Q: I remember we used to get vaccines and other shots using an air gun, and lots of people could get shots quickly. I haven’t seen this done for a long time. Why?
A: Using an air gun — also called a jet injector — is a fast way to deliver vaccines. But jet injectors were discontinued for mass vaccinations about five years ago because of possible health risks.
A jet injector uses high pressure to force a vaccine or other medication through a person’s skin. Their speed made jet injectors very efficient, so many people could be vaccinated quickly. They were often used in the military. Although they weren’t pain-free, jet injectors didn’t involve needles. The result was less discomfort than a needle injection, and they caused less anxiety in people who were afraid of needles.
In some cases, however, jet injectors could bring blood or other body fluids to the surface of the skin while the vaccine was being administered. Those fluids could contaminate the injector, creating the possibility that viruses could be transmitted to another person being vaccinated with the same device.
Of particular concern were viruses transmitted by blood, such as human immunodeficiency virus (HIV), hepatitis B and hepatitis C.
Greater awareness of these diseases and other blood- borne illnesses led to increased scrutiny of ways they might be spread.
Although no widespread outbreaks of these diseases were caused by jet injectors, the risk of blood and body fluid contamination of the equipment made jet injectors no longer acceptable for vaccinations.
Instead, most vaccines now are administered by needle injection, typically in the arm for adults and in the thigh for children.
In the case of the flu vaccine, another option that became available about three years ago is a nasal mist. All it takes is one spray in each nostril. It’s easy, quick and painless. No needles are involved.
This method has limitations, though. The nasal spray vaccine contains a low dose of weakened live virus. If a person’s immune system is severely suppressed due to illness or medical treatment, the live virus could, theoretically, cause the flu in that person. Also, the flu vaccine nasal spray appears to be less effective than needle injection (flu shot) in people 50 and older. For these reasons, the nasal spray is only approved for healthy people ages 2 to 49.
The flu shot is approved for people 6 months and older. Because the viruses in the flu shot aren’t live, it can’t cause you to get the flu but it will enable your body to develop the antibodies necessary to ward off influenza viruses.
Mayo Clinic recommends that everyone get the flu vaccine. Although people tend to think of influenza as a minor illness, it can cause pneumonia and lead to hospitalization, particularly in high-risk groups.
Dr. Gregory Poland, Vaccine Research Group, Mayo Clinic, Rochester, Minn.
Write to: medicaledge@mayo.edu, or Medical Edge from Mayo Clinic, c/o TMS, 2225 Kenmore Ave., Suite 114, Buffalo, N.Y., 14207; .
