May 19, 2005 (CIDRAP News) – The World Health Organization (WHO) has significantly increased its tally of H5N1 avian influenza cases on the basis of information from Vietnam, bringing the total to 97 cases, including 53 deaths. The agency previously listed 89 cases with 52 deaths.
In announcing the numbers today, the WHO did not identify any of the added cases individually, but said Vietnam's Ministry of Health has been asked to provide data on individual cases.
The new tally implies that some confirmed cases have gone unreported by major news media. The numbers push the WHO's count above an unofficial count maintained by CIDRAP on the basis of both WHO numbers and media reports of confirmed cases. The unofficial count stood at 92 cases with 53 deaths before the new WHO announcement.
The new WHO numbers represent an overall case-fatality rate of about 55%. Until recently, the fatality rate had hovered in the 70% range.
A new WHO table of H5N1 cases breaks them down into three time periods: Dec 26, 2003, to Mar 10, 2004; July 19 to Oct 8, 2004; and Dec 16, 2004, to May 13, 2005.
In the latest wave of cases, Vietnam has had 17 deaths among 49 cases, according to the WHO, for a fatality rate of about 35%. Since December 2003, the country has had a total of 76 cases with 37 deaths, for a fatality rate of 49%.
Thailand has had 12 deaths among 17 cases, all of them occurring in the first two time periods. Cambodia's four cases—all fatal—have all occurred since mid-December.
May 19 WHO statement