Pandemic prediction is hard to do.
That’s one of the lessons to be taken from Covid-19. Unlike the weather, which depends largely on physical factors (I’ll leave climate change out of this for now), the surge and ebb of Covid-19 depends on biological and human factors.
There are three main axes of pandemic prediction: the virus, immunity, and human adaptation. These axes map out a large potential space, the contours of which will vary from community to community — geographically, demographically, and socially.
Yet there is one prediction I feel confident in making now: U.S. hospitals are not ready for the new normal.
Axis one: the virus
One axis of pandemic prediction is the behavior of the virus itself. In the best-case scenario, SARS-CoV-2 evolves slowly but gradually. New variants emerge every few years, and they’re less transmissible, less able to evade the immune system, and less virulent. A less-transmissible and less-immune-evading variant would mean fewer people infected. People infected with less virulent variants would be less likely to land in the hospital, and if hospitalized, would likely spend less time there and be less likely to die.
In the worst-case scenario, SARS-CoV-2 evolves in leaps and bounds. New variants are more transmissible and better at evading the immune system, so many people are infected, much as we’ve seen during the Omicron wave. Worse yet would be a variant that’s not only highly infectious and immune evading, like Omicron, but also more virulent, like Delta.
Before Omicron emerged, some opined that the virus had reached peak fitness — a point at which it no longer mutates to become more infectious. But with more than 50 mutations, Omicron made it clear that the virus still has plenty room to evolve.
SARS-CoV-2 will likely do some of both — mutate gradually and in leaps and bounds — resulting in the emergence of new disruptive variants anywhere from yearly to every few years. In years when the virus has mutated slowly, a seasonal pattern — with most cases around the winter holidays — is likely to be seen. A viral leap year could lead to out-of-season surges.
Axis two: the human immune system
The second axis is immunity to the virus. In the best-case scenario, 85% to 90% of Americans get vaccinated. Both vaccination and infection yield robust and durable immunity against severe disease, hospitalization, and death. The virus mutates more gradually and exposure to emerging variants boosts prior immune responses rather than evades them.
In the best-case scenario, skin microarray vaccines will be developed that elicit stronger antibody responses and better cellular immune responses, require less frequent dosing, and are easier to deliver. Companies will create effective mucosal vaccines which, when combined with injectable vaccines, provide better protection against infection. And best yet, vaccines emerge with the power to protect people against not just all SARS-CoV-2 variants but also against the original SARS virus and other animal coronaviruses that have the potential to cause disease in humans.
Combine those advances with making sure the rest of the world has equitable access to vaccines and treatment for immunocompromising conditions like HIV, and the world will have done a better job of reducing the rate at which new SARS-CoV-2 variants emerge.
In the worst-case scenario, Covid vaccination rates never surpass two-thirds of the U.S. population, and vaccination rates could even decline if efforts lag to vaccinate newborns, those who become at high risk as they age or develop new medical conditions, and immigrants. Vaccination rates in low-income countries languish, providing fertile ground for new variants. The immune system’s “memory” after vaccination and infection is too short lived or too narrow to protect against emerging variants. Worse yet would be if infection with one variant patterns the immune response in such a way that it has difficulty recognizing future variants.
Axis three: human adaptation
The third axis is human adaptation: How well do humans prepare for the best- and worst-case scenarios the virus and our immune systems deal us?
I believe that SARS-CoV-2 will become the worst of the winter viral respiratory infections. At the low end — in years when Covid behaves more like the seasonal flu — it could kill at least as many as seasonal influenza, with an average of 30,000 to 50,000 deaths per year in the U.S. alone. At the high end — when a new variant disrupts the fragile detente between the virus and population immunity — we’re unlikely to see more than the 450,000 Covid-19 deaths that occurred in 2021, but in a typical year 100,000 deaths from Covid-19 would be in the ballpark.
To be sure, that’s a wide range. How high hospitalizations and deaths climb will depend on us as individuals and collectively. This axis is clearly under human control: whether individuals wear N95 masks during Covid season and use rapid tests before social events or travel; whether the government and private sector partner to make Covid tests and treatment widely available and accessible or upgrade indoor ventilation and air filtration; and whether state and local governments, schools, and the private sector impose vaccination requirements.
Current trends suggest that these actions won’t happen. People are “done with Covid.” They’re focused on “the urgency of normal.” Getting back to normal now is what’s urgent for most people, not preparing for the future.
That approach — public health attention deficit disorder — has been the pattern with public health crises in the past. Americans focus, rally, and surge funding for public health for a short time and then, when many have lost interest or feel safe enough, the nation moves on. It’s the story of tuberculosis, HIV, flesh eating and other antibiotic resistant bacteria, and Ebola.
But we’re moving on, yet again, without having taken long-term steps to prepare for the next surge, which is sure to come. The country has fewer doctors, nurses, and other health care providers in hospitals now than at the start of the pandemic. Turnover is high. Health care workers are increasingly going to the highest bidder. As travelers, they can make more working fewer hours, so some choose to work less. And health care workers are also getting exposed and infected with SARS-CoV-2, which means time away from work.
Covid-19 and hospitals
Hospitals are contending with critical staffing shortages, less institutional memory, and lower morale to band together and fight the next surge. The good will of health care workers that has gotten the country through the past two years is drying up. Health care workers are also “done” — done with having our sense of duty and commitment to patient care taken for granted.
This is layered atop a fragmented health care system. Former Governor Andrew Cuomo’s vision of a single state hospital system never materialized in New York, and the rest of the country never even aspired to anything like that. Wealthier hospitals with the capacity to take patients from safety net and rural hospitals crushed by Covid aren’t incentivized to do so. It makes more sense for them to keep more lucrative elective surgeries and other procedures going.
Without efforts to better control Covid-19 in the future, some hospitals will shoulder a disproportionate burden of Covid care. When hospitals are overwhelmed and understaffed, deaths from Covid shoot up, and other medical care suffers, too. A pause on non-Covid care at some hospitals may become the new normal.
The U.S. will have to choose to deal with Covid-19 on the front end or the back end. There’s a lot more that can be done to prevent transmission and mitigate disease without shutting down society or the economy. But I fear that we will default to business as usual, leaving it for the American health care system to treat what could have been prevented. And, as usual, this system will do what it does best: provide care expensively, inequitably, and with underwhelming results.
Céline Gounder is an internist, infectious disease specialist, and epidemiologist; a senior fellow and editor-at-large for public health at the Kaiser Family Foundation’s Kaiser Health News; and host of the “American Diagnosis” and “Epidemic” podcasts.
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