Question: There have been concerns about the long term health effects of many of those who recover from COVID-19, such as lung scarring and liver damage. What do we know about the permanent or long term health effects from other similar infections?
Answer: It’s true, we still don’t know the long-term sequelae of COVID-19. Some very preliminary data from Hong Kong that you cite in your question show diminished lung capacity among those recovered, but we just don’t have enough information yet to know what (if any) the prolonged impacts of COVID-19 may be. Looking at other coronaviruses could give us a clue. With the SARS outbreak of 2003, various studies found that lung function was diminished over time among those who recovered. A more recent study published in Nature found that “The most severe sequelae after rehabilitation from SARS are femoral head necrosis [e.g. hip joint doesn’t get enough blood and dies] and pulmonary fibrosis [e.g. damaged lung tissue that makes it hard to breathe].” Another paper looking at long-term effects of MERS also found that “Lung fibrosis may develop in a substantial number of patients who have recovered from Middle East respiratory syndrome coronavirus (MERS-CoV).” We will know more as more folks recover.
Question: The numbers you presented yesterday seem to be worst-case scenario type numbers. What’s up?! First, tell me what the numbers would be not in worst-case scenario. Then, describe for me how these mortality numbers differ from underlying mortality estimates.
Answer: If you want expert opinion, please read the report that the Imperial College COVID-19 Response Team released yesterday. [It won’t make you feel any better.] For the estimates I presented yesterday, I used the early-stage case fatality rates by age-group estimates from the China CDC. I haven’t seen any other age-specific case fatality rates, but I do acknowledge that these represent one place and one time point for an evolving pandemic. The case mortality rates will vary based on a range of factors and, fingers-crossed, the rates will be lower than these early numbers from China. As to typical mortality in the US, CDC has data on age-specific mortality and I’ve copied the table for 2018 herein for comparative purposes. I also changed the assumptions of the data I shared yesterday such that age-specific mortality is 1/2 that of what was shown in China and 30% of people become infected (see chart below). In this better-case scenario, we still have 568K deaths, which is equivalent to 20% of all deaths in the US in 2018. These are all estimates and we can change the estimates not just by changing our assumptions, but also by changing our behavior. My original purpose in showing age-specific mortality yesterday was to remind us that COVID-19 is not just a disease of the elderly. Even though mortality rates are much lower among younger ages, the threats of inaction or too little action are threats to us all.
