How effective is the nasal-spray seasonal flu vaccine LAIV (FluMistÂ®)?
In one large study among children aged 15-85 months, the seasonal nasal-spray flu vaccine LAIV (FluMistÂ®) reduced the chance of influenza illness by 92% compared with placebo. In a study among adults, the participants were not specifically tested for influenza. However, the study found 19% fewer severe febrile respiratory tract illnesses, 24% fewer respiratory tract illnesses with fever, 23-27% fewer days of illness, 13-28% fewer lost work days, 15-41% fewer health care provider visits, and 43-47% less use of antibiotics compared with placebo.
Who can be vaccinated with the nasal-spray flu vaccine LAIV (FluMistÂ®)?
Who should not be vaccinated with the nasal-spray flu vaccine LAIV (FluMistÂ®)?
- People less than 2 years of age
- People 50 years of age and over
- People with a medical condition that places them at high risk for complications from influenza, including those with chronic heart or lung disease, such as asthma or reactive airways disease; people with medical conditions such as diabetes or kidney failure; or people with illnesses that weaken the immune system, or who take medications that can weaken the immune system.
- Children <5 years old with a history of recurrent wheezing
- Children or adolescents receiving aspirin
- Pregnant women
- People who have a severe allergy to chicken eggs or who are allergic to any of the nasal spray vaccine components.
- People with a history of Guillainâ€“BarrÃ© Syndrome (a severe paralytic illness, also called GBS) that occurred after receiving influenza vaccine and who are not at risk for severe illness from influenza should generally not receive vaccine. Tell your doctor if you ever had Guillain-BarrÃ© Syndrome. Your doctor will help you decide whether the vaccine is recommended for you.
Should the nasal-spray flu vaccine LAIV (FluMistÂ®) be given to patients with chronic diseases other than those specifically listed above?
Can the nasal-spray flu vaccine LAIV (FluMistÂ®) be given to patients when they are ill?
The nasal-spray flu vaccine LAIV (FluMistÂ®) can be given to people with minor illnesses (e.g., diarrhea or mild upper respiratory tract infection with or without fever). However, if nasal congestion is present that might limit delivery of the vaccine to the nasal lining, then delaying of vaccination until the nasal congestion is reduced should be considered.
Can people receiving the nasal-spray flu vaccine LAIV (FluMistÂ®) pass the vaccine viruses to others?
In clinical studies, transmission of vaccine viruses to close contacts has occurred only rarely. The current estimated risk of getting infected with vaccine virus after close contact with a person vaccinated with the nasal-spray flu vaccine is low (0.6%-2.4%). Because the viruses are weakened, infection is unlikely to result in influenza illness symptoms since the vaccine viruses have not been shown to mutate into typical or naturally occurring influenza viruses.
Can contacts of people with weakened immune systems get the nasal-spray flu vaccine LAIV (FluMistÂ®)?
People who are in contact with others with severely weakened immune systems when they are being cared for in a protective environment (for example, people with hematopoietic stem cell transplants), should not get LAIV (FluMistÂ®). People who have contact with others with lesser degrees of immunnosuppression (for example, people with diabetes, people with asthma taking corticosteroids, or people infected with HIV) can get LAIV (FluMistÂ®).
The nasal spray (also called LAIV or FluMistÂ®): The viruses in the nasal-spray vaccine are weakened and do not cause severe symptoms often associated with influenza illness. (In clinical studies, transmission of vaccine viruses to close contacts has occurred only rarely.)
In children, side effects from LAIV (FluMistÂ®) can include:
- runny nose
- muscle aches
In adults, side effects from LAIV (FluMistÂ®) can include
- runny nose
- sore throat
When should the nasal-spray flu vaccine LAIV (FluMistÂ®) be given?
Flu vaccination should begin as soon as vaccine is available and continue throughout the influenza season, into December, January, and beyond. While seasonal influenza outbreaks can happen as early as October, most of the time influenza activity peaks in January or later.
How often should the nasal-spray flu vaccine LAIV (FluMistÂ®) be given?
One dose of LAIV should be given during each influenza season. Children ages 2 through 8 years of age who are getting vaccinated for the first time and therefore require two doses for optimal immune response should receive the two doses at least 28 or more days apart.
Can people who received inactivated influenza vaccine (the flu shot) last year get the nasal-spray flu vaccine LAIV (FluMistÂ®) this year?
Yes, people who got inactivated influenza vaccine (the flu shot) last year can get the nasal-spray flu vaccine LAIV (FluMistÂ®) this year.