WHO Maintains Level 5 Pandemic Alert Level

Emma Hitt, PhD

April 30, 2009

April 30, 2009 — After increasing the pandemic level to 5 last night, the World Health Organization (WHO) says that it will keep the pandemic level at phase 5 for the time being. No comment was made about whether an increase to phase 6 was imminent or inevitable.

Keiji Fukuda, MD, MPH, assistant director-general ad. interim for health security and environment at the WHO, discussed the pandemic level during a WHO media briefing today.

The WHO's phase 5 alert level is characterized by human-to-human spread of the virus into at least 2 countries in a single WHO region. The final phase, phase 6, indicates that a global pandemic is under way and is characterized by community-level outbreaks in at least 1 other country in a different WHO region in addition to the criteria defined in phase 5.

"We do not have any evidence to believe that the pandemic level should be raised to phase 6," Dr. Fukuda said, although he added that "I think it's fair to say that the situation continues to evolve."

He emphasized that the phase levels used by WHO are not a measurement of the epidemiology of the disease. "They are really a warning to countries and the global population to make preparations to reduce the health impact of the virus," he said.

According to Dr. Fukuda, the WHO Director General Dr. Margaret Chan raised the level from phase 4 to phase 5 last night due to spreading of the virus within affected communities. "In New York City, for example, we began to see the virus spreading out to the community and not just travel-related cases. It was on this basis that we made the judgment that this was now the time to increase the pandemic phase from 4 to 5."

As of 8:50 am EDT, the number of lab-confirmed cases of the H1N1 influenza strain totaled 236 cases, up from 148 cases yesterday. The largest increase was in Mexico, from 26 to 97 cases, probably due to increased testing of a backlog of thousands of specimens, he said.

"Cases are increasing in some countries, but appear to be holding steady in others, such as the United States," Dr. Fukuda said.

Roche, which manufactures oseltamivir (Tamiflu), in 2005 and 2006, donated 5 million treatment courses to WHO to support a rapid containment operation if WHO deemed that necessary. "At this point WHO has begun distributing Tamiflu to developing countries determined by WHO to be most in need of this kind of assistance, and Mexico has also received a portion of this stockpile," he said.

According to Dr. Fukuda, Roche has indicated that it is scaling up production of the drug and is working out the logistics for providing additional supplies.

The WHO has issued no travel restrictions, "because we do not believe that will slow the transmission down," Dr. Fukuda said. "If you are feeling ill, you should consider delaying travel and staying at home. If you are traveling and you become sick during that travel, it is important to seek medical attention while there," he said.

Peter Katona, MD, associate clinical professor of infectious diseases at the David Geffen School of Medicine at the University of California, Los Angeles, advised that clinicians should strive to understand the epidemiology of their particular geographic area so that they "can make effective decisions about how to treat patients. They should also assess the severity of a patient's individual case to determine the need for intervention such as an antiviral."

"Right now it doesn't look like this is a severe strain, at least in the United States, so I wouldn’t rush to give an antiviral to everybody that comes in with flu symptoms," he told Medscape Infectious Diseases.

Dr. Katona noted that oseltamivir was becoming harder to get because people are "starting to hoard it and trying to get prescriptions, which is not really what we want to do." He added that no resistance to these antivirals seems to have developed yet, but I "wouldn't be surprised if that happens with more and more use of these drugs."


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