A recent review of past infectious epidemics suggests that a subgroup of COVID-19 survivors may suffer from chronic post-viral complications, including ME/CFS.
There is still much we do not know about the novel coronavirus, COVID-19, but it is becoming clear that many survivors of the initial infection are now reporting longer term, post-viral complications, including fatigue, muscle pain and sore throat.
Many people experience post-viral fatigue and other complications after an infection, but these are usually short-lived and resolve within a few days or weeks. However, for some people these complications last much longer and may have a significant impact on the quality of their life. In fact, an infection is commonly reported as a trigger for the development of ME/CFS.
A recent article in the journal, Fatigue: Biomedicine, Health & Behavior, explores the experiences of past epidemics, and asks what these can tell us about the potential risk of developing post-viral fatigue and/or ME/CFS following COVID-19.
A review of follow-up studies looking at past viral epidemics and non-viral outbreaks (including SARS-CoV, the 2009 H1N1 pandemic, ebolavirus, Lyme disease and the 1918 Spanish flu), reveals that many of these have been linked with the development of long-term fatigue and complications such as muscle/joint pain, headaches and sore throat.
In one study, four years after the SARS outbreak in Hong Kong, 46% of individuals who reported post-viral complications were suffering from chronic fatigue, while 27% met the CDC-1994 criteria for a diagnosis of CFS. In addition, a study in Norway found that the H1N1 influenza pandemic resulted in a two-fold increased risk of developing ME/CFS.
And it is not just viral epidemics that are associated with chronic fatigue and the development of ME/CFS. An outbreak of Giardia lamblia, a microscopic parasite, in Norway was followed up two years later, when researchers found that 40% of affected people still reported chronic fatigue. Another follow-up study on the same outbreak found that a CFS diagnosis (based on the Fukuda criteria) was eight times more prevalent in affected individuals than in the general population.
It is worth noting, that one of the main drawbacks of these studies is that they were small and focused mainly on the prevalence of the symptom of chronic fatigue, rather than exclusively on ME/CFS.
However, based on the evidence from these past epidemics, it does seem likely that the COVID-19 pandemic will result in an increase in the number of people suffering with post-viral fatigue, a proportion of whom will go on to develop ME/CFS.
As we are still in the middle of the pandemic and much is yet unknown, it is hard to predict the extent of this increase in post-viral fatigue and ME/CFS. But we will continue to monitor the research landscape for any updates on COVID-19 and potential links to new cases of ME/CFS.