Question: Italy and South Korea both have similar case counts, but South Korea’s mortality rate is much lower. What’s driving the difference? Similarly, Japan has twice the population size of Italy, but far fewer cases and deaths. Why have these countries suffered so differently?

Answer: The true answer to this question will make a fascinating public health dissertation. I’m going to focus on the Italy/South Korea issue here since Japan has a more localized epidemic than either of the other two countries. As of March 10th:

· Italy has 10,149 confirmed cases, of whom 631 have died which gives a crude death rate of 6.2% — far higher than the WHO’s estimate (3.4%) and far higher than the mortality rate of South Korea, which has 7,513 confirmed cases with 54 deaths (0.7%)

· Italy also has an aging population with half of the population over age 47. Indeed, nearly a quarter of Italy’s population is age 65+, whereas South Korea’s population is younger with only 16% of the population age 65+ (note: for the United States, 17% of our population is age 65+). [if you like population data, see here]

· Because COVID-19 hits the elderly the hardest, we would expect to see higher mortality in countries with larger population of older folks.

· Based on the experience in China, we also saw much higher mortality in Wuhan, the epicenter of the outbreak. This is likely a result of an overloaded health system that was unable to adequately take care of those in need. We are witnessing an overloaded health care system in Northern Italy, which is also a reason why we are seeing increased mortality.

· There are probably myriad other factors, including socio-cultural factors, smoking prevalence, the speed of the initial public health response, and more.

Question: If I a person is self-quarantined, what does this mean for their interactions with others in their household? Are they also required to self-quarantine?

Answer: CDC has a great list of 10 things you can do to manage your health at home if you fear you have COVID-19. As much as possible, try to avoid your family members! If you do have to self-quarantine, here’s HHS guidance. While not a given, it’s likely your household members will also need to follow self-quarantine guidelines; by the time you are identified as being at risk, you’ve probably already been in close proximity with those living in your household.

Question: What’s the status of high–throughput tests? Rapid diagnostic tests?

Answer: High-throughput tests (also called automated tests) are for use in a diagnostic system that can process 1,000 tests in 24 hours. Yesterday, HHS announced it was partnering with Hologic, Inc through BARDA to develop such a system for COVID-19 testing. Per the announcement, “BARDA and Hologic expect that necessary development will be completed in a matter of weeks which then would allow the U.S. Food and Drug Administration (FDA) to consider granting Emergency Use Authorization (EUA) for the diagnostic test.” With regard to rapid diagnostic tests, several companies are working on development, which will allow doctors, nurses, or even individuals themselves to conduct COVID-19 tests (depending on the test type). Here’s one example. Generally, rapid diagnostic tests result in higher rates of false-positives than PCR-based tests, which is an important distinction early in an outbreak when we are working to find every case and their contacts (e.g. we do not want to waste resources investigating non-cases). At this stage, however, rapid diagnostic test kits in harder hit communities would be welcome. The Gates Foundation is working on home-based test kits for pilot in Seattle.