Alan Sipress - The Fatal Strain

But what if it’s a false alarm? “If you raise the level and you’re wrong,” Stohr thought, “you’ll be blamed.” The Vietnamese would be stigmatized. Their economy damaged. The move would spark waves of unnecessary panic worldwide, and WHO’s own credibility would suffer. Future warnings might be ignored.

“You make the decision based on the data you have in a responsible way,” he later explained. “You need to get ready to defend it. You need to get ready to take the blame.”

At that moment in mid-2005, the alert level was at level three, meaning the virus had succeeded in achieving no more than very limited human transmission. Based on the new information, WHO could hike the level to four or five, signifying greater human transmission and alerting the world that a full-blown pandemic, level six, was imminent.

An internal document written that same day suggested the situation might be even graver: “If the results are correct… this could be the signal that an influenza pandemic has begun.”

“Good morning, good afternoon, and good evening to everyone,” Stohr said as he opened the conference call at ten minutes past noon on Friday, June 10. His greeting was familiar to those who had sat in on his previous calls but the setting was not. He had summoned his staff to the WHO bunker, and they gathered around the large, circular conference table in the mezzanine overlooking the main floor of the SHOC. The command center offered a sophisticated communications network that could handle the large call while its secure doors assured that access to the session was kept strictly limited.

On the call were WHO officers from the Hanoi office and Manila regional headquarters. Also invited to participate were Dr. Nancy Cox, chief of CDC Atlanta’s influenza division, Dr. Roy Anderson, a senior epidemiologist at London’s Imperial College and chief science advisor to the British defense ministry, Dr. John Horvath, the Australian government’s chief medical officer, Dr. Masato Tashiro, head of virology at Japan’s National Institute of Infectious Diseases, and Dr. Kiyosu Taniguchi, chief of infectious-disease intelligence at NIID. Dr. Yan Li, the Canadian scientist, was also on the line.

They had all been supplied copies of the report detailing the test results from Vietnam. Now Stohr wanted their feedback. He said they would go in alphabetical order.

Anderson would have started, but he was running late. So Cox, the tough-minded virologist from the CDC, was first out of the box. Wasting no time, she went on the attack, calling the tests into question.

“The results I’m most concerned about,” Cox said, “are the antibody test.”

She and her colleagues at the CDC had previously done extensive work developing various tests for antibodies and had discovered that some of these techniques picked up false positives for H5N1. Some even purported to show evidence of the virus in specimens from U.S. blood donors who had never been within thousands of miles of an actual H5N1 outbreak, whether in people or birds. In particular, Cox was skeptical about the reliability of Western blot testing. To avoid misleading findings, the sensitivity and precision of this kind of analysis had to be calibrated using the results of other tests.

On the call, she grilled Li about his techniques in performing Western blot and interrogated him about whether he had used proper scientific controls to gauge the accuracy of his findings.

“Very limited controls,” Li acknowledged. He was already on his heels. “The number of controls is very low.”

Cox pressed on. She said the CDC had tested similar serum samples from Vietnam, and they’d all come back negative for virus antibodies. She called the rate of positives in Li’s test, or assay, “exceedingly high.”

“I really wonder if your assay is picking up false positives,” she continued. She urged that the samples be retested using a more respected technique for detecting antibodies, called microneutralization. “The serology is very much in doubt and must be repeated with another test in another lab,” she insisted.

“I understand the risks of Western blot,” Li responded defensively. He stressed that his findings were only preliminary. He admitted they might have overestimated the extent of infection in Vietnam.

Cox wanted everyone on the call to take a deep breath and think hard before rushing to conclude there was evidence of an emerging pandemic. So she continued to pound away, questioning the overall reliability of Li’s approach.

“The results are in question because they were obtained with an assay that hasn’t been validated,” she argued.

“I agree,” Li conceded, wishing his results had never been passed to the agency. “I didn’t even want that circulated.”

None of the other experts had yet weighed in, and already they could feel Li squirming on the other end of the line.

For a moment, he seemed to win a respite. The call shifted to a discussion of the genetic changes Li had detected and whether these were making the virus less lethal. He said that the mutations had been found in most of the human samples that his team analyzed. He suggested that either the virus was evolving into a less deadly form, or an entirely new flu virus was now circulating in Vietnam.

But he promptly came under fire again, this time from a new quarter. Anderson, the British epidemiologist, had joined the call and pushed Li on whether those mutations alone would determine the lethality of the virus. Anderson personally didn’t think so. He also noted that the analysis had examined only an “exceedingly small” number of samples.

Cox joined back in, suggesting that a whole series of genetic changes would be needed to alter the lethality, not just one. And even if these changes did make the virus less deadly in animals, as some scientists suspected, she was unconvinced these changes would do the same in people. She wasn’t even sure the mutations had occurred at all.

“The results need to be verified,” she said, repeating her refrain. “It’s quite possible they are true, but they need to be verified.”

Horvath, the Australian chief medical officer, now entered the fray. He wondered whether the researchers had tried to make sense of their highly unusual lab findings by comparing them with the actual experience of patients in the hospital.

“It’s difficult to understand, naturally,” Li offered meekly.

Then, abruptly, the tone changed. Having roughed up Li, the expert panel shifted gears and began to ponder what it would mean if he actually proved to be correct.

“The problem is serious, very urgent,” Anderson conceded. “We need access to information. It’s urgent that an independent lab confirms the changes.” But Vietnam might not share that sense of urgency, and Hanoi’s record of cooperation was poor. “It may be necessary to elevate the pandemic level to get the information,” Anderson suggested.

Stohr pressed the issue of whether to in fact raise the level. “How concerned should we be?” he queried.

“On face value, it’s a very serious report,” Horvath answered. “But it’s not sufficient to take action. I’d be concerned with raising the level of pandemic because it might shut Vietnam down.”

“We’d have to weigh that risk,” Anderson said. The move could be highly unpopular in Southeast Asia. He said the agency would have to weigh “the urgency to understand more versus the danger of upsetting the political balance.”

With time on the call running down, the experts turned to the third and final set of findings. These were the results of the PCR tests on the samples from the Thai Binh health-care facilities, which had revealed a 10 percent rate of infection. They were the most troubling findings. PCR was a more reliable test than Western blot.