Are Seniors Prone to COVID -19, because of Weakened Immune Systems?

Are Seniors Prone to COVID -19? According to the CDC, eight out of every 10 COVID-19 deaths in the U.S. have been in adults age 65 and older. This age group also accounts for nearly 70% of all coronavirus hospitalizations nationwide.

That’s because the prevalence of underlying health conditions, like diabetes and heart disease, as we grow older plays a critical role. However, the experts at the Oklahoma Medical Research Foundation contend that there’s another answer for part of the blame: our immune system, the biological network whose job is to protect us against foreign invaders like viruses. That’s from The Oklahoman’s recent article entitled, “Weakened immune system leaves elderly prone to the virus.”

“The general line of thinking is that immunity falters with normal aging, just like our muscle mass and cognitive function,” said Dr. Hal Scofield, a physician-scientist at Oklahoma Medical Research Foundation. “You don’t see pro athletes playing after age 50. We have a shelf life physically, and that goes for immunity, too.”

That decreasing immunity means that the elderly are more prone to serious complications not only from COVID-19 but also from seasonal illnesses, such as the flu.

T cells and B cells, special types of white blood cells involved in the immune response, offer clues to why immunity declines with age, according to OMRF immunologist Susan Kovats, Ph.D. “We don’t know all the specifics behind the decline in immune function with aging, but we do know that both T cell and B cell function deteriorates with age,” she said.

T cells are created by a small organ in your chest called the thymus, “which slowly shrinks over time and is essentially gone in your adult years,” said Kovats.

Meanwhile, the ability of B cells to produce highly specific antibodies that inactivate viruses also drops as we get older. B cell numbers decline to a greater extent in elderly men, Kovats said. This may explain why they are more apt to die from severe COVID-19 disease. These age-related declines explain why, for example, a virus like shingles is more likely to appear from a weakened immune system later in life.

“If you’ve had chickenpox, the shingles virus stays in your body forever,” said Dr. Scofield, who also serves as associate chief of staff for research at the Oklahoma City VA. “When you’re young, your immune system keeps the virus in check. As you age, your body begins to lose its defenses and that increases your likelihood of getting shingles.”

The weakened immunity that is seen in the elderly has also made the annual flu shot less effective for that age group. The CDC reports that just 25% of people age 50 and older were protected during the 2018-19 flu season.

“The immune responses to vaccines are not as good overall in the elderly, and this is a legitimate concern as COVID-19 vaccines are hurried to the finish line,” said Kovats. “A lot of work is being done to try to understand why the immune response weakens, and significant effort has gone into changing how vaccines are made for this age group, in order to solicit better immune responses.”

Because seniors are prone to Covid, researchers at Oklahoma Medical Research Foundation and across the U.S. are investigating the mysteries of aging, as well as the immune system, to better protect a population that now has over 50 million Americans over the age of 65.

“COVID-19 is unlike anything the body has ever seen before, and older people do not respond well to pathogens or viruses they’ve never been exposed to,” Scofield said. “This is going to be a challenge, but the more we learn about how the immune system works, the better we’ll be at protecting our seniors in future outbreaks.”

Reference: The Oklahoman (June 2, 2020) “Weakened immune system leaves elderly prone to the virus”