Myalgic Encephalomyelitis (ME) outbreaks can be modelled as an infectious disease: a mathematical reconsideration of the Royal Free Epidemic of 1955, by FG Waters, GJ McDonald, S Banks, RA Waters in Fatigue: Biomedicine, Health & Behavior, 22 July 2020 [doi.org/10.1080/21641846.2020.1793058]
Research abstract:
In 1970, two clinicians, McEvedy and Beard
[McEvedy CP, Beard AW (1970) Royal Free Epidemic of 1955: A Reconsideration The British Medical Journal 1: No. 5687: 7-11]
Royal Free Hospital former site
re-analysed some of the case notes, and hypothesised that the Royal Free outbreak was epidemic hysteria. This hypothesis was the beginning of an entrenched belief that the disease at the Royal Free, and similar cluster outbreaks, were psychosomatic. This was to have a profound effect on the interpretation of the same illness for nearly 50 years as a presumptive psychosomatic, an interpretation that has lasted nearly 50 years.
Methods
The 1927 Susceptible Infected Recovered (SIR) mathematical model
[Kermack WO, McKendrick AG. Contribution to the mathematical theory of epidemics. Proc Royal Soc London. 1927;772:701-721]
for the transmission of disease has been used to examine the published admission data from the Royal Free Hospital for the purpose of finding out if the disease had the characteristics of a contagious disease. Similar cluster outbreaks have also been modelled to assess whether they have similar characteristics to the Royal Free outbreak.
Results
Using the 1927 Susceptible Infected Recovered (SIR) model
[Kermack WO, McKendrick AG. Contribution to the mathematical theory of epidemics. Proc Royal Soc London. 1927;772:701-721]
for the transmission of disease, we show that the epidemic of a disease of an unknown aetiology at the Royal Free Hospital in 1955, and other similar twentieth-century outbreaks, have the characteristics of a communicable disease. The disease causing the Royal Free outbreak was given the name ‘Benign Myalgic Encephalomyelitis’ by Acheson
[A new clinical entity? Lancet. 1956;1:789-790]
in 1956, now identified as ME.
Conclusions
By showing that the Royal Free and other ME attributed outbreaks fit the SIR disease model, we demonstrate that the McEvedy and Beard hysteria hypothesis is mathematically incorrect. The ensuing management of the treatment of ME/CFS-like conditions evolving from that, now mathematically improbable belief may need to be re-evaluated.
4. Conclusions
By using the Susceptible Infected Recovered (SIR) model for the transmission of disease
and comparing actual and predicted admission data we show:
- The Royal Free cluster outbreak has the mathematical attributes of a contagious
disease. - The cluster outbreaks in Cumbria and Great Ormond Street appear to have the attribute of contagious diseases with similar infection indices (Beta) as the Royal Free.
- Furthermore, attempting to model a known hysteria outbreak in Kombolcha yielded no viable solution, and the limited results obtained in no way matched the results from modelling the ME cluster outbreaks.
Thus this work mathematically disproves the McEvedy–Beard hypothesis that the cluster outbreak at the Royal Free was due to mass hysteria.
