When might COVID-19 become "endemic?"
That is to say, when will we reach the time when outbreaks will be more modest and manageable? That juncture has been described as when the virus has become "annoying but rarely deadly or disruptive."
Many observers cite influenza, the "flu," as an example of an endemic infectious disease. From 2012 to 2019, the flu virus annually caused approximately 31 million symptomatic illnesses, 400,000 hospitalizations, and 39,000 deaths in the United States, according to government statistics . Those high numbers are in spite of moderately good vaccines, with efficacy in the range of 40-60%, that need to be administered each year.
But our society considers the flu manageable and acceptable. After all, we don't impose lockdowns, mask mandates, or widespread vaccine mandates during the annual flu outbreaks.
Of course, COVID-19 isn't the same as the flu. For one thing, there's the phenomenon of post-COVID-19 syndrome, or "long COVID-19." This is marked by signs or symptoms that persist for more than four weeks, and often much longer, after the diagnosis of infection. It's still too soon to know what percentage of the 100 million-plus people infected with the omicron variant will progress to long COVID-19, but if the incidence is anywhere near the 10-30% following alpha or delta infections, our healthcare system will face pressures in grappling with its effects.
The costs of the pandemic continue to be significant. On Jan. 22, about 158,000 COVID-19 patients were hospitalized nationwide, more than at any previous point in the pandemic and 24% higher than two weeks earlier. Compared to earlier variants, omicron-infected patients have substantially lower rates of hospitalization, admission to intensive care units, use of mechanical ventilation, and death, but its higher contagiousness and the vast numbers of infections have pushed up the absolute number of hospitalizations.
Omicron breakthrough infections among vaccinated people are at least five times more frequent than with delta, and omicron appears to infect children more than previous strains. Many hospitals, particularly their emergency rooms and ICUs, have been pushed to the breaking point, and overburdened and burned-out healthcare workers are quitting in record numbers.
Still, pandemics do end eventually.
The Spanish flu of 1918-20 is thought to have killed 50 million to 100 million people worldwide, including an estimated 675,000 Americans — at a time when the U.S. population was only about a third as large as it is today. But the virus eventually became unable to find many new targets, the pandemic subsided, and the flu became the endemic, seasonal infection it is today.
We must keep in mind that every COVID-19 infection results in viral replication, the creation of new mutants, and the opportunity for Darwinian evolution to test them for "fitness" — that is, for greater transmissibility and ability to evade immune defenses. There is thus a risk that omicron won't get us to endemic status.
So, for now, the most prudent course is still to get vaccinated, boosted, and take other reasonable precautions.
Henry I. Miller, a physician and molecular biologist, is a senior fellow at the Pacific Research Institute and the former founding director of the Food and Drug Administration's Office of Biotechnology. He is the co-discoverer of a critical enzyme in the influenza virus.