The fear and paranoia surrounding the outbreak of COVID-19 continues without abatement, fueled by incomplete and erroneous communication in both the traditional and social media. This has further stigmatized Chinese and other Asians in an alarming fashion abroad and here in the United States. Asian children are being sent home from school on minor, or without, pretense, and, in general, Asians are increasingly shunned and their businesses are suffering as more and more customers are avoiding them.
As a way of countering these untoward reactions it is time to critically look at the reported numbers and the epidemiological characteristics exhibited by COVID-19. This analysis needs to look at what, on the surface, seems to be two different diseases, COVID-19 within and outside of China, but as we are dealing with the same organism, we have to rather try to explain two different expressions of a single disease.
Scenario 1: Within China. I am well aware of the continued debates as to the data we have seen from within China on the reported number of cases and deaths, but, if anything, they have been consistent in their epidemiological progression. If they have been underreported, it is difficult to see to what end as it is hard to imagine a greater degree of socio-economic damage than we have already seen. Therefore, herein, I take them as published and attempt to understand from that perspective.
The epidemic in Wuhan, Hubei province has resulted in some 75,000 cases and 2000 deaths (2.6%), a devastating epidemic to be sure and a sound reason for global concerns. However, one figure I have not seen discussed is the attack rate, which for Wuhan is approximately 0.6% and for Hubei province as a whole is 0.12% which in itself does not indicate a highly contagious respiratory disease. Another consideration is what percent of cases have been confirmed due to COVID-19 and, more importantly, how many might be due to influenza, another corona strain, or other pathogens. Given the clinical presentations described and the increased mortality, we must assume that COVID-19 indeed accounts for a significant percentage of the reported cases.
This brings up the all-important question of transmission – is this due primarily to human to human spread or is there some other intermediate mechanism such as through vector or fomite? Given our experience with SARS and MERS, human to human is the more likely route and we are dealing with a respiratory pathogen spread primarily through that route. Given the above and given the explosiveness of the outbreak and its apparent increased prevalence in healthcare settings together with the SARS/MERS experience, we are most likely seeing the super-spreader phenomenon at play to some degree. The super-spreader is, unfortunately, one of those concepts easily understood (or misunderstood) but ill-defined as a quantifiable epidemiological construct. To better define, I would turn to Pareto’s principle, more generally known as the 20/80 rule, in which 80% of an outcome (herein COVID-19) is caused by 20% of the affected (herein, the super-spreaders). The 20/80 proportion is not an absolute and, for a given outbreak such as COVID-19, the real ratio might well be 10/20 or 30/70 or some other finite set up to 49/51 but there is no defined cut-point to quantitatively define the concept of super-spreader. One last note in this section on transmission; given the reported ubiquity of the use of masks in Wuhan, I would hope there is a good, retrospective analysis of their effectiveness as a preventive measure during a respiratory outbreak to better inform future public health recommendations.
Scenario 2: Outside China. Before looking at our experiences to date, I would first like to posit that if we accept the super-spreader as contributing to the Wuhan epidemic, than in all likelihood the initial spread of the COVID-19 virus pre-dated the first recognized cases by weeks, if not longer. But regardless of the exact date of the index case of COVID-19 occurred there was a significant degree of national and international travel that occurred before the quarantine of Wuhan was instituted and the total number of exposed individuals to COVID-19 must be significant and extend to virtually every nation. Yet, two months after the first documented cases, not counting the Diamond Princess experience that should be looked at as a separate case, we have just over 500 total cases in 28 countries with 6 deaths (≈1% mortality). Why are the numbers so different than those we see in China when we are dealing with the same microbe and why haven’t more countries reported cases some two months later? I would suggest three possible explanations. 1) super-spreaders occur at very low prevalence and we do not have any outside of China at this time (I would think unlikely); 2) super-spreaders from previous experience tend to be clinical and are being handled appropriately limiting their ability to transmit as per SARS in the latter stages of that outbreak and 3) the quarantine in China has greatly limited the number of cases that could go on to threaten global public health.
I strongly believe a combination of the last two explanations is responsible for what appears to be the successful containment, not elimination, of COVID-19 and we all owe a debt of gratitude to China for what it has accomplished and not the continued criticisms and blame leveled at it. In addition to the socio-economic impacts visited on China and other nations, is the impact on individuals when public health principles are overruled by fear and the national policies that follow. The Diamond Princess is a case in point. Some thirty-seven hundred individuals have been forcibly quarantined in a closed environment with known COVID-19 presence. As that episode winds down, it is interesting to note there have been 621 “cases” identified among 3700 passengers and crew (17%) and it should be most instructive when all the test results are in.
I would like to end this commentary on a personal note. I am originally from Brooklyn, NY – Sunset Park to be exact –which has become one of the most vibrant and largest Chinese communities in the U.S. Now, these Americans of Chinese descent are being stigmatized as a result of COVID-19 and they are, as pointed out earlier, suffering social and economic consequences and without any definable public health concerns or medical rationale – all resulting from the continuing fear and anxiety. Yet, to date the U.S. has experienced but 15 cases (only 2 in New York) and no deaths. Contrast this with the CDC reported 26,000,000 – 36,000,000 influenza cases and 14,000 to 36,000 estimated deaths this season and yet most Americans do not even take the flu vaccine. There is something terribly wrong with this picture. It is time to face our fears. We, as a people, preach and supposedly embrace diversity and inclusiveness, it is time to put our words into action. As a start maybe we should think of holding a National "Hug an Asian" Day.