Pulmonary complications of COVID-19

With over a year since the pandemic was announced and multiple variants of COVID-19 spreading and infecting people, the basics of the virus are the only things to be sure of.
With multiple studies being carried out over the long-term effects of COVID-19, and the effect of the vaccines, it has become clear that the respiratory system is taking the hardest hit from the virus.
The virus targets the lungs and is mainly spread through respiratory droplets which form by coughing, sneezing, talking loudly or even singing.

How does COVID-19 affect the lungs

The virus first attacks the lungs. The virus invades cells in the respiratory system and is thought to attack the epithelial cells lining the airways. Epithelial cells provide barrier protection, repair function, fluid balance, clear out particulates like viruses and pollen.
Coughing and shortness of breath are the most common symptoms of COVID-19. Multiple studies have shown that COVID-19 leads “to a wide spectrum of respiratory diseases with an extremely high incidence of acute respiratory distress syndrome.”

What are the most common lung issues which stem from COVID-19

COVID-19 can lead to many lung complications including

Pneumonia caused by COVID-19

Normally pneumonia affects a single lung and double pneumonia affects both lungs. In pneumonia caused by COVID-19, usually, both lungs are affected. In pneumonia, the lungs fill with fluid which hampers the air sacs’ ability to absorb oxygen. Symptoms normally include shortness of breath and cough.
Pneumonia caused by COVID-19 can be severe, but people have been known to recover.


Sepsis is a blood infection where the body has a severe response to an infection and starts attacking itself. Symptoms of sepsis include a high fever, a rapid heart rate, breathing difficulty, and confusion.
It can lead to multiple organ failures and even when a patient survives sepsis, they can be left with lasting damage to the lungs and other organs.

Pulmonary fibrosis

There have been some instances of COVID-19 patients developing pulmonary fibrosis. Currently, there is no clinical data on the frequency of post-COVID-19 pulmonary fibrosis, estimates are that around 1/3rd of COVID-19 patients are affected by this. Lung damage caused by pulmonary fibrosis cannot be repaired. Currently, there is medication available to ease symptoms. The medication route for post-COVID-19 pulmonary fibrosis remains unclear. Usually, some individuals with pulmonary fibrosis undergo a lung transplant.

Acute Respiratory Distress Syndrome (ARDS)

Acute Respiratory Distress Syndrome is a form of lung failure where the patient requires assistance to breathe since they are not able to do it on their own. Patients are usually put on ventilator support. While studies on post-COVID-19 Acute Respiratory Distress Syndrome are still going on, some reports have attempted to try to understand the heterogeneity of COVID-19-associated ARDS and suggest the best ventilatory strategy for patients. Largely the conclusion remains that every individual will have to be treated based on their characteristics, preferences and values.

This leads us to another point. There are three main factors that affect lung damage risk in COVID-19 infected patients. They are:

Severity of infection

The severity of infection is the biggest deciding factor in lung damage. In case of a mild infection, there are fewer chances of the lung tissue being damaged. In case of a severe infection, there are higher chances of the lungs being more damaged.

Existing health problems

Individuals with existing lung or heart problems are at greater risk of developing lung complications. Especially patients who already suffer from chronic obstructive pulmonary disease. Another factor to be considered is the age of the patient. Older individuals have less elastic lung tissues, which reduces the capacity of the lungs to deflate during exhalation.

Timely treatment

Timely treatment is another key factor in a patient’s recovery and long-term effects of COVID-19. Treatment and care on time can greatly help reduce the chances of permanent lung damage.

What next

It has been universally acknowledged that healthcare workers are still in the containment mode of the pandemic. This means that when infection rates drop and fewer people need to be admitted because of COVID-19 infection, that’s when the attention will turn to those suffering from the consequences of their infection. Currently, there are studies on what has been termed as ‘long COVID-19 survivors’, people who technically recovered from the virus but continue reporting symptoms of fatigue, shortness of breath and aches and pains.

Lung damage especially takes time to reverse, and the healing phase itself introduces new symptoms in patients. According to standard evidence on lung damage, it can take anywhere from three months to a whole year before damaged lung tissues start healing and the lung capacity comes back to normal.
This is also dependent on external factors such as the environment, quality of air the patient is recovering in, etc.

Till then the classic advice of focusing on nutrition, trying to stay as healthy as possible and safe from the virus as possible applies.