United States Flu Deaths Increase 150 Percent in 2003
Recombinomics Commentary
March 1, 2005
>> deaths from flu and pneumonia fell a combined 3.1%. The CDC said a large decline in pneumonia deaths offset a 150% increase in influenza deaths in 2003. <<
A 150% increase in influenza deaths in the United States in 2003 appears to be significant. This increase is masked by combining influenza with pneumonia deaths. The increase in deaths may be due in part to the early start of the 2003 / 2004 season. Many childhood deaths were in media reports at the end of 2003. These combined with the deaths from the 2002 /2003 season, which peaked in February, may have contributed to the 2003 increase.
The human flu vaccine selection for 2003 / 2004 was controversial. The Fujian strain of H3N2 had already begun to emerge in Asia in 2002. It was already in the United States in early 2003 (the Fujian-like vaccine isolate A/Wyoming/3/2003 was isolated February 13, 2003). The 2003 /2004 vaccine contained A/Panama/2007/99, which was used for the 5th year in a row and offered sub-optimal protection against Fujian like H3N2. The Fujian strain accounted for 88% of the isolates subjected to antigenic characterization in 2003 / 2004. . Thus, Fujian was circulating in the US for all of 2003 and it was not included in the human vaccine until the 2004 / 2005 season.
H3N2 can change rapidly as demonstrated by the emergence of Fujian in 2003 / 2004, which has been replaced by A/California/7/2004 in 2005. The emergence of California/7 in the US has been associated with a spike in media reports of students dying suddenly from meningitis and myocarditis. Combining influenza and pneumonia deaths could also mask the meningitis and myocarditis deaths this season.
The CDC report seems to have identified an emerging influenza problem in the United States, which may have been compounded by the selection of Panama for the 2003 / 2004 vaccine and the shortage of the 2004 / 2005 vaccine (containing Fujian).
A/California/7/2004 is spreading and evolving rapidly worldwide, and may cause additional problems next season. There is the potential for a shortfall in human vaccine again, coupled with the possibility that further evolution of H3N2 may diminish the effectiveness of next year's human vaccine.
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