People who have recovered from COVID-19 infection are said to be left with 20 to 30% reduced lung function, leaving them struggling for breath when trying to walk.

Such reports are based on very limited research evidence at the moment. They follow observations from 12 patients who were hospitalised with COVID-19 in the first stages of the outbreak in Hong Kong. After recovery “two to three” of the 12 were said to have reduced lung function, while others were said to have lung scans showing changes suggestive of damage.

This is a small number on which to conclude. The latest information from the World Health Organisation shows that over 2.5 million COVID-19 infections have been confirmed worldwide. Many thousands more may have been infected but remain untested, or have recovered without accessing medical attention.

Large scale, ongoing follow-up will be needed to better understand whether COVID-19 is associated with persistent respiratory effects, and how this varies by infection severity or underlying patient characteristics.

Where did the story come from?

The medical director of the Hong Kong Hospital Authority’s Infection Disease Centre reported the observations for 12 patients at a press conference in early March 2020. The current summary is based on a briefing by Business Insider, Australia. The findings were said to be first publicized in the South China Morning Post.

What is the basis for the claim?

This report is brief. The 12 patients were said to be among the first to have recovered and been discharged from hospital earlier this year in Hong Kong.

The medical director of the Hong Kong Hospital Authority reported that “two to three” of 12 saw changes in their lung capacity. He was quoted “they gasp if they walk a bit more quickly” and that “some patients might have around a drop of 20 to 30% lung function after full recovery.” The briefing continues that it was suggested that patients could do cardiovascular exercises to improve their lung capacity over time.

The director further reported that CT scans of nine patients’ lungs (presumed to be nine of the 12) showed “ground glass” patterns. This refers to white patches (opacities) seen on radiological film, which could mean various things like fluid build-up, inflammation or scarring in the lungs. They are recognised as typical CT findings in COVID-19 infection and are part of the “confirmed case” definitions.

Caution needs to be taken when drawing firm conclusions at this stage. These are short-term observations of a very small, localised sample of patients. We know little further about these patients, such as their prior respiratory health or comorbidity, and whether these may be temporary or long-term changes.

The medical director highlighted that it is too early to establish the long-term effects of COVID-19.

What do trusted sources say?

The WHO reports that around 80% of people infected will experience mild symptoms and recover without treatment, while it is thought that some may remain completely asymptomatic. However, 1 in 6 people may develop breathing complications. People with existing health problems like respiratory or cardiovascular disease are expected to be at higher risk.

The WHO and UK government sources emphasise infection control measures and social distancing for all.  Vulnerable groups, including those with chronic lung conditions like cystic fibrosis, asthma or COPD, are advised to self-isolate at home until at least the end of June.  People experiencing breathing difficulties, cough or fever are advised to seek medical attention.



1.     Business Insider. Some people who recover from the coronavirus might be left with ’20 to 30%’ less lung function, and gasping for breath when they walk quickly, Hong Kong doctors said

2.     Science Alert. Those Who Recover From Coronavirus Can Be Left With Reduced Lung Function, Say Doctors

Reading list

  1. British Lung Foundation. Coronovirus and COVID-19
  2. Public Health England. Guidance on shielding and protecting people who are clinically extremely vulnerable from COVID-19
  3. World Health Organisation. Advice for the public.