A single shot vaccine is enough to protect school going children from swine flu, researchers in Australia have said.
The researchers — Dr Terry Nolan and colleagues from the University of Melbourne in Australia — were to publish their findings in the January edition of Journal of American Medical Association (JAMA), but released it online, ahead of schedule, because of its public health implications.
Across the world, school going children have borne most of the brunt of H1N1. Since they have no measurable immunity against the virus, most children under five have had to be hospitalised. Though developed countries have already started immunising their people, the generic version of swine flu vaccines are expected to reach Indian markets only by March 2010.
India is planning to procure roughly 15 lakh shots of swine flu vaccines from multinational pharmaceutical companies. These vaccines will be available in the country by January.
“The government won’t be able to immunise everybody. The imported vaccines are for doctors and paramedics who are handling H1N1 patients. The generic version of the vaccine, due to arrive in India in March, will be tested before being used on children and high-risk category patients,” said Dr VM Katoch, director general of Indian Council of Medical Research (ICMR), which is advising the government on vaccines and swine flu treatment.
The World Health Organisation (WHO) too, favours single shot vaccines. “Where national authorities have made children a priority for early vaccination, experts are advising one dose to as many children as possible over the age of 6 months and under 10 years,” the WHO said. The organisation believes that vaccines have so far proved safe for pregnant women and small children and the “benefits of vaccination outweigh the risks.”
Dr Nolan and colleagues assessed the effectiveness and safety of two doses of a H1N1 vaccine on 370 healthy infants and children between 6 months and under 9 years. The children were randomised into groups, and received a two-injection regimen 21 days apart in doses of 15-micrograms or 30-micrograms.
The researchers found that most of the adverse reactions to the vaccine were mild to moderate. But, the immune responses were strong. “Our findings suggest that a single dose 15-microgram vaccine regimen may be effective in children, and may reduce transmission of H1N1,” the authors said.
However, doctors from the National Center for Infectious Diseases, Centers for Disease Control and Prevention (CDCP), Atlanta, urged that the results be interpreted carefully.
“The immunogenicity data suggest that at least some children will be protected after a single 15-microgram dose, but the findings cannot be generalised to all children, which is why it is prudent to give two doses,” CDCP experts said.
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