Early testing of poultry vaccinated against bird flu in Vietnam shows more than 80 percent of the sampled birds developed at least some immunity to the H5N1 virus, but more tests are needed to determine the vaccine's overall effectiveness, officials said Monday. Some 7,600 blood specimens were taken randomly over the past month throughout the country, about a month after Vietnam's two-shot mass vaccination campaign ended, said Do Huu Dung, an official at the national Department of Animal Health.
He said initial test results showed about 86 percent of the ducks sampled had developed some level of immunity, compared to about 83 percent of the chickens tested. Animal health experts are expected to have a clearer picture of the vaccine's overall effectiveness after 42,000 more random samples are tested this year, Dung said.
However, officials say they believe country's mass vaccination of more than 120 million birds, which began last August, is helping to reduce the number of poultry outbreaks nationwide. Vietnam, which has been hardest-hit by bird flu, has not detected any new poultry outbreaks in more than a month. No human cases have been reported since November.
"The vaccination works," said Hoang Van Nam, deputy director of the national Department of Animal Health. "No outbreaks were reported in areas where poultry were given two shots of vaccine."
The last outbreak among poultry was reported in the northern province of Cao Bang bordering China on Dec. 17, Nam said, attributing the result to the vaccination campaigns and to strong political will. But Nam warned there was no room for complacency, reports the AP. N.U.
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