Navigating flu season with PI

What is the flu?

Influenza, commonly known as "the flu," is a respiratory disease that usually comes on suddenly, with symptoms that vary from person to person. These symptoms may include aching muscles, sore throat, a dry cough, a runny or stuffy nose, fatigue, headache, a burning sensation in the chest, eye pain, sensitivity to light, and fever and/or chills (note that people with PI may not spike a fever).

Although many people think of the flu as harmless, from 2010-2020, the U.S. Centers for Disease Control and Prevention (CDC) estimates that between 12,000-52,000 people died of flu-related complications each year.

Colds, COVID-19, and the flu have overlapping symptoms but are different respiratory illnesses with different treatments, so it’s important to be tested if you feel sick. Note that it is also possible to get both COVID-19 and the flu at the same time.

Does PI put you at high risk for flu complications?

Except for those with interferon pathway deficiencies, people with PI are not necessarily at higher risk of developing complications from the flu unless they meet other high-risk criteria, such as: 

• Being 5 years old or younger (especially younger than 2 years old). 
• Being 65 years old or older.
• Have asthma, diabetes, or chronic lung, heart, kidney, liver, metabolic, or blood conditions, including conditions that may be complications of PI.
• Have had a stroke.
• Have a secondary immunodeficiency caused by disease (e.g., HIV or blood cancer) or medication (e.g., immunosuppressive therapy).
• Are pregnant.

The flu's most common complication is bacterial pneumonia, with other complications including viral pneumonia, myocarditis (inflammation of the heart muscle), and worsening of lung diseases. See a healthcare provider right away if you have:

• Difficulty breathing, shortness of breath, or rapid, shallow breathing.
• Blue-ish lips or nail beds.
• Rapid pulse.
• Chest or abdomen pain or pressure.
• Seizures.
• Signs of dehydration (not passing urine).
• A persistent cough, especially if you’re coughing up colored phlegm or mucus (yellow/green).
• Severe muscle pain, weakness, or unsteadiness.

Reye's syndrome is another flu complication that primarily affects children and causes severe vomiting and confusion. To decrease the chance of developing Reye’s syndrome, infants, children, and teenagers should not be given aspirin for fever reduction or pain relief.

How do you avoid the flu?

Get your yearly flu shot

An annual influenza vaccine is the most effective way to avoid getting seriously ill with the flu. Each year, the Advisory Committee on Immunization Practices (ACIP) at the CDC updates its recommendations for seasonal influenza vaccination. Because the vaccine changes every year to match circulating influenza virus strains, everyone 6 months of age or older needs a flu vaccine every year. 

Why should everyone be immunized? First, some people with PI may develop at least some antibodies or a T cell response, which is important for any viral infection, to the vaccine. Immunoglobulin (Ig) replacement therapy products (IVIG or SCIG) typically do not have protective levels of antibodies against current flu strains because manufacturing takes six months or more from the initial plasma donation. Second, household members of people with PI should get vaccinated to create a "protective cocoon" around the person with PI and decrease their exposure to the influenza virus. 

For the 2023-2024 season, all flu vaccines are quadrivalent, which means they protect against four different influenza virus strains, two influenza A and two influenza B strains. 

There are multiple types of flu vaccines available and selecting the right type is important. The inactivated or recombinant flu vaccine types are best for people with PI and their household members. People with PI and their household members should not receive the live attenuated flu vaccine. 

Additional recommendations from ACIP include:

• People ages 65 or older should receive the high-dose inactivated, adjuvanted inactivated, or recombinant vaccine because these formulations provide greater protection in older individuals. 
• Children 8 years old or younger who have either never been vaccinated for the flu or have only received one previous flu vaccine dose should be vaccinated with two doses of flu vaccine spaced four weeks apart.
• Beginning with the 2023-2024 season, additional safety measures are no longer recommended for people who are allergic to eggs, regardless of the severity of previous allergic reactions. People with egg allergy may receive any vaccine (egg-based or non-egg-based) that is appropriate for their age and health status.

The flu vaccine is safe and does not cause the flu, and individuals on Ig replacement therapy do not need to coordinate vaccine timing with their treatment. The vaccine is available from late summer, and the CDC recommends getting vaccinated in September or October for the best protection.

Stop the spread

Remember that flu vaccines are a crucial tool during respiratory virus season, but you should take advantage of other tools, too:

• Regularly wash your hands with soap and water for 20 seconds, especially after coughing or sneezing. Hand sanitizer may not be as effective in killing the flu virus. 
• Keep a distance of at least six feet from individuals who are sick. 
• Use a well-fitted mask over your nose and mouth to avoid inhaling droplets that can spread respiratory viruses like influenza and COVID-19. During the 2020-2021 and 2021-2022 flu seasons, not many people got the flu because they were wearing masks for COVID-19 prevention, demonstrating that masks are effective against the transmission of both flu and COVID-19.
• Try not to touch your nose, mouth, or eyes, as germs can spread this way. 
• During flu season, those with PI should consider avoiding crowded indoor areas such as shopping malls.
• When coughing or sneezing, cover your nose and mouth with a sleeve, elbow, or tissue. Dispose of the tissue after use. 
• Stay home from work or school for 3-4 days after experiencing flu symptoms.