Bird flu vaccine offers protection above 90%, immune response good

Bhopal laboratory is now studying the duration of protection
# Vaccine tested for safety, other parameters
# Little chance of bird flu after vaccination

CHENNAI: The development of an avian influenza vaccine by the Bhopal-based High Security Animal Disease Laboratory brings India on a par with China, Pakistan, Indonesia and Thailand. The vaccine, which uses killed H5N1 virus, can be used during a H5N1 bird flu outbreak, says H.K. Pradhan, Joint Director of the laboratory.
The immune response is good and the protection offered by the vaccine has been found to be above 90 per cent. The laboratory is now studying the duration of protection. “According to the literature, the immunity [protection] can last up to six months,” says Dr. Pradhan. It can be further increased with a booster dose. This aspect is being investigated.
The vaccine has been tested for safety, dosage, adjuvant and the route of inoculation. “We found the intra-muscular [route] to be better.” There is little chance of bird flu occurring after vaccination as the vaccine uses a killed virus to elicit good immune response.

Homologous vaccine

The vaccine developed is a homologous one. It is considered superior to the heterologous vaccine, in which other viruses similar to H5N1 are used to control the spread of the virus.
The vaccine was developed in a short duration because the laboratory has been working on bird flu for the last six years. The Indian Council of Agricultural Research entrusted the job to the laboratory after the first outbreak in India this February and it was completed 10-15 days ago.
“We had the viruses collected during this year’s outbreak and the cell lines taken five years ago,” says Dr. Pradhan.
The vaccine can be used immediately after an outbreak to control the spread of the virus as well as for vaccination in anticipation of an outbreak. However, vaccination before an outbreak is generally not advisable as the vaccine has its own limitations.
Ideally, poultry in a five-km radius of the place of outbreak has to be killed and vaccination done on birds in a 5-10 km radius or more.
“This is called the ring vaccination.”
The cost and the licensing of the technology for commercial production are yet to be worked out, says Dr. Pradhan.

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