"If this pattern continues, an upsurge in cases could be anticipated starting in late 2006 or early 2007," the report said, adding that further analysis was needed. "Moreover, the widespread distribution of the H5N1 virus in poultry, and the continued exposure of humans suggest that the risk of virus evolving into a more transmissible agent in humans remains high."
The report stated that children and young adults were the most vulnerable to both infection and death from exposure, and identified three peaks in human infections since 2003, all during the spring and winter seasons of the Northern hemisphere. WHO medical officer Dr. Fred Hayden said there was evidence of the disease having an "environmental hardiness" that allowed it to thrive during colder months, leading to the spike in winter cases noted by the report.
Along with the evidence of increased vulnerability among younger populations, the WHO discovered that more than half of the infected patients died five days after hospitalization, just nine days after symptoms were first noticed.
A common problem noted in the report was a lack of shared information among affected countries, leading to holes in data and results. Hayden said more data sharing was imperative to combating the bird flu threat.