One shot of swine flu vaccine enough for adults

A total of 240 healthy adults aged 18-64 were evaluated for the study at a single center in Australia. They were randomly divided in two separate groups. Each group was to be treated with a different dose of swine flu vaccine.

The first group was given a standard dose of 15 micograms, whereas the second group had a 30 microgram dose of the vaccine.

Three weeks later, both groups were given a second shot of swine flu vaccine. After that, blood samples of all the volunteers were collected to scrutinize the results.

Findings show one shot suffices
The finding showed that a single 15 micorgrams dose of the H1N1 vaccine was able to produce the required immunogenic response in the adults with "mild to moderate" side effects.

According to a statement issued by the CSL Ltd, “Over 95 per cent of participants receiving the single 15 mcg dose of the vaccine achieved antibody levels that correlate with the prevention of influenza infection."

The researchers confirmed that there were no deaths or serious side effects. The most commonly reported side effects were mild to moderate symptoms like headcahes, pain at the injection site etc. that are similar to seasonal flu symptoms.

CSL Chief Scientific Officer Dr Andrew Cuthbertson said, "The preliminary data obtained from this initial study show a promising result which gives us confidence that a vaccination program can be successfully carried out in adults using a single standard dose of the H1N1 vaccine."

Anthony S. Fauci of the National Institutes of Health, which is leading the American effort to develop an H1N1 swine flu vaccine, said, "This is very good news. If you needed two doses, that would be a major strain on vaccine supplies nationally and globally."

Children might need two shots
There are still other groups like children, older people and adults with chronic health conditions who might need two shots of the swine flu vaccine because they are more vulnerable to the influenza viruses.

However, Cuthbertson said that the company is also in the process of conducting other studies to see how children and older adults respond to one shot of the swine flu vaccine.

Around 45 million swine flu vaccines would be distributed in U.S. in mid-October. After that about 20 million more doses are expected to become available every week, according to the health officials.

Groups more likely to get infected with swine flu, like pregnant women, people in contact with infants, medical personnel, people between the ages of six months and 24 years, would be the first ones to get the vaccine shots, as recommended by the U.S. Centers for Disease Control and Prevention (CDC).

The preliminary version of the study is published in the New England Journal of Medicine.