Studies have shown that people with asthma are likely to have worse symptoms when they are exposed to the influenza virus because of immune system differences.
Asthma and flu (influenza) are two conditions of the respiratory tract that significantly affect millions of people worldwide. Flu is caused due to an influenza virus and is a highly transmissible illness while asthma is a chronic non-transmissible inflammatory disease of the airways mainly caused due to allergic (dust, dander and pollens) and non-allergic (tobacco smoke and viral infections) factors.
Studies have shown that people with asthma are likely to have worse symptoms when they are exposed to the influenza virus because of immune system differences. People with asthma tend to have a weaker immune system while healthy people show strong immune triggering reactions.
The respiratory system in our body, compared to other body organs, is more exposed to the external environment due to its large surface area. As the functionality of the lungs includes in and out of the air, they are bound to be exposed to infectious agents.
Though the structural barriers and immune defences protect the lungs from infections and damage of any kind, prolonged exposure to these harmful respiratory agents can proceed to the development of asthma in susceptible individuals. According to the CDC, one out of every eleven children and one out of every twelve adults suffer from asthma.
Common respiratory viruses such as influenza virus constantly circulate in the environment and can infect people of all ages, especially children. Therefore, simply based on the increased cases of asthma, the risk of exposure to influenza virus in asthmatic is high.
However, not all types of asthmatics are an easy target for influenza virus. This makes the immunological background important to identify why asthmatics are more prone to influenza compared to healthy adults.
The whole mechanism underlying the increased risk of influenza in asthmatics are poorly understood, but some studies do talk about the deficiency of antiviral immunity in people with asthma.
One of the reasons is the increased use of inhaled corticosteroid (inhaler) or oral corticosteroid. People with asthma are often suggested to keep inhalers, which are a type of drugs that lower inflammation of the lungs (the main cause of asthma). These corticosteroids prevent against severe asthma complications due to influenza infection but are also known to suppress the immunity in the long run.
Another reason is the suppression of T-lymphocyte or those cells which are responsible for killing the infection by activating immune cells to produce cytokines. A study was carried out based on lung samples from asthmatics and healthy volunteers. It was found that the samples from healthy people showed a strong immune system-triggering reaction to the flu virus, compared to much weaker reactions in asthma patients.
Annual immunization with influenza vaccine is recommended by the major health governing bodies such as the WHO and the CDC. A study has shown that influenza vaccination can prevent around 59%-78% of asthma attacks leading to fewer hospitalisations or emergency visits. Also, aggravation of asthma, other respiratory illness and usage of medications were reduced.
The study requires more research as there were limitations on the study such as patients should have laboratory-confirmed influenza.
Keeping asthma action plan ready beforehand will help you avoid the condition effectively. However, if you are asthmatic and get flu, connect to a medical expert soon and don't wait for the condition to get worse.
The lungs of asthmatics are already compromised. As flu is a viral infection that affects the lungs, therefore, it can aggravate the symptoms in patients with asthma and make them fall ill too quickly.
Asthma is highly prevalent in people with a weakened immune system. This is because asthma is a chronic inflammatory disease which means, the inflammatory response in those people is weak, which is the body's natural defence mechanism against pathogens.