Dec 3, 2009 (CIDRAP News) – The World Health Organization's (WHO's) top influenza expert said today it's too soon to judge whether the H1N1 influenza pandemic has passed its peak, though he acknowledged that cases are dropping in the United States and Canada.
"It's too early to say whether activity is peaking in the Northern Hemisphere, and it's not possible to predict what will happen in the spring," said Dr. Keiji Fukuda, special adviser to the WHO director-general on pandemic flu.
In response to questions, Fukuda said it's premature for the WHO to start formal discussions on whether the pandemic has crested. "In some countries there are still increasing infections, even though there are some countries, such as the United States and Canada, where infections are going down," he said.
Formal discussions on whether the pandemic is waning won't come until "sometime in 2010," he said.
Recent reports indicate that that the second wave of pandemic is ebbing in the United States and Canada. The latest report from the US Centers for Disease Control and Prevention (CDC), covering the third week in November, said physician visits for flu-like illness dropped for the fourth straight week. And the Public Health Agency of Canada said on Nov 27 that all provinces and territories had reached "a possible epidemic peak."
The evidence from Europe is less clear. Today's update from the European Centre for Disease Prevention and Control (ECDC) said H1N1 deaths increased by 6% last week, signaling a slower rise in mortality, as the toll had been nearly doubling every 2 weeks over the preceding 6 weeks.
In other comments today, Fukuda said the WHO has not calculated a case-fatality rate (CFR) for the pandemic, after a reporter noted that the CDC recently estimated the US CFR to be .018%.
Fukuda said CFR estimates depend today, as in past pandemics, mainly on gathering data on all deaths and then using modeling techniques to estimate how many were flu-related. "People don't count flu deaths on a one-to-one basis," he said.
"It's much too soon to have the kind of vital record health data that's typically used to model estimates of overall [flu] deaths," he added. "I think it'll take another 1 to 2 years after the pandemic to collect this kind of data and come up with estimates."
The WHO estimates that 150 million doses of H1N1 vaccine have been distributed in about 40 countries so far, Fukuda said.
Meanwhile, the WHO released a statement today to allay concerns it said have been voiced in the news media that experts on some of the agency's advisory committees have pharmaceutical industry ties that influence policy decisions related to the pandemic.
The statement says the WHO has historically collaborated with the pharmaceutical industry because efforts to improve health depend on access to effective and affordable medicines, vaccines, and diagnostics. The agency said it has many safeguards to identify and deal with potential conflicts of interest.
The statement also says public perceptions of the H1N1 pandemic have been strongly influenced by the 5-year history of worry about the deadly H5N1 avian influenza virus. "Adjusting public perceptions to suit a far less lethal virus has been problematic," the agency said. "Given the discrepancy between what was expected and what has happened, a search for ulterior motives on the part of WHO and its scientific advisers is understandable, though without justification."
In the briefing, Fukuda emphasized the necessity of WHO's collaboration with many partners, including private companies, though he didn't mention media criticisms.
"It's the private sector that makes vaccine," he said. "Most vaccine is not made by governments, but by companies in the private sector, both in developed and developing countries. It's this group which has unique knowledge of vaccines because they manufacture them. It's essential for public health to access this knowledge."
WHO statement on the use of advisory bodies in responding to the pandemic
Nov 30 CIDRAP News story "CDC: Flu activity eases, but child deaths still climb"