The 5% of the Population at High Risk for Severe COVID-19 Infection Is Identifiable and Needs to Be Taken Into Account When Reopening the Economy.

The goal of this column is to help mental health care professionals understand coronavirus disease 2019 (COVID-19) so that they can better explain the complexities of the current crisis to their patients. The bottom-line of this column is that, while COVID-19 can infect virtually everyone in the human population, only about 5% are susceptible to severe infection requiring admission to an intensive care unit and/or causing a fatal outcome and this population can be identified on the basis of comorbid medical illness and/or age. These numbers are based on experience in China, the United States, and Europe. Table 1 presents an analysis conducted by the US Centers for Disease Control and Prevention (CDC), which is further supported by several other sources reviewed in the article. The population at risk for severe infection are individuals with comorbid medical illness and those 85 years of age and older. The comorbid medical illnesses identified as risk factors are preexisting respiratory and cardiovascular disease, immunocompromised status, morbid obesity (ie, body mass index ≥40), diabetes mellitus, and possibly significant kidney or liver impairment. Parenthetically, news reports and the literature sometimes cite age 60 years and older as a risk factor but age between 60 and 85 years is likely a surrogate for having 1 or more of these comorbid medical conditions. While 5% may initially seem like a small number, it nevertheless potentially represents 16.5 million people, given the United States population of 330 million. That is a tremendous number of people requiring intensive care unit admission and/or potentially dying, and individuals in this population have overwhelmed the US health care system in some hotspots. For this reason, this column suggests taking this at-risk population into account in mitigation strategies when attempting to open the US economy. The column addresses the following questions: (1) What are the 3 aspects of the race to minimize the damage caused by COVID-19? (2) What data are currently available to help guide decisions to be made? (3) What strategies have been employed to date and how successful have they been? and (4) Might risk stratification of exposure be a viable strategy to minimize the damage caused by the virus? The race to minimize the damage caused by COVID-19 requires that we obtain knowledge about the disease and its treatment or prevention, how to best safeguard public health and avoid overwhelming the health care system, and how to minimize the societal damage caused by substantial disruption of the economy. Data gathered over the past 4 months since the COVID-19 virus emerged as a human pathogen have provided guidance for our decisions going forward. The most widely adopted strategies for dealing with the COVID-19 pandemic to date have involved the epidemiological approach of encouraging good hygiene practices and social distancing, including orders to "shelter in place," quarantine of high-risk individuals, and isolation of infected individuals. The goal of this epidemiological approach has been to "flatten the curve" by reducing the height of the peak of the infection to avoid overwhelming the health care system and society in general, while buying time to learn more about the disease and find more effective ways to deal with it. However, now that more is known about COVID-19 and the portion of the population that is most at risk for serious adverse outcomes including death, it may be possible to move from a shelter-in-place approach for the entire population to focus on those at most risk and thus facilitate a gradual and rational phased reduction of social restrictions to reopen the economy. Such a graduated opening would be based on regions of countries meeting specific criteria in terms of being able to contain the virus, coupled with vigorous monitoring to look for outbreaks, followed by case monitoring, isolation of infected individuals and quarantine of exposed individuals, and increased use of testing for active disease as well as for immunity. Taking the data on high-risk individuals into account would allow for a gradual lifting of restrictions on the majority of the population while maintaining more stringent safeguards to protect the vulnerable portion of the population. Nevertheless, the entire population would need to continue to practice good hygiene and social distancing while simultaneously-and perhaps even more vigorously-focusing on sheltering the vulnerable population until adequate community immunity has been achieved to prevent the spread of the virus, whether that is accomplished through natural exposure alone or with the addition of safe and effective vaccine(s) which may not be available for a year. Continued widespread testing for antibodies will help determine how far or close this country is-and other countries are-from developing effective community immunity.