This week the World Health Organization (WHO) declared the H1N1 “swine” flu pandemic [1] over, renewing calls that the organization should change the criteria for its six-level pandemic scale [2] or risk increased ambivalence toward public health threats.

The highest level of the WHO’s scale—which H1N1 reached in June of last year— simply indicates “human-to-human spread of the virus in two or more countries” in one of the WHO’s six global regions, and “in at least one other country in another WHO region.”

While relatively contagious, H1N1’s virulence—its ability to cause severe illness and death—paled next to the 1918 Spanish flu and even seasonal flu in the U.S. The 1918 outbreak is estimated to have killed between 50 and 100 million people, while as many as 56,000 people die from seasonal flu in the United States each year, according to the U.S. Centers for Disease Control and Prevention. H1N1 has killed roughly 18,500 people worldwide, according to the WHO.

As the outbreak leveled off late last year experts began to question the WHO’s classification criteria more fervently, while in March former U.S. public health official Dr. Henry I. Miller, writing in Forbes magazine, noted [3] that even seasonal flu meets the WHO’s definition of a pandemic.

The Associated Press, meanwhile, is reporting [4] that countries are throwing out millions of unused doses of H1N1 vaccine.

Experts told Security Management that the H1N1 outbreak exposed critical shortcomings in U.S. pandemic response that persist despite five years of planning and preparation launched in response to the H5N1 “avian” flu:

• Pre-H1N1 plans were based on preventing outbreaks overseas from entering the United States. However, by the time U.S. public officials became aware of H1N1’s outbreak in Mexico, it was already in the U.S.
• The United States still lacks the capability to track incidence and mortality in large-scale outbreaks—statistics are simply estimates based on a small sampling of hospitals and public health labs.
• Mass production and delivery of pandemic vaccine still takes months from the start of an outbreak.
• The U.S. public health sector failed to communicate the safety of the H1N1 vaccine amid growing public debate about the safety of vaccines in general. The H1N1 vaccine was nearly identical in composition to seasonal flu vaccine, which is known to be safe.

(Read more about lessons learned from the H1N1 pandemic in “Pandemic Lessons Learned [5]” in the Homeland Security department of February’s Security Management.)

The WHO noted that the H1N1 virus continues to infect people worldwide, but at post-pandemic levels.

The deadly yet rare H5N1 threat still persists as well. H5N1 shows a high rate of mortality in humans—roughly 50 percent—but as yet it rarely passes from birds to humans, and has not clearly demonstrated a capability for human-to-human transmission.

♦ Photo by The Truth About.../Flickr [6]

Thumbnail: