The novel H1N1 influenza is now a full-blown pandemic, the World Health Organization said today, the first in 41 years.
“The scientific criteria for an influenza pandemic have been met,” WHO Director-General Margaret Chan, M.D., said in a Geneva press conference.
Those criteria include sustained community transmission in at least two regions of the world, but say nothing about the severity of the outbreak, Dr. Chan said.
Indeed, on the basis of available evidence, she said, the pandemic will be “of moderate severity.”
“The overwhelming majority of patients experience mild symptoms and make a rapid and full recovery, often in the absence of any form of medical care,” Dr. Chan said.
Although there have been 144 deaths, she said, “we do not expect to see a sudden and dramatic jump in the number of fatal infections.”
That said, Dr. Chan noted, influenza is highly variable and can “change the rules without rhyme or reason,” so a sudden increase in severity can’t be ruled out.
Agency officials added that the severity of a pandemic also depends on the population it attacks. In this case, poorer countries and those with a younger population might be harder hit, according to Keiji Fukuda, M.D., an assistant director-general of the agency.
The jump to phase six is no surprise, according to new CDC Director Thomas Frieden, M.D. “It was expected on the basis of the data,” he told a press conference today.
The main implication of the WHO declaration is that the virus is continuing to spread and is “likely here to stay,” he said.
But for the U.S., he said, there are few practical implications. “We have been acting as if it’s a pandemic for some time,” Dr. Frieden said, and no new initiatives are planned.
World-wide, WHO has had official reports of nearly 30,000 cases, Dr. Chan said, but that number is almost certainly an underestimate, since about half of those cases have been reported in countries — like the U.S. and Canada — with highly developed public health and surveillance systems.
The change to phase six of the agency’s pandemic preparedness scale was widely expected, as the disease continued to spread from its origins in North America.
UN officials were at pains earlier in the week, however, to emphasize that most cases of the disease are mild and that increasing the pandemic level would not mean the outbreak is causing more severe disease.
A change to phase six “does not mean that the severity of the situation has increased and that people are getting seriously sick at higher numbers or higher rates than they are right now,” Dr. Fukuda said.
Dr. Chan said it’s very likely that a second wave of the virus will hit northern hemisphere countries in the fall, and urged them to remain vigilant, even if the current outbreak appears to be waning, as it is in Mexico.
In the U.S., the CDC said, most areas of the country are seeing only a few cases of the flu, with the exceptions of New England and the New York/New Jersey region, where flu-like illness remains above baseline values.
For the U.S., Mexico, and Canada — the countries hardest hit so far — the change to phase six means relatively little, a cross-section of experts agreed.
The declaration “merely confirms the obvious — that there is community transmission worldwide,” said Pascal James Imperato, M.D., of the SUNY Downstate Medical Center in New York.
“The raising of the pandemic level is a response to statistics,” said Richard Bradley, M.D., of the University of Texas Medical School in Houston. “For us in the U.S. there is no major significance or effect of the level being raised.”
In essence, he said, “it’s been pandemic all along, nothing is different. Don’t panic. The virus is still mild.”
“Not much, if anything, will change in the U.S.,” agreed William Schaffner, M.D., of Vanderbilt University School of Medicine in Atlanta.
“The U.S. public health structure already is performing enhanced surveillance for influenza throughout the summer,” he said, and hospitals, health departments, and other agencies are revising their pandemic plans.
But, he said, other national governments, especially in the developing world, may respond by enhancing their own planning.
“This is not a surprise,” said Christian Sandrock, M.D., of the University of California Davis School of Medicine, but he said the announcement may lead to better planning for the fall flu season “when we will see these cases in higher numbers.”
Dr. Sandrock said “money and planning from a government level will be improved with this declaration,” although he cautioned it could also cause “misunderstanding and panic.”
Julie Gerberding, M.D., the former director of the CDC, said the main actions suggested by the WHO under phases five and six are identical. But she noted that some countries may have tied their national responses to the different levels, so that going to phase six might lead to “significant local, regional, or national impact.”
But she agreed with other experts that “technically, we have been in phase six for some time.”
Stephen Morse, Ph.D., of Columbia University Medical Center, said the declaration is “essentially just acknowledging the facts that already exist on the ground.”
Like other experts, he cautioned that the term “pandemic” says nothing about the severity of the disease. “As far as I can tell, nothing has really changed dramatically since yesterday,” Dr. Morse said, adding that WHO held off so long to avoid what he called “perceptual” impacts.
That was probably the right decision, according to Philip Alcabes, Ph.D., of CUNY Hunter College in New York City. Dr. Alcabes is the author of Dread: How Fear and Fantasy Have Fueled Epidemics from the Black Death to Avian Flu.
“WHO was right to be cautious about raising the threat barometer to six,” Dr. Alcabes said.
But he said officials were being disingenuous when they said the delay was to avoid panicking the public.
“In general, people don’t panic about disease outbreaks,” Dr. Alcabes said. “The problem, of which WHO is abundantly aware, is that governments do panic.”
In other words, he said, governments often use the threat of disease as a rationale for political acts, such as the “unnecessary” Chinese quarantines or the slaughter of pigs in Egypt.
“In the context of other disease outbreaks, we’ve seen border closings, travel warnings, and nutty investigations of airline passengers,” he said. “All of that is politics, masquerading as public health.”
In the long run, he said, WHO should abandon the pandemic-threat scale altogether.
“That day is probably a ways off, though,” Dr. Alcabes said. “It will take political will on the part of a lot of countries’ governments — including ones that still imagine they can ward off disease by shutting borders (or killing pigs).”
On the other hand, the move to phase six puts “everyone on the same page,” according to Gregory Poland, M.D., of the Mayo Clinic in Rochester, Minn., with the goals of:
* Communicating to individuals, health systems, and governments that there is a pandemic and altering them to be ready for potentially rapid changes and to put plans into action
* Enabling global communication and coordination
* Allowing vaccines, antiviral drugs, masks, medical assistance, and other resources to be moved to poorer countries
Among other things, the move puts pressure on governments and health officials to get ready, Dr. Poland said.
