People living with atopic dermatitis (AD)—the most common, difficult-to-treat form of eczema— often wonder if influenza vaccinations, or flu shots, are safe.
AD patients have an abnormal immune system that leads to a hyper-sensitive inflammatory response. In order to lower this inflammatory response, doctors prescribe systemic medications that can weaken the immune system. A weakened immune system makes it more difficult for the body to fight off viruses and infections.
This can feel like a Catch-22 for people with AD. They know vaccines are key to increasing the body’s resistance to bacteria and viruses, yet they also know they are prone to bacterial skin infections like Staphylococcus aureus (staph) that can wreak havoc on the immune system and become life-threatening if left uncontrolled.
People with eczema might wonder, “Doesn’t my immune system need to be strong to withstand a flu shot?”
For atopic dermatitis patients, it depends on the vaccine
Yes, flu shots are safe for people with weakened immune systems as long as they get a “killed” vaccine. A live vaccine contains living bacteria or viruses that have been modified to lose their disease-causing ability. A killed vaccine contains bacteria or viruses that are not living and therefore do not pose any threat to a weakened immune system.
Even though live vaccines have lost their disease-causing ability, medical professionals do not recommend administering one to a person with a deficient immune system. Also, family members or household contacts should not receive live vaccines as they might transmit the live virus to an immune-deficient member of the household.
The Centers for Disease Control (CDC) recommends the use of a “killed” injectable influenza vaccine during the 2017-2018 flu season. The nasal spray flu vaccine is a live attenuated influenza vaccine and is not recommended by the CDC.
How flu shot is administered also matters for eczema
Now, here’s where things get interesting for people with AD. There are two types of injectable flu shots: intradermal (injected into the skin) vs. intramuscular (injected into the muscle).
Intradermal flu shots have been widely used since 2011. They use a much smaller needle and require 40 percent less antigen, which is the part of the vaccine that helps your body build up protection against flu viruses. This is useful because the same amount of available antigen can make more doses of the vaccine and save more lives.
However, it is not known whether people with AD respond differently to intradermal and intramuscular flu shots, especially since a large number of people with AD have skin colonized with staph bacteria. A group of researchers set out to solve this mystery, and the results of their study were published in the February 2017 issue of The Journal of Allergy & Clinical Immunology.
Intradermal flu shots were administered to patients with moderate to severe AD as well as those who do not have the disease. They found no difference in vaccine response to intradermal flu shots between patients with AD and those without. Vaccines injected into the skin are just as effective on people with AD as those who do not have the disease.
Intramuscular flu shots were administered to people with AD, and scientists then compared the antibody response in AD patients receiving the intradermal vs. intramuscular vaccine. Once again, they found no difference in vaccine response between with people AD whose flu shots were injected into their skin vs. their muscle.
However, a subset of patients with AD who had skin colonization by Staphylococcus aureus developed a lower response to two of the three influenza strains in the vaccine. This was only when the vaccine was administered intradermally.
Given that a majority of people with AD have staph bacteria colonized in their skin, moving forward, it may be recommended that people with AD receive intramuscular flu shots instead of intradermal.
For more information on eczema and flu shots, check out this video courtesy of the American Academy of Dermatology.