At the request of the Vietnamese Ministry of Health, World Health Organization (WHO) sent a team of international experts to Viet Nam last week to assess laboratory and epidemiological data on recent cases and determine whether the present level of pandemic alert should be increased.
Team members were drawn from institutes in Australia, Canada, Hong Kong SAR, Japan, the United Kingdom and the United States of America having extensive experience in the testing of avian influenza viruses in human clinical specimens.
The team completed its work on Wednesday and submitted its preliminary findings to the government. The team found no laboratory evidence suggesting that human infections are occurring with greater frequency or that the virus is spreading readily among humans. The current level of pandemic alert, which has been in effect since January 2004, remains unchanged. Some reports now circulating suggest that WHO has downgraded its assessment of the pandemic threat. These reports are unfounded. The experts were specifically asked to search for evidence that could substantiate concerns raised first at a WHO consultation of international experts held at the beginning of May in Manila. That consultation considered suggestive findings, largely based on epidemiological observations, that the H5N1 virus had changed its behaviour in ways consistent with an improved, though not yet efficient, ability to spread directly from one human to another. The specific epidemiological observations considered included milder disease across a broader age spectrum and a growing number of clusters of cases, closely related in time and place.