Nearly 100 Million People Across World Are Estimated To Have Had Long Covid: Study

For those who had to be hospitalised for Covid-19, pooled prevalence estimate for long Covid was 0.57, which means 57% of the people who required hospitalisation for Covid-19 suffered from long Covid.

representational image of people registering for Covid-19 test at a hospital in Ghaziabad | Photo: Getty

New Delhi: New or persisting health problems in a recovered coronavirus patient, at four or more weeks after infection, and even after testing negative, is a big modern medical challenge. The condition has been described as Long Covid, and more than 40 per cent of Covid-19 survivors worldwide are estimated to have experienced this, according to researchers from the University of Michigan.

Earlier, 40 studies across 17 countries were conducted on patients who were suffering from Long Covid, and based on the review of these studies, the researchers from the University of Michigan made some estimates. The study, posted on medRxiv (a preprint server for Health Sciences) last week, is yet to be peer-reviewed.

This persistent state of illness can also be termed as 'post Covid condition', 'chronic Covid syndrome', 'late sequelae of Covid-19', 'long haul Covid', 'post-aculate Covid-19, among other names. 

The post-Covid "long haulers" include fatigue, shortness of breath, body aches, inability to exercise, difficulty concentrating and sleeping, and headache, different studies have noted. 

Since the patients suffer a range of chronic illnesses after a bout of Covid, the National Institutes of Health (NIH) has coined a unifying name — post-acute sequelae of SARS-CoV-2 infection or PASC. Recovery within a few weeks or months is observed in people who contract Covid-19, but complications such as chronic lung, heart, kidney and/or brain damage may occur in some patients. 

Long Covid Rate 49% In Asia

As many as 40 studies were reviewed by the researchers, of which nine were from North America, one was from South America, 17 were from Europe, 11 from Asia, and two from other regions. All the studies considered PASC as ailments persisting at least 28 days after diagnosis of or recovery from coronavirus, and included prevalence, risk factors, duration, and associated symptoms. The researchers conducted a meta-analysis by considering variation in PASC prevalence, in accordance to hospitalisation status.

According to the report published on medRxiv, the pooled PASC prevalence worldwide was estimated to be 0.43 or 43 per cent. For the people who had to be hospitalised for Covid-19, the pooled prevalence estimate for long Covid was 0.57. This means that 57 per cent of the people who required hospitalisation for Covid-19 suffered from long Covid. 

Pooled data is obtained when data sets coming from different sources are combined. 

The researchers said 49 per cent of female survivors, and 37 per cent of male survivors suffered from Long Covid. 

They estimated that Long Covid rate was 49 per cent, 44 per cent, and 30 per cent in Asia, Europe, and North America, respectively.

At 30, 60, 90, and 120 days after the index date, the global prevalence was estimated to be 0.36, 0.24, 0.29, and 0.51, respectively.

Twenty three per cent of the people who suffered from Long Covid experienced fatigue, while 13 per cent were affected by shortness of breath, joint pain, and memory problems.

The researchers noted that the study likely did not capture all cases of Long Covid. 

Prolonged Health Effects 'Can Exert Marked Stress On Healthcare System'

Since the SARS-CoV-2 virus has long lasting effects on human health, it is very important to understand Long Covid. The primary objective of the study was to examine the prevalence of PASC across the world, determine the anticipated healthcare needs, and assess geographic heterogeneities through a systematic review and meta-analysis, mentions the medRxiv report. 

The secondary aim was to estimate the prevalence of individual symptoms that have been commonly reported as PASC, based on existing literature. 

The findings suggest that more than half of the patients hospitalised due to Covid-19 suffer from long Covid, according to data available as of August 12, 2021.

Lowest PASC prevalence was found in North America (0.30), while the highest was observed in Asia (0.49), indicating geographic differences.

"The health effects of Covid-19 appear to be prolonged and can exert marked stress on the healthcare system, with 237 million reported Covid-19 cases worldwide as of October 12, 2021," the report quoted the researchers as saying.