Where do they get the idea that vaccines shed?
Does the FluMist Vaccine Shed?
Remember, shedding occurs when an infectious agent, typically a virus, can be found in urine, stool, or other bodily secretions. Shedding is not specific to vaccines though. Shedding occurs very commonly after natural infections too, which is one reason they are so hard to control.
So does the Flumist vaccine shed?
Yes, it does, and it isn’t a secret.
There is actually a warning about shedding and Flumist – to avoid contact with severely immunosuppressed persons (e.g., hematopoietic stem cell transplant recipients in a protected enviornment) for seven days after vaccination because of the theoretical risk that their severe immunosuppression might allow the weakened flu strain to somehow cause disease.
This warning obviously doesn’t apply to the great majority of people though.
And it shouldn’t be surprising that it sheds, after all, it is a live virus vaccine that is squirted in your nose!
Why isn’t it usually a problem?
Flumist contains attenuated viral strains of the flu that are temperature-sensitive, so even if you did get infected with the weakened flu strains from Flumist via shedding, they wouldn’t cause disease.
Another way to think about it is that the folks who actually get the Flumist vaccine don’t get the flu, so why would you get the flu if you were simply exposed to the vaccine virus by shedding?
The real concern with shedding is when it leads to folks actually getting sick.
Trying to scare folks about Flumist shedding is just like when they talk about the MMR vaccine, pushing the idea that the rubella vaccine virus might shed into breast milk or measles vaccine virus into urine. Either might happen, but since it won’t cause infection and disease, it certainly isn’t a reason to skip or delay your child’s vaccines.
What to Know About Shedding and Flumist
The Flumist vaccine does indeed shed, but unless you are going to have contact with someone who is severely immunocompromised in a protected environment, this type of shedding isn’t going to get anyone sick and isn’t a reason to avoid this vaccine.
More on Shedding and Flumist
- CDC – Live Attenuated Influenza Vaccine [LAIV] (The Nasal Spray Flu Vaccine)
- FDA – FluMist
- “Vaccine Shedding”: Time Up For Another Vaccine Myth
- Vaccine Shedding : Should You Really Be Concerned?
- Live Vaccines and Vaccine Shedding
- The Chickenpox Vaccine and Shedding Concerns
- Ask the Experts about Rotavirus Vaccines
- Rotavirus vaccine shedding poses little risk
- Guest post: “Viral Shedding” is not something to worry about
- 18 assertions about vaccines: #17 All live virus vaccines shed and cause diseases
- Can vaccines cause or spread diseases?
- Recommendations for live viral and bacterial vaccines in immunodeficient patients and their close contacts
- 2013 IDSA Clinical Practice Guideline for Vaccination of the Immunocompromised Host
- Fearless Defenders of the Immunocompromised Patient
- Vaccinations and Immunocompromised Children
- CDC – Altered Immunocompetence Guidelines for Immunizations (ACIP)
- AAP – Immunization in Immunocompromised Children (Red Book)
- Vaccination recommendations for the adult immunosuppressed patient: A systematic review and comprehensive field synopsis.
- Clinical Trial – Evaluate the Shedding and Immunogencity of Different Formulations of FluMist in Children 24 to <48 Months of Age (FluMist)
- Study – Shedding and immunogenicity of live attenuated influenza vaccine virus in subjects 5-49 years of age.
- Study – Duration Of Virus Shedding After Trivalent Intranasal Live Attenuated Influenza Vaccination In Adults
- Study – Detection of measles virus RNA in urine specimens from vaccine recipients.