Why Coronaviruses Hit Older Adults Hardest

Posted:February 27, 2020

As cases of the novel coronavirus known as 2019-nCoV continue to rise worldwide, preliminary estimates suggest that older adults may be particularly susceptible to the respiratory illness, which can cause pneumonia and symptoms like fever, cough and shortness of breath.

“The data coming out of China continues to say that the people who are at higher risk for severe disease and death are those who are older and with underlying health conditions,” said Nancy Messonnier, M.D., director of the National Center for Immunization and Respiratory Diseases, a division of the Centers for Disease Control and Prevention (CDC), at a press briefing on Monday.

Preliminary estimates suggest that the virus, which has so far sickened tens of thousands and resulted in hundreds of deaths, has a fatality rate of about 2 percent. Early findings from China, which pertained to the first 17 people to die in the outbreak, revealed that their median age was 75, and a recent study in the New England Journal of Medicine found that the median age of the first 425 people infected with the virus was 59.

This is typical of coronaviruses, a family that includes the viruses behind the SARS and ongoing MERS outbreaks as well as other respiratory viruses like the seasonal flu, says Vineet Menachery, an immunologist at the University of Texas Medical Branch who studies the effect of coronaviruses on aging immune systems.

“During the original SARS outbreak, the lethality rate for the overall number of cases was 10 percent, but that lethality rate jumped to over 50 percent in people over the age of 50,” he says.

Underlying conditions play a role

Menachery points to two main reasons for older adults’ increased susceptibility to coronaviruses. The first is that they are more likely to suffer from underlying conditions that hinder the body’s ability to cope with and recover from illness, such as chronic obstructive pulmonary disease.

“Age and your condition in life will really drive your susceptibility. You may be in your 40s, but if you have these chronic health conditions, you’re going to be more susceptible, just like you see with flu.” — immunologist Vineet Menachery, University of Texas Medical Branch

The second has to do with how our immune response changes with age, the exact mechanisms of which Menachery and other researchers are still working to fully understand. His work with coronaviruses has shown that older mice, for instance, experience more inflammation early on in the course of illness, perhaps “setting the table” for lung damage that can’t later be overcome (this novel coronavirus, like the ones responsible for SARS and MERS, affects the part of the lungs where gas exchange — the delivery of oxygen to the bloodstream and the removal of carbon dioxide — takes place).

“As you get older your lungs are not as elastic or as resilient as when you’re younger. Those kinds of things, coupled with any kind of health issue you might have, trend toward this loss of airway function and respiratory function.”

But, Menachery points out, this doesn’t mean that turning 65 — considered the starting point of older adulthood by the CDC and other organizations — automatically puts someone in the high-risk category. “Age and your condition in life will really drive your susceptibility,” he says. “You may be in your 40s, but if you have these chronic health conditions, you’re going to be more susceptible, just like you see with flu.”

Scientists are working to develop targeted treatments for 2019-nCoV. In the meantime, U.S. health officials recommend that people halt all nonessential travel to China and practice preventive hygiene measures, including thorough handwashing with soap and water.

The overall risk to the U.S. public remains low, the CDC’s Messonnier said Monday. “The focus right now,” she said, “is on travelers returning from places where this disease rate is soaring.”

Menachery also notes that the emergence of 2019-nCoV has overlapped with that of another potentially fatal respiratory illness: the flu, which remains at elevated levels across much of the country and has affected an estimated 19 million people so far this season, resulting in at least 180,000 hospitalizations (the majority of them among those 65 and older) and 10,000 deaths.

“It’s not too late to get your flu shot,” he says. “It’s actually been a really bad flu year.”

This article has been provided by AARP on 2/5/20. Click here for their article.