WHO: Flu Virus Still Poses Risk Through MutationThe H1N1 flu virus continues to threaten public health, and could mutate into a more virulent form that can be expected to go around the world up to three times, says the World Health Organization.
The impact of any pandemic would range from a mild illness in countries with strong health programs to a devastating sickness in nations with weak health systems, shortages of drugs and poorly equipped hospitals, WHO says.
The H1N1 virus, also known as swine flu, "appears to be more contagious than seasonal influenza" and practically the whole world lacks immunity to it, the WHO states in a report Assessing the Severity of an Influenza Pandemic."
Ten percent of those infected with the strain in Mexico and the United States needed to be admitted to hospitals, a rate much higher than for seasonal flu, which kills up to 500,000 people worldwide each year, says Nikki Shindo, a medical officer of the WHO's clinical team overseeing the global influenza program.
"This is clearly different than what we see from seasonal influenza," Shindo told reporters on Tuesday. With most patients recovering from H1N1 with simple steps like hydration, and without any drug treatment, the situation still raises questions about the rush to stockpile and prescribe antivirals to treat the disease.
WHO will issue new guidance recommending that Tamiflu and other antiviral drugs be used only for vulnerable patients, such as pregnant women and people with other health problems including diabetes and cardiovascular disease. "We will recommend to consider the use of antivirals for high-risk groups or the group of people at increased risk, depending on the availability," Shindo says.
WHO's numbers show that 5,251 people have been infected with H1N1 flu in 30 countries. The virus has caused mild flu-like symptoms such as nausea, fever and diarrhea in most patients. Some infected patients don't even show symptoms. But flu strains mutate frequently and unpredictably and "the emergence of an inherently more virulent virus during the course of a pandemic can never be ruled out," WHO says.
The 1918 influenza pandemic that killed tens of millions of people began mild and returned within six months in a much more deadly form. The 1968 pandemic began relatively mild, with sporadic cases prior to the first wave and remained mild in its second wave in most countries.