Not a myth! Healthy younger adults with no underlying medical conditions can develop severe Covid-19, warns CDC

The majority of coronavirus-associated hospitalizations occur in adults aged 65 years and older and/or those with underlying conditions, according to health experts. However, younger and healthy adults have not been spared either. Adults in the 18-49 age group with no underlying health conditions can still develop severe Covid-19, warn researchers. 

The analysis, conducted by the US Centers for Disease Control and Prevention (CDC) and other experts, suggests that among 513 adults aged 18-49 years without underlying medical conditions hospitalized with coronavirus during March-August 2020, 22% were admitted to intensive care unit, 10% required mechanical ventilation and three patients died (0.6%). 

“Our study showed that, among younger adults hospitalized with Covid-19, more than 1 in 5 of those without underlying medical conditions experienced severe illness requiring ICU-level care and other interventions. Our findings reinforce the need for social distancing, rigorous hand hygiene, and use of masks to prevent infection, even among young adults considered to be at relatively lower risk for severe coronavirus,” recommends the team. 

What did the investigators find?

From March 1-August 1, 2020, 44,865 patients hospitalized with Covid-19 were identified. Adults aged 18-49 years old represented 31.8% (13,167) of all hospitalized patients. “Of the 13,167 patients, 3,720 (28.3%) had medical chart abstractions completed. Among these 3,720 patients, (2.7% or 101) did not have information on underlying conditions. Of the remaining 3,619 patients, 14.2% (513) had no underlying conditions and were included in the analysis,” reveals the report, which has been published in Clinical Infectious Diseases.

The most common symptoms present at admission were cough (67.1%), fever/chills (64.7%), and shortness of breath (63.4%). In total, 34.9% of patients (179) were prescribed treatment for Covid-19, and 22% (113) were admitted to the ICU. The median hospital length of stay was four days and the median length of ICU stay (among those admitted to ICU) was five days. Analysis of the three patients who died during hospitalization reveals that the number of days from symptom onset to admission ranged from six to 15 days, and the number of days in the hospital ranged from 13 to 36 days. All were admitted to the ICU and required invasive mechanical ventilation. 

“Within a large, geographically diverse surveillance network of laboratory-confirmed Covid-19-associated hospitalizations, adults aged 18-49 years accounted for about one-third of all hospitalizations. In contrast, adults aged 18-49 years have made up 13%-23% of patients hospitalized with influenza over the past 5 seasons,” write authors. 

The researchers say that while evidence shows that older age and certain comorbidities are risk factors for severe coronavirus, the mechanisms behind severe Covid-19 in younger adults without underlying conditions are not well understood. Emerging evidence indicates that biological factors may explain why some individuals develop severe Covid-19 and others do not, they add.

The analysis also shows that approximately 74% of adults aged 18-49 years without comorbidities who were hospitalized with Covid-19 were males. “These findings suggest that, in the absence of underlying conditions, male sex may increase the risk of severe Covid-19, leading to hospitalization and the need for intensive care in adults under 50 years,” says the team.

Many young Americans have also lost their lives

From March 1, 2020, to July 31, 2020, a total of 76,088 all-cause deaths occurred among US adults aged 25 to 44 years, according to a separate study. This was 11,899 more than the expected 64,189 deaths, write authors in JAMA. Of these, 4,535 coronavirus deaths were recorded, accounting for 38% of the “measured excess mortality.”

“Only 38% of all-cause excess deaths in adults aged 25 to 44 years recorded during the pandemic were attributed directly to Covid-19. Although the remaining excess deaths are unexplained, inadequate testing in this otherwise healthy demographic likely contributed. These results suggest that Covid-19-related mortality may have been under detected in this population,” say researchers from Brigham and Women’s Hospital, Boston; Yale School of Medicine, New Haven; and Massachusetts General Hospital, Boston, among others.