Understanding chronic Covid-19.

In their timely study, Hampshire and colleagues show that chronic Covid-19 negatively effects cognitive ability, likening the decrease in ability to the age-related decline in cognition between 50 and 70 years of age. However, additional information on participant characteristics and severity of medical treatments may help with contextualising the study results. For instance, approximately 59% of participants were female, and according to Townsend and colleagues chronic fatigue following Covid-19 infection is more prevalent in females. Consequently, this may mean that cognitive decline may also be more prevalent in females or that cognitive decline may result from long-term fatigue following infection. Furthermore, about 35% of study participants were mechanically ventilated (MV) and this increases the risk of associated health concerns, especially in patients with comorbidities. Ibrahim and colleagues found a prevalence of complications from invasive MV in Covid-19 patients, and that the risk of complications increased when patients had existing health concerns such as obesity, hypertension, chronic renal or cardiac disease. Additionally, MV in animal studies has shown a propensity toward inducing neuroinflammation, neuronal damage, and cognitive impairment, all of which presumably may extinguish cognitive abilities. Therefore, the cognitive decline observed by Hampshire and colleagues may have been due to participant characteristics and/or be iatrogenic and a causal association of Covid-19 with the observed decline requires more thorough investigation into these, and potentially other, confounding variables.

Contributors

T.M. is the sole contributor.

Funding Sources

None to declare.

Declaration of interests

None to declare.