The goal of the study be researchers at Harvard’s School of Public Health was to look at the spread of the virus over the next five years under different scenarios. What they found is that in order to reach herd immunity, where a majority of people have had the virus and built up some immunity to it, without overtaxing our health system, we may need to keep this up for a couple of years.

A modeling study on the new coronavirus warns that intermittent periods of social distancing may need to persist into 2022 in the United States to keep the surge of people severely sickened by Covid-19 from overwhelming the health care system.

The research, published Tuesday in the journal Science, looked at a range of scenarios for how the SARS-CoV-2 virus will spread over the next five years. Those scenarios included variables like whether people who are infected develop short-term immunity — less than a year — or longer-term protection. But, overall, the research concludes it is unlikely that life will return any time soon to the way it was before the virus’ emergence.

What the study suggests is that the social distancing may need to be turned on whenever outbreaks reach a certain critical level to prevent overwhelming the system and then relaxed when it drops again. Each time we reopen for business, the virus is going to begin spreading again and we’ll soon need to ramp up social distancing again if we want to avoid overwhelming the system. This pattern may have to repeat several times over the next couple of years.

How many times and how often will depend on a lot of factors that we don’t fully understand yet, including how long immunity to the virus lasts in the average person. If the immunity is short, say a few months, then people could be reinfected a year later, making it likely this becomes a new seasonal infection.

If on the other hand immunity is permanent, then we’ll eventually develop heard immunity as everyone is exposed. In fact, the study even mentions one rosy scenario where the new coronavirus is not only is eliminated in five years but because of cross-immunizes to less serious coronaviruses, we all become immune to the common cold as well. Wouldn’t that be nice. But if that rosy scenario doesn’t happen, we’ll probably be fighting this on and off for years. Here’s a graph from the study which shows how this could look under various scenarios. It’s basically the roller-coaster from hell for the world economy. The shaded blue regions are when we turn social distancing back on as the virus spreads.

Here’s the bottom line from the study’s discussion section which notes that the authors are well aware that what they are describing could spell economic disaster:

In summary, the total incidence of COVID-19 illness over the next five years will depend critically upon whether or not it enters into regular circulation after the initial pandemic wave, which in turn depends primarily upon the duration of immunity that SARS-CoV-2 infection imparts…Social distancing strategies could reduce the extent to which SARS-CoV-2 infections strain health care systems…Intermittent distancing may be required into 2022 unless critical care capacity is increased substantially or a treatment or vaccine becomes available. The authors are aware that prolonged distancing, even if intermittent, is likely to have profoundly negative economic, social, and educational consequences. Our goal in modeling such policies is not to endorse them but to identify likely trajectories of the epidemic under alternative approaches, identify complementary interventions such as expanding ICU capacity and identifying treatments to reduce ICU demand, and to spur innovative ideas to expand the list of options to bring the pandemic under long-term control. Our model presents a variety of scenarios intended to anticipate possible SARS-CoV-2 transmission dynamics under specific assumptions. We do not take a position on the advisability of these scenarios given the economic burden that sustained distancing may impose, but we note the potentially catastrophic burden on the healthcare system that is predicted if distancing is poorly effective and/or not sustained for long enough.

In short, we have two terrible possibilities before us. One is killing the economy with repeated shutdowns. The other is overwhelming the hospitals with a glut of very ill people. At least that could be the case. The final word from this study is that we just don’t know enough to say how things will play out until we know a) how many people have actually been infected so far and b) how long their immunity to this lasts after they recover.

Longitudinal serological studies are urgently required to determine the extent and duration of immunity to SARS-CoV-2, and epidemiological surveillance should be maintained in the coming years to anticipate the possibility of resurgence.

But the worrisome message is that it’s possible no matter what choices we make, we will find ourselves dealing with the impact of this virus for years to come.