KUALA LUMPUR, May 17 – University of Malaya (UM) public health professor and epidemiologist Prof Dr Moy Foong Ming estimates that between 10 per cent and 20 per cent of people with Covid-19 in Malaysia experience long Covid.
This translates to between about 448,000 and 896,000 people nationwide with long Covid, out of some 4.5 million confirmed Covid-19 cases reported as of yesterday, including between 173,000 and 345,000 people with symptoms persisting beyond acute illness in the country’s commercial region of the Klang Valley.
She also said symptoms of long Covid and their duration may vary depending on a country’s vaccination coverage and the coronavirus variant a person was infected with.
Dr Moy, who led a long Covid study between July and September last year during the Delta variant wave, said another survey will be rolled out to “capture the change” in patterns of long Covid in the country.
“With vaccination uptake increased and with the Omicron variant being the dominant virus now, we think there may be some variation in the duration, symptoms experienced for long Covid,” Dr Moy told CodeBlue in a recent email interview.
Her views echo an unpublished study conducted by researchers at the University of Florence and Careggi University Hospital in Florence, Italy, which found a “substantial change” in the pattern of neurological and cognitive or emotional problems.
According to health news service MedicalXpress, the observational study of 428 patients between June 2020 and June 2021 found that when the Alpha variant was the dominant strain, the prevalence of myalgia (muscle aches and pain), insomnia, brain fog, anxiety or depression significantly increased, while anosmia (loss of smell), dysgeusia (difficulty in swallowing), and impaired hearing were less common.
This compared to patients infected between March and December 2020 when the original SARS-CoV-2 strain was dominant.
“Many of the symptoms reported in this study have been measured, but this is the first time they have been linked to different Covid-19 variants,” lead researcher Dr Michele Spinicci was quoted as saying.
The study was presented at the European Congress of Clinical Microbiology and Infectious Diseases last month.
Dr Moy said long Covid can be broadly divided into three categories: permanent organ damage, post intensive care unit (ICU) care syndrome, and symptoms that appear after recovery.
Patients in the “permanent organ damage” category refer to Covid survivors who do not recover completely and have ongoing symptoms because of direct damage from the virus.
Those in the “post ICU care syndrome” category have symptoms related to chronic hospitalisation. These patients may suffer from inherent muscle weakness, cognitive brain dysfunction, and psychosocial stress causing post-traumatic stress disorder-like syndrome.
For those with “symptoms after recovery”, symptoms that linger on are produced after recovery because of the interplay between inflammatory markers and the immune system.
“Based on the above, the first two groups are more severe and usually happen among patients from Categories Three to Five. These groups of patients usually are admitted to the hospitals during their acute Covid and given follow up appointments with Rehab Medicine after being discharged,” Dr Moy explained.
“Patients who are in Categories One and Two, and on home quarantine usually belong to the third group and may suffer long Covid in the milder form. However, these symptoms may also interfere with their work or daily life. So, those patients who are younger and suffer a milder form of acute Covid may be in this group,” Dr Moy said.
Dr Moy said long Covid patients from the “permanent organ damage” and “post-ICU care syndrome” categories are usually followed up by rehabilitation medicine clinics. Their treatments are more straightforward as these symptoms were already diagnosed when they were treated for acute Covid in the hospital.
However, long Covid patients who develop symptoms after recovery would be “more difficult to diagnose”, as their symptoms like fatigue, anxiety, brain fog or memory loss are not specific.
“Patients also may not know where to seek treatment. This group makes up the majority of the long Covid patients and they are not given adequate attention by the Ministry of Health (MOH). This group of patients can seek treatment from the primary care clinics or with general practitioners (GPs) in the private sector,” Dr Moy said.
The MOH previously estimated the prevalence of long Covid in Malaysia to be at about 10 to 15 per cent of people infected with Covid-19. However, the study led by Dr Moy suggests long Covid prevalence to be around 21 per cent of Covid-19 cases nationwide.
Health Minister Khairy Jamaluddin said in a statement last Tuesday that about 65 per cent of severe Covid-19 cases in Categories Four and Five experience long Covid post-recovery, but did not state the latest estimated prevalence for people infected with the coronavirus across severity of disease, including asymptomatic and mild infections.
“I think it is quite safe to estimate the prevalence of long Covid is about 10 to 20 per cent. For those with permanent organ damage, they don’t really recover. But for those who suffer fatigue, brain fog which are in milder form, from the feedback of some of my respondents, they do recover completely. However, we don’t have the exact statistics. More studies are needed,” Dr Moy said.
The initial long Covid survey by UM conducted during the Movement Control Order (MCO) period from July to September 2021, involving 732 respondents who survived Covid-19, found that women and people with severe Covid-19 have a higher chance of developing long Covid.
Women have been found to have a 58 per cent higher chance of experiencing long Covid compared to men, while 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.
Of the total 732 Covid-19 survivors, 21.1 per cent experienced long Covid symptoms, most commonly fatigue, brain fog, depression, anxiety, insomnia, arthralgia (joint stiffness), or myalgia.
Dr Moy said the higher prevalence of long Covid in women could be attributed to the autoimmune hypothesis, which suggests that 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, production of inflammatory markers and antibodies are stronger than males. This could be seen as a double-edged sword as it appears protective towards severe symptoms and deaths from Covid-19, but it could bring about the emergence of autoimmune inflammatory symptoms in long Covid,” Dr Moy said.
Respondents who had moderate to severe acute Covid-19 infection also had higher odds of experiencing long Covid at 26.7 per cent and 30.4 per cent, respectively.
“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 a more severe Covid-19. The multi-systemic inflammatory response to the virus may also be responsible for persistent Covid-19 symptoms in survivors,” Dr Moy said, adding that UM’s findings in these two aspects were comparable globally.
Dr Moy opined that long Covid in the more severe form “will definitely put pressure” on the health care system. “These patients may not be able to return to work and lose their source of income.”
For those who suffer from fatigue, cognitive impairment or brain fog, they may have their work productivity reduced. “From our study, long Covid patients reported reduced work productivity and increased absenteeism,” Dr Moy noted.
Khairy said last Tuesday that the majority of long Covid patients at 60 per cent to 70 per cent took six months to be able to return to work after infection, while the remaining 30 per cent to 40 per cent needed three months.