SARS-CoV-2, a type of coronavirus, and its disease COvID-19 is everywhere. With each passing day, more cases pop up across the globe and there is no country unaffected (Johns Hopkins global tracker). As we have increased testing in the US we are seeing an increasing number of asymptomatic cases. This is a troubling realization as we try to answer the question: when can we stop socially distancing and “reopen the country”?
Social distancing was meant to slow the virus. That’s an important point that many are quick to glance over. Social distancing measures were never meant to prevent infections, just reduce the number of current infections. Experiences of countries like Italy and Spain revealed overwhelming numbers of critically ill patients infected with coronavirus. Hospitals were at capacity, supplies of ventilators and protective equipment were depleted and entire cities resorted to severe screening criteria in order to qualify for the most critical resource, a hospital bed. These same areas, once completely overwhelmed, implemented rigid stay-at-home orders and curfews. But why? Certainly not because these measures have been shown to prevent illness. In order for that to be the case, far more knowledge of all infected patients and exact modes of transmission would be necessary.
These cities resorted to isolation measures to physically separate people and hopefully slow the transmission of the infection from one person to another. Slowing transmission allows for more time to treat the currently ill, and hopefully “catch up” with the overwhelming wave of critical patients. So why does this strategy not prevent illness? After all, if you slow it, less people are getting sick, which is prevention right? Not exactly.
Preventing an illness from taking hold of a patient requires one of two things: a vaccine against the illness, or a reliable and easily accessible method for diagnosing the illness in order to prevent an infected person from spreading it. Neither of these measures is available today for coronavirus (COVID-19). Then why are we socially distancing? Purely in an effort to prevent the simultaneous illness of most of the population.
Coronavirus has proven itself to be a formidable opponent. It is highly infectious, spreads quickly through a population, and can be transmitted by people with minimal symptoms. Think of children with one day of cough, young adults with an isolated sore throat, or a friend with “allergies” and some nasal congestion for a couple of days. All of these people could be infected with coronavirus but none of them would be tested in our current environment of limited capability. None of them are critically ill, and testing is a resource in short supply that should be reserved for those who need it most. In addition, the most common test is still wrong, giving a false negative about 30% of the time. What about when testing is more accessible and we can test everyone, should we?
Testing may answer the question “is this person infected”, assuming the test quality is good and false negatives are low. But does it matter? If there is no treatment and no vaccine, the only thing to do with someone who tests positive is to quarantine them. But, if there are large numbers of people who are infected with minimal or no symptoms walking around untested, what is the point? We would quarantine those with positive tests while many others would continue to spread the infection. Can we test every person in the USA ? And if we could, how many times would we need to test them? Weekly? A negative test today would not mean you would not become infected in a day or two. It’s a losing battle.
Then is it even possible to avoid becoming infected? We can not definitively say that everyone will eventually catch this illness, but there is a high likelihood that everyone will be exposed at some point. The only positive news in all of this has been that there appear to be many who become infected and recover without complication. In fact, South Korean numbers show the vast majority recover uneventfully.
Then why continue with social distancing? Remember that this method is intended only to prevent overwhelming current medical resources. In areas where this is not an issue, social distancing does not provide a proven benefit. Could the “at risk” population continue to isolate while the remainder return to normal activity? Sure. For how long? Perhaps long enough for the infection to spread through that area and for most to become immune. This is the “herd immunity” we see with vaccinations to other diseases. When a person has recovered from an infection or receives a vaccine, they become immune. The more people in a community who are immune and no longer spreading the virus, the safer it is for those at-risk since the chances of catching the disease are lower. This means that social distancing works against herd immunity. But recall that social distancing is not meant to prevent disease, only slow it. Is it wise for everyone to socially distance or isolate themselves indefinitely? Certainly not.
The only question left to answer is when to cease social distancing ? The answer to that question is likely to be regional, depending on the number of cases that have occurred and the number of people known to have been infected in that area. The more people in the area that have been infected and recovered, the better the herd immunity, making it safer for those at risk. Areas where infection rates are high and massive numbers of people are infected quickly, develop herd immunity more quickly. Areas where infection rates are small still have the potential to cause problems for at-risk populations. But all of this requires robust methods for testing and methods for determining those who already recovered with minimal or no symptoms, through antibody testing.
If we are likely to be exposed unless we remain isolated indefinitely but also in need of that exposure in order to develop herd immunity, then how do we move forward from here? The answer is a combination of several factors we discussed above.
- Preventing medical resources from becoming overwhelmed by social distancing (slowing the disease)
- Devoting resources to testing (who is sick?)
- Devoting resources to antibody tests (who has recovered without knowing they were sick?)
- Devoting resources to vaccine development.
- Easing social distancing in areas where hospitals still have capacity, in order to build herd immunity (and reduce the negative effects of distancing on society)