Mutating virus calls for more changes

Thursday, November 01, 2012

Hong Kong is likely to change its bird flu vaccine for poultry more regularly, as the H5N1 virus keeps on mutating, according to veterinarian and epidemiologist Howard Wong Kai-hay.
Wong helped test the mainland-developed Re-5 vaccine on two Hong Kong farms in early November 2010. The government has decided to use its latest version, the Re-6, from later this month in the fight against bird flu.
"Re-5 and Re-6 are identical apart from the fact that the antigen, the viral seed, is different," Wong said.
"In terms of its production and quality control all that is basically the same. Like the human flu vaccine, you just change the seed each year to match the strain."

Since 2003, Hong Kong has been using the Intervet Nobilis H5N2 vaccine against H5N1 in poultry, as part of bird flu prevention measures.
"Almost 10 years down the line the virus has changed quite a lot," Wong said.
The Harbin Veterinary Research Institute in the mainland developed the Re-5 vaccine three years ago and earlier this year came up with an updated version, Re-6, he said.
The Intervet vaccine's effectiveness is becoming less effective as the virus mutates.
The Re-6 vaccinewill be used at Hong Kong's 30 chicken farms.
Some 1.2 million chickens produced at the farms in three-month cycles will have to be vaccinated at eight days old and then a month later.
"They will be then be bloodtested before sending to the market to ensure that their antibody levels are sufficiently high to protect them," Wong said.
The first batch of poultry vaccinated with Re-6 will be ready for the Lunar New Year.
H5N1 first hit Hong Kong in 1997, killing six out of 18 people infected.
 MARY ANN BENITEZ
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