By Amber Brenza

For weeks, the world has been inundated with information about the COVID-19 pandemic. While cases continue to rise and researchers learn more about the novel coronavirus (SARS-CoV-2), most data has lacked a certain specificity needed to ensure that people take this illness seriously. But on Tuesday, the Centers for Disease Control and Prevention (CDC) was able to give a closer look at exactly who is most affected by COVID-19—and its findings underscore the importance of the preventive measures we've all been taking.

In a new study published for the CDC's Morbidity and Mortality Weekly Report, researchers found that the majority of those hospitalized due to COVID-19 have preexisting conditions—about 90% of patients, or nearly all, had one or more underlying conditions. The most common, per the CDC, include hypertension (49.7%), obesity (48.3%), chronic lung disease (34.6%), diabetes mellitus (28.3%), and cardiovascular disease (27.8%).

The data collected for the study came from the COVID-19–Associated Hospitalization Surveillance Network (COVID-NET), created for population-based surveillance for all confirmed COVID-19–related hospitalizations in the US. The CDC's new study used the demographics of 1,482 COVID-19 patients admitted between March 1 and March 30, from across 14 different states: California, Colorado, Connecticut, Georgia, Iowa, Maryland, Michigan, Minnesota, New Mexico, New York, Ohio, Oregon, Tennessee, and Utah.

Age also played a role in the hospitalization rates of COVID-19 patients—the study found that 74.5% of those hospitalized due to coronavirus were age 50 or older, with the highest rates among those over 65. Men were also disproportionately affected (54.4% of those hospitalized from COVID-19 were male), as were African Americans, who represented 33% of hospitalizations, despite only making up 18% of the total population studied.

The study points out that most of the underlying conditions among hospitalized COVID-19 patients are similar to those that affect hospitalized influenza patients, though those with COVID-19 are reportedly hospitalized at a higher rate. (According to data from the 2014-2015 through 2018-2019 flu seasons, 29-31% of hospitalized patients had chronic lung disease, versus 34.6% of COVID-19 patients with lung disease.)

But this isn't the first set of data on the prevalence of underlying conditions among those hospitalized with COVID-19. In a previous Morbidity and Mortality Weekly Report published by the CDC on April 3, it was reported that, among 457 ICU hospital admissions and 1,037 non-ICU hospitalizations, 78% and 71% respectively occurred in those with one or more reported underlying health conditions. Another Chinese study found that, of 1,099 hospitalized patients, coexisting illnesses were more common among those with severe disease (38.7%) versus non-severe disease (21%).

While this research is still preliminary and only accounts for about 10% of the entire US population, researchers maintain that these findings "underscore the importance of preventive measures" like social distancing, regular handwashing, and now, wearing face masks in public settings, in order to continue protecting older adults and those with underlying medical conditions from COVID-19.

The CDC also says that those with underlying health conditions who also have symptoms of COVID-19—including cough, fever, or shortness of breath, among others–should immediately contact their health care provider.