A study from the Walter Reed Army Medical Center looked at the effectiveness of half-dose flu shots… and found that they are often just as effective as full doses.
The researchers worked with more than a thousand subjects between the ages of eighteen and sixty-four. Participants were chosen at random to get a half-dose or a full dose of the influenza vaccine.
After the shots were administered, antibody levels in the blood were adequate to protect against the flu in men and women of all ages. Researchers pointed out that full doses of the flu vaccine produced a stronger immune system response, but the half-doses were still enough to protect against the disease.
This means that it may be possible to stretch flu vaccine supplies by giving half doses — giving more people lower doses instead of giving fewer people full doses.
However, women and people under the age of fifty responded best to the lower vaccine doses (by producing more flu antibodies). So experts think the half-doses may be best reserved for adults under fifty. Adults in their sixties and beyond tend to be more vulnerable to the flu and complications related to the flu, and may need the immune system boost of a full dose more than a younger adult. More research is planned to see if lower doses will be adequate for older adults.
In the 2008-2009 flu season, less than one third of adults in the United States have chosen to get a flu vaccine according to a survey from the Rand Corporation. Slightly more than half of the adults surveyed planned to skip the flu shot this year, for various reasons. Some said they didn’t have time; others felt they just didn’t need it.
The U.S. Centers for Disease Control recommend that eighty-five percent of the American population get the flu vaccine — especially children, the elderly, and those who are susceptible to the flu.