Racing against the clock: Fight against corona worse than the disease

We routinely differentiate between two kinds of military action: the inevitable carnage and collateral damage of diffuse hostilities, and the precision of a “surgical strike,” methodically targeted to the sources of our particular peril. The latter, when executed well, minimises resources and unintended consequences alike.

As we battle the coronavirus pandemic, and heads of state declare that we are “at war” with this contagion, the same dichotomy applies. This can be open war, with all the fallout that portends, or it could be something more surgical. The US and much of the world so far have gone in for the former. I write now to make sure we consider the surgical approach, while there is still time.

Outbreaks tend to be isolated when pathogens move through water or food, and of greater scope when they travel by widespread vectors like fleas, mosquitoes or the air itself. Like the coronavirus pandemic, the infamous flu pandemic of 1918 was caused by viral particles transmitted by coughing and sneezing. Pandemics occur when an entire population is vulnerable to a given pathogen capable of efficiently spreading itself.

Immunity occurs when our immune system has developed antibodies against a germ, either naturally or as a result of a vaccine, and is fully prepared should exposure recur. The immune system response is so robust that the invading germ is eradicated before symptomatic disease can develop.

Importantly, that robust immune response also prevents transmission. If a germ can’t secure its hold on your body, your body no longer serves as a vector to send it forward to the next potential host. This is true even if that next person is not yet immune. When enough of us represent such “dead ends” for viral transmission, spread through the population is blunted, and eventually terminated. This is called herd immunity. What we know so far about the coronavirus makes it a unique case for the potential application of a “herd immunity” approach, a strategy viewed as a desirable side effect in the Netherlands, and briefly considered in the UK.

The data from South Korea, where tracking the coronavirus has been by far the best to date, indicate that as much as 99 percent of active cases in the general population are “mild” and do not require specific medical treatment. The small percentage of cases that do require such services are highly concentrated among those age 60 and older, and further so the older people are. Other things being equal, those over age 70 appear at three times the mortality risk as those aged 60 to 69, and those over age 80 at nearly twice the mortality risk of those aged 70 to 79.

These conclusions are corroborated by the data from Wuhan, China, which show a higher death rate, but an almost identical distribution. The higher death rate in China may be real, but is perhaps a result of less widespread testing. South Korea promptly, and uniquely, started testing the apparently healthy population at large, finding the mild and asymptomatic cases of COVID-19 other countries are overlooking. The experience of the Diamond Princess cruise ship, which houses a contained, older population, proves the point. The death rate among that insular and uniformly exposed population is roughly 1 percent. We have, to date, fewer than 200 deaths (updated since) from the coronavirus in the US — a small data set from which to draw big conclusions. Still, it is entirely aligned with the data from other countries. The deaths have been mainly clustered among the elderly, those with significant chronic illnesses such as diabetes and heart disease, and those in both groups.

This is not true of infectious scourges such as influenza. The flu hits the elderly and chronically ill hard, too, but it also kills children. Trying to create herd immunity among those most likely to recover from infection while also isolating the young and the old is daunting, to say the least. How does one allow exposure and immunity to develop in parents, without exposing their young children?

The clustering of complications and death from COVID-19 among the elderly and chronically ill, but not children (there have been only very rare deaths in children), suggests that we could achieve the crucial goals of social distancing — saving lives and not overwhelming our medical system — by preferentially protecting the medically frail and those over age 60, and in particular those over 70 and 80, from exposure.

We could focus our resources on testing and protecting, in every way possible, all those people the data indicate are especially vulnerable to severe infection: the elderly, people with chronic diseases and the immunologically compromised. Those that test positive could be the first to receive the first approved antivirals. The majority, testing negative, could benefit from every resource we have to shield them from exposure.

There are several major problems with subsuming the especially vulnerable within the policies now applied to all. First, the medical system is being overwhelmed by those in the lower-risk group seeking its resources, limiting its capacity to direct them to those at greatest need. Second, health professionals are burdened not just with work demands, but also with family demands as schools, colleges and businesses are shuttered. Third, sending everyone home to huddle together increases mingling across generations that will expose the most vulnerable.

So long as we were protecting the truly vulnerable, a sense of calm could be restored to society. Just as important, society as a whole could develop natural herd immunity to the virus. The vast majority of people would develop mild coronavirus infections, while medical resources could focus on those who fell critically ill. Once the wider population had been exposed and, if infected, had recovered and gained natural immunity, the risk to the most vulnerable would fall dramatically.

A pivot right now from trying to protect all people to focusing on the most vulnerable remains entirely plausible. With each passing day, however, it becomes more difficult. The path we are on may well lead to uncontained viral contagion and monumental collateral damage to our society and economy. A more surgical approach is what we need.