The trial of an anti-influenza vaccine in human volunteers has been postponed for another three days after September 21, after a test with guinea pigs found one had developed infection in its lungs, the Government Pharmaceutical Organisation said yesterday.

Wichai Chokewiwat, chairman of the GPO's executive board, said the postponement was needed to wait for confirmation from experts examining infection in the lungs of one of 12 guinea pigs injected with the prototype serum. "[It's doubtful if] the infection resulted from the serum, but we are working to see what caused it," he added.

The examination will be continued at Chulalongkorn University's Faculty of Veterinary Science which is expected to determine the cause of the infection by September 23.

Of the first batch of 24 volunteer candidates for the human trial, two were selected on Wednesday out of four applicants. Wichia said he expected all 24 candidates to be available by September 24, when the human trial was scheduled to begin.

Meanwhile , a small 2009 influenza outbreak in Nan province has left 135 people ill, including a twoyearold baby, but caused no fatalities.

Most patients are Hmong people living in two villages in Muang province. They were screened and examined out of a total of 3,000 people in a recent investigation. This is a new outbreak following an earlier one which saw 71 people infected and treated.

Of 135 patients detected in the latest examination, 24 are being treated at Nan hospital while the remainder, with less severe symptoms, are at local public health offices.

The provincial public health office was conducting an awareness campaign in areas where the majority of Hmong people live to educate them further about preventive measures.

In the earlier outbreak, most of the 71 patients were women, and 55 students at secondary and university levels.

--The Nation/ANN