Mike the Mad Biologist

Today’s post is going to focus on D.C.’s response to COVID-19, not only because it affects me personally (important! To me!), but because it’s small enough that it’s possible to wrap our heads around the natural history. A good day in D.C. with one out of 100,000 people infected would yield seven new cases, and we can understand each of those cases; by contrast, a good day in California means around 400 new cases per day.

Also, last week, there were some local fireworks when the D.C. Council asked some softball questions to the D.C. Health commissioner (boldface mine):

While D.C. Council members questioned the city’s progress in identifying new sources of infections, Maryland lawmakers inquired how the state calculates its test positivity rate and why it differs from other health experts’ data….

In Washington, members of the D.C. Council on Wednesday asked Health Director LaQuandra Nesbitt about the city’s slow progress in identifying sources of new coronavirus infections, which could lead to shutting down activities such as indoor dining.

For weeks, Nesbitt has said the city would ban certain activities if data from contact tracing showed the need for it, but the city has not added restrictions. The reason, Nesbitt said, is that the Health Department hasn’t determined which activities are leading to infections.

“We still have a very difficult time creating for our population what their source of exposure is,” she said on a call with council members. “When I have something I can raise that recommends anything be scaled back, I will do that.”

In response to questioning from council members, she added: “Sometimes the tone and the tenor of these questions are completely insulting, as if we are not doing our level best to stem the tide. We’re trying to do our best to communicate how hard we are working to get ahead of this thing.”

Nesbitt said the Health Department is doing what it can, including making visits to workplaces if more than one employee at a business contracts the virus. She cited research that the department is conducting to determine what activities infected people have participated in — potentially spreading it to others — as opposed to what activities led someone to catch the virus.

In a sample of 100 people, she said that 24 had eaten inside a restaurant while they were infectious; at least five were government employees who went to work; and 10 had traveled by plane, train or other mode of transport.

To be clear, I don’t think D.C. Health has done a bad job, though, as we’ll get to, some improvements need to be made. And the contact tracers are doing the work from what I can gather (again, we’ll get to that). Anyway, onto the questions D.C. Council members should ask D.C. Health, with explanations of why this matters:

1. How much 24-hour turnaround time testing capacity, if any, does D.C. currently have? How much of it is being used, if any, in contact tracing (as opposed to clinical diagnostics and other clinically-related activities)? Leaving aside discussions about the technology of rapid diagnostics (e.g., paper strips etc.), it is not impossible–at all–for a facility with enough PCR machines and other equipment to process thousands of samples per day. D.C. is small enough that we could easily test one percent of the population per day. That turnaround time is critical for contact tracing.
2. If D.C. doesn’t have that capacity (or enough capacity), what would it take to gain that capacity, in terms of equipment and personnel? D.C. Council members and Mayor, now is not the time to be penny-wise and pound-foolish.
3. What would it take to be able to focus equally on how the patient became infected along with whom they might have infected? Jumping ahead here a bit, but if we’re not trying to determine the source of the infection, then how do we control it?
4. Given that other areas and studies have concluded certain activities, such as indoor dining can result in infections, why are we not shutting down these risky activities? What would constitute clear evidence that these activities have led to outbreaks, and how would you gather this evidence (and are you able to do so at this time)? As noted above, if you’re not really attempting to determine the sources of outbreaks, then… how do you determine the sources of outbreaks? And if you can’t do this, why are we not rolling back immediately. Admittedly, there are probably more than a few local politicians who are perfectly fine with not knowing these answers–don’t have to shut anything down that way–but for the rest of us who don’t want to get sick or die, this question is kinda important. Ask this (that goes for journalists too).
5. Does the city need to be more aggressive in shutting down workplaces? Given testing delays, accessibility to testing, as well as the significant fraction of asymptomatic people, should we be visiting workplaces when one person tests positive? Yes, this is a leading question, but if we wait for two positives from a workplace, we’ll never find any links. We have to be more aggressive here.
6. Is the contact tracing going deep enough on individual cases? While there might not be (probably isn’t) enough capacity to really drill down on every case, is there at least a subset of cases where we’re doing this? Related to this, to what extent are we bringing the testing and questions to potentially infected people–getting in cars and going to where the people who need to be tested are? Compared to a typical FDA foodborne infection investigation, we’re not really running down leads. Doing this, even on a small subset of cases will provide answers about spread and probably find new cases.

This is by no means exhaustive, but it’s a start. Local politicians and journalists need to start asking these questions (especially #1 and #4). If we don’t understand spread (or are pretending to not understand spread), then we need to rollback. Now. It’s only our lives at stake…

Update: After writing this (but before publication), D.C. released some information (pdf) about what they have found–it’s not particularly informative, but it is interesting that travel, especially air travel and rideshare, seem linked to infection.

On the whole. Wards 2, 4, and 8 are doing a little better, while Wards 3, 5, and 7 are doing worse. Overall, the prevalence in D.C. has increased:

Only Wards 1 – 3 would be above the German rollback threshold of 50 new cases per 100,000 per week (0.05% in the second column above); D.C. as a whole also exceeds the threshold. We’re slowly losing ground overall, and citywide the prevalence rate is about ten times higher than what would allow us to resume normal-ish activity. Really, the only good news is that we’re doing enough testing.

I’ll have more to say about D.C.’s ongoing failure to lower the curve on Wednesday, but it’s really unclear right now what the strategy is, other than hoping for the best–which isn’t a strategy at all. Since D.C.’s testing and tracing strategy doesn’t seem to be designed to understand spread, but to prevent further spread, we don’t know where how transmission is occurring, which is being used as an excuse to not shut down anything, even as prevalence is rising.

The shame of it all is that, if we went hard at this, we could be back to normal-ish by October easily. D.C.’s problem is that we are four weeks away from solving this–and we are always four weeks away because we aren’t willing to do the obvious things to crush the curve. And, as I’ll note on Wednesday, those who purport to lead us don’t know the right questions to ask.

Anger is still the appropriate emotion.