There is a known bias toward oversimplification. We like to distill complex situations down to a number, or a simple dichotomy. It allows us to mentally manage a complex world. The risk, of course, is that important details will be lost. In medicine that bias is hopefully beaten out of us by training and experience. We learn to embrace the complexity, but still we must be vigilant.
When evaluating the COVID-19 pandemic, reporting has focused almost exclusively on two numbers – the numbers of cases and the number of deaths. Many news outlets explicitly track those two numbers, with graphs and statistics. It has been a useful marker to follow the course of the pandemic. But that should not lull us into thinking these two numbers are all that matter when evaluating the total burden of this pandemic. Now that we have had more than a year of experience with COVID-19 researchers are increasingly tracking morbidity from the disease – health effects in those who survived. In short, death is not the only negative health outcome from contracting COVID.
A recent study published in PM&R looked patient records for those discharged from hospital between March and April 2020. Arguably, medical care improved throughout the pandemic as doctors gained more experience and research provided new tools. The case-fatality rate decreased over time. More updated numbers would therefore be interesting, but this does give us a glimpse at the potential morbidity of COVID. They found:
Nearly twenty percent of COVID-19 survivors discharged to a location other than their home. Forty-five percent of survivors experienced functional decline impacting their discharge. Eighty-seven (80.6%) of survivors who showed functional change during hospitalization were referred for additional therapy at discharge.
Nearly half of patients had a functional decline from their baseline. As many of these patients were older, especially early on in the pandemic, recovery was likely slow and incomplete. Another recent study published in BMJ Open looked at so-called “long COVID” – following patients for an average of 12.8 weeks after diagnosis. They found:
81.1% (596/735) reported pain and discomfort, 79.5% (584/735) problems with usual activities, 68.7% (505/735) anxiety and depression and 56.2% (413/735) problems with mobility.
This is an enormous burden, and the study documents that this affects not only the patients but their families and caregivers.
Anecdotally, as a neurologist who does not care for acute COVID illness itself but is referred patients with neurological complications and symptoms, I started seeing patients with neurological symptoms following COVID about six months into the pandemic. These numbers have steadily increased. Common complications include chronic headache and fatigue, mental fogginess, and chronic pain.
The numbers above and my experience are consistent with other published data. An Italian study, for example, found that 44% of patients had chronic symptoms of “fatigue, shortness of breath, joint pain, and chest pain, in that order”. Symptoms last for weeks or months after initial infection, and long after symptoms of acute illness, like fever, have resolved.
As we have learned more about COVID-19 these long term symptoms make sense. Originally we thought of COVID as a respiratory illness, because it presents with fever and cough. But in reality we have learned that it is also, or perhaps more so, a vascular illness. SARS-CoV-2 gets entry into cells by binding its spike protein to the ACE2 receptor – but these receptors are not found only on respiratory cells, they are widely distributed throughout the body and in many organs. This creates the potential for widespread effects of the infection, but the vascular effects appear to be dominant.
The virus attaches to blood vessels that line various organs and will also cause widespread inflammation and blood clots. The more severe the illness, of course, the more severe these effects can be, and the greater the morbidity. But even people with mild disease can have lingering symptoms.
There are at least 167 million cases of COVID so far worldwide, 33 million in the US. The health burden of long COVID is therefore potentially huge. When calculating the health cost of this pandemic, we cannot only count lives lost but also the reduce health of survivors. The death rate itself is staggering – almost 3.5 million worldwide and almost 600k in the US. This is not a “bad flu” even if just looking at the mortality numbers. But when we add the long COVID cases, the true size of the health burden becomes clearer.
This is an important point to drive home as we also, individually and collectively, calculate the risk vs. benefit of the various COVID vaccines. The vaccines currently being distributed have been proven safe and effective. As a public health measure, they are a clear home-run – extremely cost effective. When we add the emerging burden of long COVID or post-COVID disability, the benefits are even greater.
COVID morbidity needs to be part of any conversation about the risk and cost vs. benefit of any measures we contemplate to mitigate this pandemic.