Question: What would the data have to look like to know if what we are doing is working? And what if we still don’t have enough tests?

Answer: I especially like this question — it’s a monitoring and evaluation question and M&E is my jam! So prepare for a long-ish answer.

First, let’s just quickly outline what we want to know:

1. What are we doing (outputs)? (ex: percentage of population that is practicing social distancing; percentage practicing correctly)
2. What are we seeing (outcomes)? (ex: daily number of new infections, hospitalization #s/rates, intensive care #s/rates, virus mutation rates)
3. Why does it matter (impact)? (mortality rates, reproduction rates, vaccine/treatment effectiveness)

Without either: a) widespread testing; or b) effective population-based surveillance, tracking changes in reproduction rates (R zero) and mortality rates will continue to be a challenge. So, instead of focusing on impact, we need to focus on the outcomes, where we have better data. Here, our indicators include:

• Number of hospital admissions (daily, weekly, cumulative)
• Number of ICU admissions (daily, weekly, cumulative)
• Number of deaths (daily, weekly, cumulative)

For each of these indicators, we’d want to understand how affected vulnerable communities are, so we’d also want to disaggregate the data at least by age (typically 5-year age bands), underlying health conditions (e.g. heart disease, lung disease), and health worker status. We’d also want to continue to track virus mutations to understand how it is changing. These data, which scientists share via the online platform, GISAID (more on that below), will help us to know how effective our vaccines may be.

Now that we’ve got our indicators, we also need to remind ourselves that our what we are doing now will only be made visible in the future… we have to get Back to the Future! (just watched all 3 movies with my 7-year-old, Great Scott!) Since it takes on average 5 days for an infected person to begin to show symptoms and since it takes an additional 5+ days for a person with symptoms to become seriously ill, the folks who are showing up to hospitals now became infected at least 10 days ago, but probably even longer than that. Since we just started social distancing on 3/16(ish), we wouldn’t expect to see a decrease in the number of hospital admissions now… we need to wait still a few more days, and even more days for ICU admissions, and more for death. Really crudely — 5 days to feel sick, +5 more days to feel really sick, +X days to be admitted to ICU, +X days to die. So, we should expect to see our outcome measures (above) continue to worsen in the immediate term. If our social distancing now is effective, we’d expect to start to see hospital admissions decline in about 2 weeks or so (back of the envelope guess). But that decline will be a decline not from the numbers we’re seeing today, rather from the higher numbers we’ll be seeing two weeks from today.

If you want to know more about influenza monitoring (which is pretty close to COVID-19 monitoring), check out CDC’s weekly influenza report. Australia also has a nice description of its influenza surveillance framework here.

Question: Do we know if there is any potential for the Coronavirus to mutate, and what are the signs that a mutation has occurred?

Answer: Yes, this coronavirus, like all viruses, has the potential to mutate. (see Q&A from 3/11 and 3/19). Scientists around the world continue to monitor mutations via genomic sequencing data that are shared on the GISAID platform. Good news is, SARS-CoV-2 seems to be mutating at a very slow rate. Yesterday, the Washington Post had a great article on this very topic. So far, scientists are seeing very few mutations, they have found no evidence of a specific virus “strain” to increased severity, and they think this is great news for having a vaccine that will work for a long time (like measles rather than flu).