Can COVID-19 cause asthma?

Currently, the connection between SARS-CoV-2 and asthma remains largely unclear. However, existing knowledge about the connection between respiratory viruses and the progress of asthma, suggests that COVID-19 can be a trigger for significant outcomes.

Here to provide an expert insight into this complex topic is Dr Sandip Banerjee, esteemed respiratory and sleep physician with significant experience on COVID-19 treatment. He talks the effects of COVID-19 on the respiratory system, the chances of developing asthma after contracting the disease, and the difference between coughs.

Can you develop asthma after having COVID-19?

The most serious form of COVID-19 appears to be linked to a cytokine storm, a sudden increase in levels of cytokines into the blood, that results in hyper inflammation. This inflammation causes severe damage to the lungs, producing long-lasting effects in the respiratory system of patients that overcome the disease. The inflammation of airways, the remodelling of tissue, and bronchoconstriction (the contraction of smooth muscles in the bronchi) that characterise respiratory infections, could then precipitate the start of asthma symptoms.

In addition, respiratory infections like COVID-19, can also damage the structure of the epithelial barrier (a cell layer that prevents harmful microorganisms from contaminating immune tissue), during their infectious process. In this aspect, the replication of respiratory viruses in the bronchial linings of the lungs, can lead to a loss of ciliated cells, which are responsible for clearing microbes out of the airways. This can eventually cause morphological damages that develop into airway hyper responsiveness and worsening of asthma.

However, little has been discovered specifically about the effects of SARS-CoV-2 in the lung function of patients who have survived the disease.

Is there a difference between a COVID cough and an asthmatic cough? What should people do if they experience wheezing after COVID-19?

According to a new study, one in six middle aged people (17%) who contracted SARS-CoV-2 also experienced long COVID symptoms, in comparison to 1 in 13 (7.8%) younger adults. The preliminary findings of the CONVALESCENCE study also found that women were half more likely than men to experience long COVID, and that risk for long COVID symptoms is linked to a previous diagnosis of asthma in addition to poor pre-pandemic mental and physical health.

It is essential to understand here that long COVID is associated with a variety of symptoms, including fatigue, breathlessness, headaches and coughs, because it is part of a multi-systemic response. Most often, the cough is dry and related to underlying lung inflammation or scarring. It is also likely that the reliever inhaler you use for your asthma may be ineffective against similar symptoms, like breathlessness and coughing caused by COVID-19.

The cough caused by poor control or an aggravation of asthma is also mostly dry, although in some cases, it can come with phlegm (chest mucus) if in particular, it is associated with a post nasal drip (excess mucus dripping down the back of the throat). This type of cough is usually worse during the night, and can come with chest tightness or heaviness, and breathlessness. An increase of your asthma medications and a drop in your peak expiratory flow rate, should be enough to improve it.

Can COVID-19 vaccinations exacerbate asthma symptoms? How should people take care of this?

After receiving the vaccine for COVID-19, some people with asthma said their asthma symptoms worsened, but there is no scientific proof as of yet that can back this. Alongside other viral infections, SARS-CoV-2 may cause worsening of asthmatic symptoms, but no evidence exists to support the theory that patients with bronchial asthma have an increased risk of suffering worsening of asthma when receiving the COVID-19 vaccination.

The only worsening, analysed by a few published case studies, is in asthma control. Even then, the only published study – by Eggert et al. 2021 – found that there was no difference in the potential side effects between people with asthma and those that were non-asthmatics. As it is known, one study is insufficient to clear all the uncertainties surrounding the topic.

My advice would be to get double vaccinated and also have your booster vaccine, because vaccination lowers your risk of serious illness, hospitalisation and new COVID-19 variants, including those that could affect asthma more directly.

Has treatment for asthma changed after COVID-19?

In the UK, hospitals saw a decrease in the number of patients admitted with symptoms of worsening asthma. However, a higher predominance of asthma was identified among people hospitalized with COVID-19 in USA and Australia. This information suggests that there is a chance that the majority of people with asthma could be at an increased risk of contracting serious illness from COVID-19. This risk will be higher if they have a non-allergic type of asthma. Still, this probability is significantly lower than for other conditions, meaning that most people with asthma are not at a, what is considered, higher risk from coronavirus itself.

On the other hand, asthma not only has a harmful effect on the airways of patients, but also, cause a decrease, or clog, an adequate response to respiratory viruses, resulting in an aggravation of symptoms. This can enhance the use of asthma medications as well as, deteriorating the control of asthma symptoms. 

Dr Sandip Banerjee is a highly qualified respiratory and sleep physician based in Sevenoaks and Maidstone, who specialises in a variety of respiratory-related conditions, including asthma, sleep apnoea, pleural mesothelioma, and lung disease. If you would like an expert assessment for your asthma, or simply wish to know more about the effect of COVID-19, make sure to visit Dr Banerjee’s profile today.