For people with asthma, having the flu can increase the risk of asthma attacks. People with asthma who have the flu are also at greater risk of developing pneumonia. It is therefore important for people with asthma to receive the flu vaccine.

Influenza, or the flu, is a viral disease that affects the respiratory tract.

Asthma is a chronic disease that causes inflammation and contraction of the airways. Although these conditions are different, both affect the respiratory tract and may interact in a way that affects people with asthma.

People with asthma who get the flu are more vulnerable to developing pneumonia, a complication of the flu. Therefore, it is advisable for people with asthma to receive a flu vaccine, which effectively fights off infection and often makes flu symptoms less severe. Fortunately, the injectable flu vaccine is safe for both adults and children with asthma.

This article explores how the flu affects people with asthma. It also provides safe protocols for receiving the flu vaccine as a person with asthma and information about flu treatment and prevention for people with asthma.

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To understand how the flu can affect people with asthma, it is worth being clear on what these conditions are and what they mean for those who have them.

A 2021 review explains that asthma is a chronic condition that can be more or less severe from person to person. Doctors and scientists understand that asthma affects a person’s respiratory system by causing inflammation in their airways. This inflammation can cause the airways to become narrower, making it harder for a person to breathe. For this reason, asthma can be a life threatening condition when it suddenly worsens.

The name for an acute exacerbation of asthma is an asthma attack. Symptoms include:

Both asthma itself and asthma attacks have various triggers, which may again differ from person to person. The following are common asthma triggers:

The review mentioned above also notes that viral respiratory tract infections can trigger asthma. As another 2021 review explains, the flu is one such infection. Symptoms of the flu include:

A variety of influenza viruses can cause the flu, which often comes in seasonal epidemics. In temperate parts of the world, these epidemics usually arise during autumn and winter. The flu can be fatal for certain groups of people, including:

For this reason, doctors often recommend that at risk groups receive seasonal flu vaccines. These can lower the risk of infection and make symptoms less severe.

As the Centres for Disease Control and Prevention (CDC) explains, the flu can complicate a person’s asthma in several ways.

As already noted, the flu can trigger asthma attacks. But because a flu infection can cause further inflammation of the airways, such infections can also worsen asthma symptoms in general. Having asthma can also make a person more likely to develop complications from the flu, including pneumonia.

Among children who need hospital treatment for the flu, asthma is the most common condition. Asthma is also very common in adults who require hospital treatment due to the flu.

Generally speaking, the flu vaccine is a potent defense against influenza infections. The CDC notes that the Food and Drug Administration (FDA) has approved injectable flu vaccines in the United States for people over 6 months old. This includes those who have asthma.

The injectable flu vaccine is not the only form of flu vaccination, however. There is also a nasal spray vaccine. The CDC states that children under 4 years old with asthma should not receive this vaccine. In people with asthma who are 5 or older, the CDC advises caution.

There is good scientific evidence that flu vaccines can help people with asthma. A 2017 meta-analysis found that people with asthma are less likely to get the flu after receiving a flu vaccine. The vaccine also seems to reduce the chances that people with asthma will experience an attack or flare-up.

A 2020 study found similar results, stating that flu vaccines have great potential for reducing asthma attacks related to flu.

As well as taking the flu vaccine, people with asthma can take preventive measures to reduce their chances of infection with the influenza virus. The CDC lists some such measures, which equally apply to those who do not have asthma, such as:

  • avoiding close contact with anyone who is ill
  • regularly washing the hands with soap or an alcohol-based hand wash
  • avoiding touching the mouth, nose, or eyes

If an individual with asthma does contract the flu, the CDC recommends that they receive the standard line of treatment. These are antiviral drugs that function to stop the flu virus from making more copies within a person’s body. This makes it easier for a person’s immune system to fight the virus, improving symptoms and recovery time. People should take antivirals within 48 hours of the onset of flu symptoms for maximal benefit.

However, not every antiviral flu drug is safe for people with asthma. In particular, people with asthma should not take the drug zanamivir (Relenza). This is because zanamivir may cause wheezing in individuals with asthma.

People with asthma can take the drugs oseltamivir (Tamiflu) and peramivir (Rapivab).

Flu can worsen asthma symptoms and increase the likelihood of a person having asthma attacks.

Many typical prevention and treatment options for the flu are available to those with asthma. Most flu vaccines are perfectly safe for people with the condition. Doctors recommend that people with asthma receive flu vaccines to prevent complications from both asthma and the flu should a person with asthma contract the illness.

A person should speak with a doctor or pharmacist about receiving a flu vaccine if they have asthma.