Jan 25

Influenza epidemic doubles number of cases per hospital (Japan Times/Kyodo, Jan. 25, 2012):

An nationwide influenza epidemic is spreading, doubling the number of cases per hospital, according to data compiled through Tuesday by the National Institute of Infectious Diseases.

Over 90 percent of the cases this flu season are due to the Hong Kong influenza A virus subtype H3N2. The data marked the first epidemic in five years of the seasonal flu virus, which can cause encephalitis in infants and gravely affect the elderly, the institute said.

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Nov 09

25 patients and 8 staffs are suffering from influenza now

29 Oct., vaccinated against the flu
31 Oct., a man died(eighties)
2 Nov., 2 men died(sixties, nineties) a woman died(seventies)
4 Nov., a woman died(eighties)
5 Nov., a man died(eighties)

The above comments provide more detail on the H3N2 outbreak in a hospital in Akita, Japan that killed six patients in six daysThese patients had been vaccinated days prior to the deaths raising concerns that the timing of the vaccinations may have contributed to the fatal outcomes.

The trivalent vaccine is designed for use prior to infections.  The above timeline raises the possibility that the vaccinations were in response to the nosocomial outbreak.  Elderly patients typically have a poor vaccination response because of a decline immune system, and therefore may be more vulnerable to infections shortly after vaccination because their immune system is taxed by the three targets in the vaccine.  In the above outbreak, it is likely that all victims were infected by H3N2.  The H1N1 and influenza B in the vaccine wouldn’t help mount a response to the live H3N2.  Moreover, the H3N2 in the vaccine may also not help in the short or long term because the current H3N2 has evolved away from the H3N2 target and an emerging strain with low reactors has been defined by phylogenetic analysis.  This new strain has been seen in recent sequences from Japan. Low reactors produce a lower titer, which would significantly impact an elderly population because they typically produce a marginal response to influenza vaccinations.

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