Not every coronavirus patient who goes on to test negative for the infection returns to a clean bill of health, with some enduring brain fog, palpitations and even organ damage.
Statistics have repeatedly flagged elderly non-white men are more likely to become seriously ill and die with the coronavirus itself.
It is therefore perhaps surprising that scientists from the University of Leicester have found white middle-aged women are most at risk of long COVID five months after being discharged from hospital.
Read more: Long COVID patient 'has good and bad days'
Watch: What is long COVID?
The results have not yet been published in a peer-reviewed journal, but appear on the pre-print site medRxiv.
"While the profile of patients being admitted to hospital with COVID-19 [the disease caused by the coronavirus] is disproportionately male and from an ethnic minority background, our study finds those who have the most severe prolonged symptoms tend to be white women aged approximately 40 to 60 who have at least two long term health conditions, such as asthma or diabetes," said lead author Professor Chris Brightling.
Co-author Professor Louise Wain added: "We know autoimmunity, where the body has an immune response to its own healthy cells and organs, is more common in middle-aged women.
"This may explain why post-COVID syndrome seems to be more prevalent in this group, but further investigation is needed to fully understand the processes."
The scientists have called long COVID's higher prevalence among white women specifically "intriguing".
The scientists analysed more than 1,000 people – average age 58 – who were discharged from hospitals across the UK between March and November 2020 after being admitted with coronavirus complications.
As well as uncovering how long COVID affects different sexes and ethnicities, the team found the majority (71%) of the participants did not feel fully recovered at five months post-discharge.
One in five (20%) had even "reached the threshold for a new disability".
Read more: Scientists get grasp on long COVID's cause
"Our results show a large burden of symptoms, mental and physical health problems, and evidence of organ damage five months after discharge with COVID-19," said co-author Dr Rachael Evans.
"It is also clear those who required mechanical ventilation and were admitted to intensive care take longer to recover, however, much of the wide variety of persistent problems was not explained by the severity of the acute illness.
"The latter [was] largely driven by acute lung injury – indicating other, possibly more systemic, underlying mechanisms."
Watch: Do coronavirus vaccines affect fertility?
Overall, each study participant had on average nine persistent symptoms.
The 10 most common complications were muscle pain, fatigue, physically slowing down, impaired sleep, joint discomfort or swelling, limb weakness, breathlessness, general pain, short-term memory loss and slowed thinking.
When it came to the participants' mental health, more than a quarter had symptoms of depression and anxiety, while over one in 10 (12%) showed signs of post-traumatic stress disorder.
Of the over two thirds (67%) who were working before they caught the coronavirus, 17% were not able to at five months post-discharge, while 19% had "experienced a health-related change in their occupational status".
The participants' recovery was clustered into four groups, one of which referred to having "pronounced" cognitive impairment, like brain fog. These patients tended to be older, male, not obese and have fewer underlying health conditions.
The other clusters were made up of patients with "very severe physical and mental health impairment with poor cognition", "severe physical and mental health impairment with minimal effect on cognition", and those who "felt recovered, [with] physical and mental health impairment [being] mild"
Long COVID is somewhat of a mystery, however, many blame widespread inflammation triggered by the immune system over-reacting to the coronavirus.
"When we looked at the symptom severity of patients five months after they were discharged from hospital, we found in all but the mildest cases of persistent post-COVID symptoms, levels of a chemical called C-reactive protein [CRP], which is associated with inflammation, were elevated," said Professor Wain.
"From previous studies, it is known systemic inflammation is associated with poor recovery from illnesses across the disease spectrum."
The so-called PHOSP-COVID study is also measuring how the treatments administered in hospitals affect a patient's recovery.
The steroid dexamethasone is routinely given to critically-ill patients after a June 2020 study found it cut the risk of death by a third among those on ventilators.
The results of the PHOSP-COVID study support the inexpensive drug reducing COVID deaths in hospital, but suggest the steroid does not impact a patient's later recovery.
Watch: Can you catch coronavirus more than once?
The scientists hope their results will help towards "a proactive approach to clinical follow-up with a holistic assessment" of long COVID patients.
Existing treatment guidelines recommend patients pace themselves, set realistic goals and join support forums.
"We are in the foothills of our understanding of long term effects of COVID," said Professor Chris Whitty, England's chief medical officer.
"This research provides useful information on the debilitating effects of COVID some people are living with months after being hospitalised.
"It is important we work out what exactly the various elements of what is currently termed 'long COVID' are so we can target actions to prevent and treat people suffering with long term effects."
Research has suggested long COVID may be four syndromes: post-intensive care; post-viral fatigue; long-term COVID; and permanent organ damage.
"I know long COVID can have a lasting and debilitating impact on the lives of those affected and I'm determined to improve the care we can provide," said health secretary Matt Hancock.
"Studies like this help us to rapidly build our understanding of the impact of the condition and we are working to develop new research so we can support and treat people.
"We are learning more about long COVID all the time and have given £20m ($27.4m) research funding to support innovative projects, with clinics established across the country to help improve the treatment available."
More than 300,000 people have been discharged from hospital after overcoming the coronavirus in the UK alone. Long COVID's exact prevalence is unclear, but has been estimated at around 600,000 patients.
NHS medical director Stephen Powis added: "As we have throughout the pandemic, as new evidence and treatments emerge, the NHS will respond quickly and get the latest treatments to patients quickly, as we did with dexamethasone.
"[The drug] was used on the front line of patient care on the day it was approved and which has since saved one million lives around the world."