The COVID-19 pandemic has brought lung disease and lung damage to the forefront of public health discussions. Early on, the respiratory virus was found to cause lung damage, and evidence showed that people living with lung disease face an increased risk of developing severe coronavirus symptoms.
Now, two years and multiple variants later, long-term lung damage remains a concern for both COVID-19 patients who already had lung disease and those who did not.
How COVID-19 Affects the Lungs
The original SARS-CoV-2 virus that spread throughout the globe in 2019 tended to cause significant damage to the lungs, according to the National Heart, Lung, and Blood Institute.1 The virus attached to the ACE-2 receptor in order to enter cells along the airways. From there, it would replicate and infect other cells. The ensuing inflammatory response damaged the air sacs in the lungs, leading to shortness of breath and potentially causing acute respiratory distress syndrome (ARDS). In turn, COVID-19 patients began requiring ventilators in large numbers, which led to a shortage of these critical machines.
Not all later COVID-19 variants shared the same dramatic impact on the lungs. For instance, the Omicron variant doesn't appear to infect lung cells as strongly or deeply as earlier variants and focuses more on the upper airways, according to research published in Nature.2
Lung disease, which includes conditions such as chronic obstructive pulmonary disease (COPD), asthma, and cystic fibrosis, has received limited attention compared with COVID-19. Yet COPD was the third leading cause of death worldwide before the pandemic, according to the World Health Organization.3 People living with COPD or other lung diseases have been at higher risk of developing severe complications from COVID-19, including pneumonia, acute respiratory distress syndrome (ARDS), and acute respiratory failure. Dr. MeiLan Han, chief of pulmonary and critical care at the University of Michigan, argued in an op-ed for the Los Angeles Times that underfunding for lung disease has limited treatment options as well as hampered pandemic response efforts.4
A study from the Annals of the American Thoracic Society reports that pulmonary dysfunction was a leading cause of death in patients hospitalized with COVID-19 in the early days of the pandemic.5 Pulmonary function changes and lung damage can persist in people with long-term symptoms of COVID-19 infection, signaling a need for additional monitoring and therapeutic options.
Connecting Long COVID and Lung Damage
No single definition has emerged to describe what's commonly known as long COVID or post-acute sequelae of SARS-CoV-2 infection (PASC). The condition is associated with lingering symptoms from the infection that range from mild to debilitating and last more than 30 days. Some long-term COVID-19 studies focus specifically on respiratory symptoms; however, the patient population exhibits symptoms as diverse as gastrointestinal issues to fatigue to cough, and it includes people with infections that span multiple variants. This makes it more challenging to draw solid conclusions about lung disease, particularly when most research is still in the early stages.
Here's what we know so far:
- Many people previously infected with COVID-19 have lasting lung changes. Multiple studies, including research published in Radiology and Physical Medicine and Rehabilitation, have found that between 30 percent and 50 percent of people hospitalized with COVID-19 had abnormal CT scans at 6 to 12 months after infection, most commonly with ground-glass opacity or fibrotic changes.6, 7
- COVID-19 lung damage is more common with severe disease. People who were hospitalized, developed pneumonia, or had ARDS are more likely to have changes in pulmonary function after recovering from infection.
- Bronchiolitis and diffuse alveolar damage are the two most common types of lung damage from COVID-19 regardless of disease severity. Inflammation of the bronchioles or fibrosis in the alveoli can lead to scarring, according to a separate study published in Radiology.8
- People who recover from mild COVID-19 cases may still experience ongoing respiratory symptoms.9 Even people not hospitalized for COVID-19 symptoms may still experience shortness of breath, cough, and fatigue more than 30 days after infection.
Longer-term studies will continue to consider how long COVID-19-inflicted lung damage lasts and whether it may be reversed. Johns Hopkins Medicine reports that lung damage can take three months to over a year to fully heal, meaning that many patients have not yet fully recovered.10 Much of the current research has not separated cohorts of people with existing lung disease to determine the long-term effects of infection. Further research is needed to better understand PASC and the long-term implications for people living with lung disease.
Staying Prepared for Respiratory Viruses
Ventilators took center stage early in the pandemic as hospital staff expressed fears they did not have enough equipment to treat the influx of patients. These machines have saved the lives of people struggling to breathe on their own due to lung dysfunction, whether from COVID-19 or from chronic conditions such as COPD. Ensuring ventilators are in good working order and that critical ventilator parts and accessories are stocked helps healthcare organizations stay prepared to address current lung disease patients and future COVID surges alike.
References
1. https://www.nhlbi.nih.gov/coronavirus/lungs
2. https://doi.org/10.1038/d41586-022-00007-8
4. https://www.latimes.com/opinion/story/2022-01-10/lung-disease-treatment-covid
5. https://www.atsjournals.org/doi/10.1513/AnnalsATS.202011-1381RL
6. https://pubs.rsna.org/doi/full/10.1148/radiol.2021211396
7. https://onlinelibrary.wiley.com/doi/10.1002/pmrj.12744
8. https://www.medicalnewstoday.com/articles/long-covid-can-it-cause-persistent-lung-disease
