The true course of the coronavirus epidemic, updated

By Kevin Roche

A few weeks ago I wrote a post summarizing what I believed the science and data was telling us about the nature of the coronavirus epidemic.  As research and data gathering continues apace, I thought it an apt time to update that post.

photo by Mircea Iancu

The epidemic almost certainly started by November in China, perhaps earlier, in October.  The Chinese clearly suppressed information about what was occurring.  By the time it became apparent that an epidemic of some severity was underway, thousands of people had traveled from areas where the virus was circulating to many countries across the globe.  Those people infected others in the countries to which they traveled, and until international travel ceased, there likely was a pattern of travel of infected persons from one country to another. There is accumulating evidence that the virus was in Europe as early as November.  It is almost certain that the virus was in the United States by December.  At least two deaths in early and mid-February in California are now attributed to coronavirus, which would suggest that infections must have been occurring well before the date of those deaths.

Although the Chinese probably realized this, it wasn’t apparent to other countries how differentially the virus affected people throughout the age spectrum, or that a large proportion of the population did not become infected on exposure or was asymptomatic.  Now we know the difference is quite extreme.  Given the typical social contact patterns of children, adults and the elderly, particularly the elderly in long-term care facilities and other group living settings, it would seem sensible to assume that the virus was infecting younger and working age people first and these people largely were asymptomatic or had mild illness that they believed was just a cold or the flu.  So while there likely were many infections, there were few serious illnesses, and there was little awareness that an epidemic was underway.  Since dying from coronavirus usually involves pneumonia or other respiratory distress not dissimilar to flu, even deaths would not have appeared to medical personnel to have been due to a new agent, until there was awareness of the potential spread of the disease from China.  In the United States, I believe it is reasonable to assume that we had a large number of infections, possibly even a number of deaths, in January and February, before the nursing home spread in Washington state alerted people to the potential seriousness of cases.  Transmission from travelers from both Asia and Europe was the likely source for multiple outbreaks across the country, and then intra-country travel further seeded transmission.

Early modeling, based on incomplete and inaccurate data from China, and terrible epidemiologic assumptions, gave wildly high case and death estimates and politicians failed to exercise leadership either in evaluating the models or in considering the harms of potential mitigation measures.  Among other issues, the models failed to consider that given the presence of common coronavirus strains which previously had infected many people, 100% of the population was unlikely to be susceptible, and that there would likely be significant variation in serious of illness.  Research is now confirming that many people do have cross-reactive immune protection, both from earlier coronavirus strain infections and general immune defenses.  The models have still not evolved to adequately account for these factors.

It would likely have taken a longer time for the virus to reach the elderly, who have fewer work and other contacts, and again, any initial illness might have been perceived as flu-linked.  But when it began to reach the elderly, especially in long-term care settings, the virus spread rapidly due to their lower ability to prevent infection and serious illness and the higher presence of other serious health conditions.  Early results in the US, because the known cases were heavily weighted toward the frail elderly and others with serious pre-existing conditions and because there was no detection of the many cases among the younger and healthier parts of the population, appeared to support the notion that a high proportion of all cases would be serious illnesses and there would be a high rate of death.  Instead of waiting for more clarity or considering other explanations, driven by public health experts who should have known better, governments began issuing stay-at-home and business shutdown orders.  We all now know what the result of those has been, with tens of millions of jobs lost, hundreds of thousands of small businesses destroyed, health harms and social unrest.

It couldn’t be more obvious from the data at this point that children have essentially zero risk and working age adults have a very, very small risk.  The frail elderly on the other hand, have a far, far higher risk.  So left unchecked, this epidemic would have assumed an almost bifurcated shape.  For the general population it would have been fairly similar to a bad flu year, almost all infected people would have no or mild disease.  For the at-risk sub-groups, especially the frail elderly, especially those residing in a group setting, it would have proceeded very quickly and caused a large number of deaths.  And even with extensive lockdowns, that is the shape it has and continues to assume.

The epidemic was also front-loaded, in the sense that the virus has most easily infected the most vulnerable and the initial outcomes in terms of hospitalizations and deaths look very bad.  At this point, it may have largely run through those most vulnerable populations in most states.  Even as we see more cases, there is a far lower proportion of serious illness.  We see a constantly declining percentage of cases with hospitalizations and deaths as the outcomes.  This is most clearly seen in the Worldometers percent of critical cases, which reflects hospitalizations.  That number was over 5% early on and has continually declined to be around 1.5% at this point. While some have suggested that the virus is becoming less lethal, the more accurate explanation is that it is only encountering individuals who are more capable of mounting an early and effective defense against infection and illness.

The obvious strategy, based on what we know now, and really have known since near the start of the epidemic, is focusing on protecting the at-risk groups while encouraging everyone else to go about their lives as normal.  In particular, children should be in school and doing normal social activities.  Working age adults who are healthy should be at work.  The current approach of excessive social distancing and continuing business and social life restrictions has interfered with the development of population immunity, which would slow the virus’ transmission to all groups.  These actions have actually created a longer and greater period of risk to the elderly.  Currently there is undue worry about an increasing number of cases, especially among younger people as more social and work interaction occurs.  This should be viewed as a good thing and we should not go too far in preventing it.  Large numbers of asymptomatic and mild cases move us ever closer toward population immunity.

We should have an active policy of encouraging population immunity; it is faster and more likely than development of a universal vaccine.  The vaccine advocates are over-selling the likelihood or need, and drug companies are of course salivating at all the money they will make.  It would be far less damaging to the economy and to our health to more quickly open up completely.  We are seeing a large number of excess deaths from both the joblessness we have created and from the terrorization of the population which has led many people to avoid needed medical care.  Stress and anxiety are widespread.  It is honestly hard to imagine a dumber response.  And if we don’t reverse course now, we are multiplying all the pain we feel–from the virus, from joblessness, from loss of social contact.