Gregory A. Poland, M.D. (LINK) answered this question with the wimpy “possible” word yet then explains plausibility without using the word.

Dear Mayo Clinic,  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? Were problems discovered with that method? It seems that it would be an efficient way to give flu shots, for instance, in a really short time.

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.

(So jet injectors weren’t discontinued in the general population until about 2003?)

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. HIV can lead to acquired immunodeficiency syndrome (AIDS) — a chronic, life-threatening condition caused by damage to the immune system. Hepatitis can cause chronic inflammation of the liver and lead to serious liver damage.

image: VA Veterans born in 1954 had the highest infection rate at 18.4 percent.

 

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,

STOP–he hadn’t heard about the widespread veteran/military outbreaks by 2008?  But he doesn’t claim that NO outbreaks occurred via 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.

From his bio: “Dr. Poland’s research has been continuously funded by the National Institutes of Health since 1991.”  He wants to provide information yet not bite the hand that feeds his lab–leaving us to read between the lines. The takeaway is that the risks of jet injectors are “no longer acceptable” but no pointers to actual evidence upon which his opinion is given is provided.