Long Covid is a persistent state of ill-health after Covid-19 infection, which can continue for more than three months, and cannot explained by an alternative diagnosis.
Patients with long Covid have reported experiencing different combinations of symptoms, including fatigue, shortness of breath, cough, anxiety, cognitive impairment or brain fog, and muscle pain. These symptoms often get worse after performing physical activities.
These symptoms could be driven by a direct effect from virus infection, and might be explained by several hypotheses, including abnormal immune response, hyperactivation of the immune system, or autoimmunity.
Additionally, indirect effects including reduced social contact, loneliness, incomplete recovery of physical health, and loss of employment could also lead to psychiatric symptoms.
The Covid-19 Long-Term Effects and Recovery (CLEAR) study team from the University of Malaya has conducted an online survey among Covid-19 survivors from July to September 2021, during the nationwide movement control order (MCO).
A total of 732 respondents participated in the survey. One in five Covid-19 survivors have reported experiencing long Covid. The most commonly reported symptoms were fatigue, brain fog, depression, anxiety, insomnia and joint or muscle pain.
Women have been found to have a 58 per cent higher chance of experiencing long Covid compared to men.
According to the autoimmune hypothesis, women have stronger immune responses than men, due to genetic and hormonal factors.
This contributes to a more active immune response, where activation of white blood cells and production of inflammatory markers and antibodies are stronger than in men.
This could be seen as a double-edged sword, as while it appears to confer better protection against severe symptoms and deaths, it could also bring about the emergence of autoimmune inflammatory symptoms that lead to long Covid.
Patients with moderate and severe levels of acute Covid-19 have 3 to 3.6 times chances of acquiring long Covid, compared to those without symptoms.
A point to note is that those without symptoms or with mild symptoms also reported experiencing long Covid (10 per cent and 17.5 per cent respectively), compared to those in the moderate (26.7 per cent) and severe (30.4 per cent) categories.
This may be explained by the immune response to the SARS-CoV-2 virus, which stimulates the production of cytokines and other inflammatory mediators, with higher concentrations found in those with more severe Covid-19 conditions.
The multi-systemic inflammatory response to the virus may also be responsible for persistent Covid-19 symptoms in survivors.
To avoid long Covid is to avoid Covid-19 infection.
We should all get vaccinated or boosted, and practise standard operating procedures such as mask wearing, social distancing, hand hygiene, avoiding crowded and poorly ventilated places, and finally, getting tested if there are symptoms.
Prof Dr Moy Foong Ming is from the Department of Social and Preventive Medicine, Faculty of Medicine, University of Malaya.
- This is the personal opinion of the writer or publication and does not necessarily represent the views of Ova.