Some people with asthma have reported that their asthma symptoms worsened after they received the COVID-19 vaccine. However, there is no evidence that the vaccine worsens asthma symptoms or that asthma makes the COVID-19 vaccine more dangerous.

People with moderate-to-severe asthma do have a higher risk of hospitalization if they develop COVID-19. Research shows that the COVID-19 mortality rate is also higher among these individuals. Due to this, any purported or hypothetical risks associated with asthma and the COVID-19 vaccine are less significant than the very real risks of getting COVID-19.

People with asthma often also have underlying allergies. These allergies can trigger asthma symptoms, making them worse. There is no evidence so far that asthma increases the risk of an allergic reaction to the COVID-19 vaccine, though. Rates of allergic reactions to the vaccine — including the Pfizer-BioNTech and Moderna vaccines — are much lower than rates of allergic reactions to other substances.

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Keep reading to learn more about asthma and the COVID-19 vaccine, including how it may affect symptoms and when to contact a doctor.

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No current research supports the notion that the COVID-19 vaccine makes asthma symptoms worse. People with asthma have participated in vaccine trials, so if there were serious negative outcomes, the data would show it.

However, people with asthma, as with other vaccine recipients, may experience temporary expected side effects 1–2 days after getting the vaccine.

The Centers for Disease Control and Prevention (CDC) regularly publish data on adverse vaccine reactions. In early vaccine trials, mild vaccine reactions were common, but severe reactions were almost nonexistent.

Although the findings do not focus specifically on people with asthma, there is currently no evidence that people with this condition are more likely to have vaccine reactions. However, some people with asthma find that fever or illness can be an asthma trigger. It is possible, therefore, that those who have a reaction to vaccines may experience a temporary worsening of asthma symptoms as they would due to fever or other flu-like illnesses.

With the Pfizer vaccine, 77.4% of recipients experienced at least one systemic reaction, such as a fever, headache, or muscle pain following the second dose. These reactions were more common in people under the age of 55 years.

With the Moderna vaccine, 81.9% of people aged 18–64 years experienced at least one systemic reaction after their second dose. Rates were lower among older adults, at 71.9% following the second dose.

The Janssen, or Johnson & Johnson, vaccine had a lower overall rate of side effects. Among recipients aged 18–59 years, 61.5% reported a systemic reaction compared with 45.3% of people aged 60 and over.

In all groups, placebo reactions were also common. For example, 38.4% of Moderna placebo recipients aged 18–64 reported experiencing a systemic reaction. Janssen vaccine recipients aged 18–59 reported placebo reactions at a rate of 33.1%.

People with asthma are more likely to have allergies. However, rates of allergic reactions to COVID-19 vaccines are extremely low, and there is no evidence that people with asthma are more vulnerable.

Anaphylaxis risk

Early data on 1,893,360 recipients of the Pfizer vaccine found an overall rate of anaphylaxis — the most severe type of allergic reaction — of 11.1 per 1 million doses. These reactions were all to the first vaccine and happened within 15 minutes of getting it. There were no deaths.

The rate of Moderna-related anaphylaxis among 4,041,396 vaccine recipients was 2.5 per 1 million doses, and again, there were no deaths.

Among more than 8 million Janssen vaccine doses, CDC investigators found 79 reports of anaphylaxis but were able to tie just four to the vaccine. This made the rate of anaphylaxis less than 0.5 cases per 1 million doses.

The American Academy of Asthma and Clinical Immunology advises anyone with an allergy to any of the vaccine’s ingredients to avoid getting the shot. Otherwise, there is no evidence of an enhanced risk of serious allergic reactions.

Data suggest that asthma could be a risk factor for worse COVID-19 outcomes, especially if a person has moderate-to-severe asthma.

In a study of 7,590 people with COVID-19, 218 of whom had asthma, researchers found that:

  • People with asthma had higher COVID-19-related medical costs.
  • The risk of dying of COVID-19 was much higher among those with asthma. People with asthma had a 7.8% death rate compared with 2.8% among people without asthma.
  • Neither asthma severity nor the use of asthma medication affected COVID-19 outcomes.

However, researchers also found that after adjusting for other factors, asthma was not an independent risk factor for negative COVID-19 outcomes. This suggests that other factors associated with asthma might play a role rather than asthma itself.

Viruses can trigger asthma symptoms, according to a Canadian Medical Association Journal article. This suggests that people with asthma may experience worsening asthma symptoms during a coronavirus infection. The authors of the article make the following suggestions for doctors treating people with asthma:

  • Patients should remain on their asthma medication during the pandemic.
  • Doctors should avoid nebulizers, as they can generate aerosols, increasing the risk of viral transmission. Oral steroids can be helpful instead.
  • People with asthma should practice strategies to reduce the spread of SARS-CoV-2 — the virus that causes COVID-19 — but do not need to stop taking medication that suppresses the immune system.

Learn more about asthma and COVID-19 here.

It is not possible to get the SARS-CoV-2 virus from the vaccine, so a person will not develop COVID-19. There is also no evidence of widespread serious reactions. Anecdotal reports of serious reproductive harm, stillbirths, pregnancy loss, and other issues are not grounded in science.

Nevertheless, as with all drugs, the COVID-19 vaccine can cause some side effects. The most common include:

  • pain, swelling, discoloration, or bruising at the injection site
  • tiredness
  • muscle pain
  • headaches
  • chills
  • fever
  • nausea or vomiting

Very rarely, a person might experience a more serious side effect. The CDC has reported a small number of cases of a rare type of blood clot following the Janssen vaccine.

A 2020 systematic review and meta-analysis of 42 studies involving 8,271 people with COVID-19 found that 21% developed blood clots. This makes the risk of a blood clot from COVID-19 more than 100,000 times higher than the risk of a blood clot from the Janssen vaccine.

Good management of asthma symptoms may help reduce the risk of serious asthma complications, both during the pandemic and beyond. People can reduce their risk by:

  • using asthma medications as a doctor recommends and asking about a rescue inhaler
  • identifying asthma triggers, such as pollution, stress, and allergens, and then finding ways to avoid them, such as wearing a mask outside
  • developing an asthma management plan with the help of a doctor and asking for additional guidance if asthma symptoms do not improve
  • reducing the risk of getting respiratory viruses by practicing frequent hand washing and getting vaccinated against the flu and COVID-19

Learn more about remedies for asthma here.

People with asthma should talk with a doctor about their risk of severe COVID-19, strategies they can adopt to mitigate this risk, and any concerns that they have about medications that suppress the immune system.

It is important to call a doctor if:

  • a person develops signs of COVID-19 or has a positive SARS-CoV-2 test
  • asthma symptoms get worse
  • the side effects of a COVID-19 vaccine do not go away within a day or two

A person should seek emergency medical care if:

  • they have trouble breathing, and a rescue inhaler does not work
  • they feel confused or unable to breathe following a COVID-19 vaccine
  • a child with asthma in their care has trouble breathing

Learn more about asthma attacks here.

There is no evidence that people with asthma should avoid getting the COVID-19 vaccine or worry about serious side effects.

There is, however, ample evidence that COVID-19 is more dangerous for people with asthma — especially if they have other preexisting conditions — than for other people.

Getting a COVID-19 vaccine is one of the best things a person can do to avoid serious breathing problems. People with a history of allergies or severe allergic reactions should discuss the risks and benefits of vaccination with a doctor.

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