Flu vaccine is a little like liquid gold. at least, this year, with the huge flu vaccine shortage that’s affected the U.S., even those who should get the flu vaccine aren’t getting it. But now there’s new research to show that the limited supply can be stretched if the flu vaccine is given in a different way.

The study, released early in the New England Journal of Medicine, compared giving the flu vaccine intradermally, or into the skin, rather than the traditional way, which is giving it deeper into the muscle. The amount of flu vaccine given into the skin is 40% of the typical dose i.e. less than half the amount.
The research found that overall, the intradermal dose is overall is just as effective.
Dr. Stephen Baum, a flu expert at Beth Israel Medical Center in New York, says, “The results in vaccinating people over 60 were not very good. And one runs the risk of under-vaccinating the entire high risk population as opposed to vaccinating fewer of the high risk population but vaccinating them appropriately.”
The study looked at young people, those between the ages of 18 and 49. It found that the immune response--the immunity the body gets from the vaccine--was perhaps even greater with the smaller dose given into the skin than the larger intramuscular dose. This is important, because one study showed that this flu vaccine dose is effective in the older healthy group as well. As we get older, our immune response to the vaccine wanes, making us more susceptible.
So, this could be a significant find for those most at risk.
The flu remains a major health problem in the United States. Each year, there are 36,000 deaths and 200,000 hospitalizations. 90 percent of the deaths occur in those older than 65 years of age. The CDC has urged those groups most at risk get the flu vaccine in favor of others. These include healthy persons over 65, children 6-23 months of age, and adults and children with chronic conditions, such as asthma, heart and lung disease, and diabetes, pregnant women and nursing home patients.
The dermis contains copious amounts of cells called dendritic cells. These are cells that show enemy substances to the immune system to get it to respond and fight off the danger and destroy it. The dendritic cells are showing the flu vaccine to the immune system. So when the immune system encounters the flu itself, it can fight it more easily.
Dr. Baum states, “I think there will be and is a reluctance to move in that direction this year with this flu vaccine, and again most of the flu vaccine that was available has already been given out. So it’s a little like locking the barn door after the horses have left.”
This approach of injecting the flu vaccine into the skin is not yet FDA approved.

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