Questions raised about Vietnam's avian flu reports and testing

Mar 4, 2005 (CIDRAP News) – Vietnam, the country at the center of this year's avian influenza activity, may have two problems with its data on human cases: transparency in reporting and accuracy in testing.

The country has lapsed in its reporting of cases to the World Health Organization (WHO). More than a month passed without official reporting of cases, despite widespread media reports of several new cases, according to a story by the Canadian Press (CP) on Mar 1.

Ongoing monitoring by CIDRAP News also shows substantial discrepancies between official and unofficial numbers (see Case Count tables).

Because the WHO relies on official reports for its case counts and as the basis for advice to member countries, the lack of reporting has an impact, Dr. Klaus Stohr, director of the WHO's global influenza program, told the CP.

"The situation is that WHO has a request by its member states to provide proper risk assessment, to help other member states of WHO . . . in assessing what's going on in Asia and provide advice to other member states. And without this information, this is very difficult," Stohr said.

WHO officials had requested reports in person and in writing, the CP story noted. Those efforts appeared to be paying off on Mar 2, when Dick Thompson, communications officer in the Communicable Diseases Section of WHO in Geneva, told CIDRAP News by e-mail, "We understand that there is some movement and we will have an update shortly."

Vietnam is not the only country with reporting shortcomings. Indonesian farmers tallied more than 33,000 poultry deaths from avian flu during the past 2 months, the Jakarta Post reported today. Indonesia has not reported any new outbreaks to the World Organization for Animal Health (OIE) in several months.

Reporting can trigger difficult consequences. "Many countries find it difficult to report outbreaks of contagious diseases. These can impact trade and tourism, or it can injure their international standing or self-image," Thompson wrote.

The pattern of cases in Vietnam has not changed recently. Thompson commented, "The press reports suggest that the missing cases are sporadic. This would be a serious public health issue if there were a cluster of cases—that is not 15 isolated cases ranging over several weeks, but a single cluster of 15 cases, from one area, among casual contacts and health care workers. That doesn't seem to be the case in Viet Nam."

He criticized developed nations: "These are nations which can afford to help countries like Viet Nam. Right now, these Asian countries are sustaining enormous hits to their economies in the effort to fight [avian] flu. If they are successful, every nation will benefit by not having to confront a pandemic. Therefore, we believe that those nations which share the benefits of this fight should . . . help [poorer] countries which are largely managing on their own."

Reporting issues aside, Vietnam may face another hurdle in coping with avian flu: re-analysis of samples showed that some Vietnamese who had flulike symptoms but tested negative for H5N1 in Vietnam actually had the virus. The findings, which cast doubt on the sensitivity of Vietnam's H5N1 test, were described in a Feb 24 news story in Nature.

According to the story, samples from 11 recent avian flu case-patients in Vietnam, as well as samples from 90 patients who had suspected cases but tested negative for H5N1, were sent to the National Institute of Infectious Diseases in Tokyo. About a third of the samples had been tested there so far. Of those, seven that had tested negative in Vietnam were found to be positive, said Phan Van Tu, head of the microbiology and immunology department at the Pasteur Institute in Ho Chi Minh City.

Retesting in Vietnam then confirmed four of the seven positive results.

Tu said one reason for the discrepancy was that reagents in the original tests weren't mixed well and yielded unclear results. He added that the institute would use the more sensitive test that was used in Tokyo and improve technician training, according to the story.

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