An additional 11 people have been infected with bird flu in Vietnam and about eight of them have died, though the cases have yet to be reported officially by local health authorities, according to a person familiar with the matter.
The cases add to the official death toll of 46 people, including 33 in Vietnam, the worst-hit nation, since the latest wave of cases of bird flu emerged in 2003.
The new cases also are fuelling concern about the reliability of statistics regarding the extent of the flu –especially data from Vietnam. In a separate bird-flu development, seven people who tested negative for H5N1 avian influenza in HCM City in January were later found to have the virus when their samples were retested. Some of them also died.
The above report identifies serious under-reporting of cases in Vietnam. The sudden halt of reports on human cases in Vietnam just before Tet was suspect. Many patients were hospitalised with symptoms, but not confirmed. The same was true of patients who died. It is not clear if these patients are included in the 11 unreported cases.
This report also indicates some of the false negatives died. Some or all of these cases were atypical, and the 7 false negatives only represented about one-third of the samples to be tested in Japan. Since all of these samples were from the south, it is not clear if similar numbers of false negatives are being generated from atypical cases in the north. These cases appear to be in addition to the Thai Binh cases.
The failure to report these cases in Vietnam raises concern that similar non-reporting is happening in Thailand, Cambodia, and Indonesia. Thailand has reported negative results on highly suspect patients, including at least one who was influenza A positive. Vietnam has said that its cases were complex, as were cases in Cambodia, suggesting more human infections. Indonesia has had H5N1 and H7N1 infections for at least 2 months, but has not reported any of the poultry infections to OIE.
Thus there are surveillance deficiencies in testing of cases, sensitivity of the assay, and reporting of results. The widespread problems cast serious doubt over the capability of any WHO containment plans.