I was much too young to appreciate Jonas Salk’s brilliance when Mom brought me to Dr. Peluso in October 1955 for my first polio vaccination, but I suspect she and Dad breathed a sigh of relief. Like most folks, they had watched cases rise dramatically after World War II, reaching a peak of 52,000 in 1952, and I can imagine them waiting anxiously for the arrival of a vaccine that would protect me and my two older brothers.
Now, nearly 65 years later, an even deadlier pandemic has again raised expectations that the most vulnerable among us might someday be delivered from harm by a miracle serum. I’m not holding my breath. And, to be completely honest, I’m not sure I’d roll up my sleeve.
Any geezer who’s suffered through a nasty case of influenza despite opting for the seasonal vaccine will tell you that it’s a crapshoot. Sometimes it works, sometimes not so much. I ignore all the dire warnings every fall and have always managed to keep the bug at bay. Maybe my immune system fends it off each year courtesy of my slapdash exercise regimen, a mostly healthy diet, plenty of sleep, and a stress-fighting meditation practice. Or maybe it’s just dumb luck.
As Jonathan Wosen notes in the Washington Post, the 2018–2019 flu shot effectively prevented the virus in about three of five children, but only one of four people over 50. That’s partly due to the fact that scientists can only guess at the particular strain that’s mobilizing to attack us each year, but it’s mostly about the inefficiency of the aging immune system.
And any coronavirus vaccine will probably perform similarly, University of Pennsylvania immunologist Michael Cancro, PhD, tells Wosen. “I doubt it will be worse; I don’t think it will be better.”
Young bodies respond to an effective vaccine by alerting an army of B cells that seek out invading pathogens and mark them for destruction by T cells. By the time we join the Medicare set, however, those B cells have lost some of their tactical precision. The antibodies they produce become less fine-tuned, allowing some infected cells to escape detection. We’ve also been losing T cells since our 20s, when our bodies stopped producing new ones, so even if our B cells could locate every offending pathogenic cell, we wouldn’t be able to marshal the artillery needed to eradicate them.
This also explains why folks my age are often laid low by viruses we encounter for the first time. We do harbor so-called memory cells that spring into action when a familiar pathogen (in my case, measles, mumps, and chickenpox, which I contracted as a child) enters the body, but they’re less functional as we grow older — and less effective against the rapidly mutating strains of the virus we encounter every flu season.
“We still don’t exactly understand why the heck that is,” says Cancro, “but it’s a fact.”
Amid all this uncertainty, Cancro points to a few hopeful signs. Researchers have, in fact, been able to improve the efficacy of the flu vaccine in the elderly by developing a higher-dose version that boosts antibody and T-cell response. And they’ve upgraded the shingles vaccine in recent years by strengthening T-cell memory. It’s now about 90 percent effective against the virus among people over 70.
“We’re seeing more imagination in the way we formulate vaccines,” Cancro explains, “either in terms of mimicking what a pathogen looks like or providing molecules that drive immune cells.”
I suspect researchers will need all the creativity they can muster to wrestle the novel coronavirus into submission. And, if that virus behaves anything like the seasonal flu bug, the battle will rage for generations to come. Meanwhile, I’ll continue to keep my distance from people, don my mask when necessary, and hope for the best. That doesn’t mean I won’t be rooting for the next Jonas Salk; an effective vaccine could save millions of lives. But I may need some convincing before I accept the notion that it could save mine.