk contacts. Effectively they are rationing these important tests. In the U.S. This is the unstated profound embarrassment for our government.
Broad testing needed during community spread
With the rising ambiguity of sources of infection with community spread, and with lots of potentially infected people unknowingly in contact, a strategy of broad and early testing of asymptomatic people is logically critical. While the pickup may be (and we hope it will be) relatively low, lots of tests will identify unknown carriers and allow us to protect each other more effectively than now. We will make extensive use of the Covid-19 testing to help protect Orchard Health Care patients when the test finally becomes available in two weeks.
Keep tuned. This story is not over.
On March 10, the CDC advised that even healthy people over age 60 should stay home.
It is true that the mortality rate in this age group is higher than for younger people. However, the incidence of conditions making people more susceptible to getting seriously ill is much greater too, so it’s unclear to me how much of the incremental risk is due to age.
I am therefore wondering if the CDC recommendation is evidence based, or the CDC is just being cautious because it doesn’t trust people to know when they have health conditions that could put them at significantly greater risk.
Excellent point, and I believe the answer is that this has not been fully elucidated. I believe the observations are both that older people are more susceptible and also that those who are in addition dealing with significant underlying heart disease and diabetes or on treatment with any degree of immunosuppression are at even higher risk. We will get more data with time, assuming we get adequate testing done, which we finally are being able to do.