We have no previous experience with a worldwide coronavirus pandemic, so when Sars-CoV-2, the virus that causes Covid-19, began spreading, public health experts leaned on our experiences with influenza pandemics to inform their predictions. These pandemics are often described in terms of “waves” and “troughs”. We have now seen enough to replace the ocean analogy with a better one: wildfire.
Like a wildfire, the virus relentlessly seeks out fuel (human hosts), devastating some areas while sparing others. It will continue spreading until we achieve sufficient herd immunity – when 50 to 70% of the population has developed protective antibodies – to significantly slow transmission. We will achieve herd immunity either through widespread infection or an effective and widely available vaccine. No amount of official happy talk will change that course.
We now have compelling evidence that Sars-CoV-2 is not affected by seasonality or regional weather; it spreads by the human contact and mixing that occurs in areas of high population density. We don’t yet know whether immunity is permanent or short-lived. We also don’t know if a vaccine, if and when we develop one, will be a bull’s-eye success like the vaccines for polio or measles, or more of a hope-for-the-best agent like seasonal flu vaccine. We hope vaccine development efforts will prove effective, but hope is not a strategy. Like HIV, Sars-Cov-2 is here to stay, and realism must inform our strategic response.
Studies of previous pandemics, wars and other times of intense national stress show that people react most calmly and effectively when leadership tells them the truth, even if that truth is frightening. If you don’t have answers, say so; tell the public what you’re doing to learn more. So far, the United States has largely seen the opposite approach: moving-target messaging that is often scientifically erroneous, irrationally optimistic and leaves the public in desperate confusion over who and what to believe, with science the first casualty. We must focus our message on scientific facts.
In the coming months, US morbidity and mortality will largely depend on how much fuel the Covid-19 wildfire has access to. While a full, Wuhan-style lockdown is impractical, we need to get as close as we can in hotspots of dangerously increasing case counts, suspending all but strictly essential services, to get transmission down to a manageable level. This is an extremely delicate balancing act, since so many functions are necessary to keep society going. Yet areas that observed tight shelter-in-place constraints, like New York and some countries in Asia and Europe, showed that we can bring the deadly numbers down and bring back the economy in a safer public environment.
Unfortunately, the US has often been far too optimistic and cavalier: at the first signs of effectiveness against Covid-19, we exhaled and concluded that we were “over the hump”, even when the case count exceeded 20,000 a day. We told ourselves that the curve had been flattened and business as usual could resume. The grim statistics, however, speak for themselves.
We must bring the infection rate down to a level where testing results are rapid enough that follow-up tracing can actually identify contacts in time to halt further transmission. Since the virus made landfall we have failed to do so. The level we need to reach is around two Sars-Cov-2 cases a day for each 100,000 population in a region. We’re nowhere near that right now, and the most pressing question ought to be what we have to do to change that. If we don’t have the fortitude and collective will to undertake and sustain the level of shutdown that will be necessary in large parts of the US, as well as the flexibility to react quickly and decisively when and where the virus flares, the number of new cases and deaths could be staggering, far beyond what we have experienced thus far.
We don’t expect this to be instituted on a national level by the current leadership. But governors on the frontlines understand the economic, social and political crises this virus is causing, not least the illness and deaths. It will therefore fall to them to decide whether to maintain the status quo and watch the number of cases continue to explode, or administer the more aggressive public health measures needed to not only treat cases but prevent spread.
The US has historically been a leader in epidemiology and public health, but now we must look to the example of countries such as South Korea and Singapore and certain EU nations, as well as states like New York, which recognized the challenge earlier; provided honest, effective leadership; and quickly undertook mitigation, testing and contract tracing.
We know that strategic lockdown causes great economic and social pain, and we must be prepared to continue taking care of those who suffer as a result, whatever the price. There are no foolproof or easy answers, and even nations that were initially successful in containment are facing renewed spread as their economies reopen.
But of one thing we can be certain: the cost of not acting will far exceed the cost of our second chance to get this right. And we may not have the luxury of a third.