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to Windwalker. I didn't put it together that this Barry was the same one who wrote the book. ----------------------------------------------
The Epidemiological Picture
* No good sense of RO, 4 studies give 4 different rates.
* Incubation period is unknown. Reasonable assumptions have been made that incubation is comparable to seasonal influenza, but data from Spain suggests incubation is longer.
* Case mortality has been estimated from 0.1% to 0.4%
* The number of cases worldwide is impossible to ascertain= We had widespread community illness before CDC posted a single confirmed case in Seattle. More recently, the New York City Health department estimated that cases reached several hundred thousand in its jurisdiction.
* 6 to 9% of unvaccinated adults ages 18 to 64 showed antibody reactive against novel H1N1, while 33% of those over 60 had antibody
* After vaccination with the trivalent seasonal flu, which includes a component of the already-circulating H1N1 virus, 7% of ages 18 to 40, 25 percent of ages 40 to 64, and 43 percent of those under (Over?) age 60 had protective antibody against novel H1N1.
Antivirals and Vax
* As of mid-June, no resistance to neuraminidase inhibitors has been reported for novel H1N1. But more than 90% of samples of both H3N2 and previously circulating H1N1 have developed resistance.
* egg-based production will supply the overwhelming bulk of the vaccine, cell-based production will supply some, and contracts for VLP monoclonal antibodies, and other technologies have also been signed.
* In a best-case scenario, the virus will require no more antigen than a seasonal influenza vaccine, only a single dose will be needed to provide protection, and adjuvant will cut in half the amount of antigen needed. If all that occurs, sufficient vaccine could be available to protect the entire U.S. population by October 2009.
* In a worst-case scenario, the virus will grow more slowly than anticipated, more antigen will be required to generate an immune response than for seasonal influenza, and 2 doses will be required. In that case, it could take a year or more to produce enough vaccine for the entire population.
* Only 31% of the vaccine needed is produced in the US
* For influenza, a good vaccine is 70% effective and a great vaccine is 90% effective. In the 2007-2008 flu season, the vaccine was only 44% effective. Producing a highly effective vaccine for a new virus, which may be less stable than seasonal influenza, should be more difficult than for ordinary influenza.
Recent Non-Pharmaceutical Interventions and International Actions
* No positive conclusion as to the effectiveness of school closings. Regarding 1918: there is solid contradictory evidence that schools did not play a significant role in transmitting infection. One speculative explanation for this contradictory data is that the immune systems of adults and children were equal. Because the 1918 virus came directly from birds, no one had been previously exposed to it, and by 1920 everyone old enough for school had been exposed.
* NPI: It is not clear whether these measures had any effect. In Mexico, the decline in compliance with mask usage does not portend well for sustaining an NPI.
Waves and Patterns from Past Pandemics
* Discusses 1899, 1918, 1957, 1968. This part should be read in its entirety; too much info to summarize.
The Future of Novel H1N1
* The novel H1N1 virus seems thus far to be following the pattern of 1889, 1918, and 1957 and it seems highly likely that it will return in full flower.
* If the virus is fully adapted to and efficient at infecting humans, this would occur soon, possibly during the influenza season in the southern hemisphere or possibly a few months later in the northern hemisphere.
* If the virus needs further adaptation to become fully efficient in infecting humans, that could be delayed, quite possibly a year or two later. It seems very unlikely that this virus will peter out.
* The most disturbing information molecular biology has provided is genetic markers predictive of adaptation to humans are not currently present in the [H1N1] viruses, suggesting previously unrecognized determinants could be responsible for transmission.
* This suggests two things: 1. this virus may have other things to teach us; 2. we do not know the whole story of how influenza becomes transmissible from human to human, so our monitoring of H5N1 for these markers is incomplete.
* Novel H1N1 also lacks genetic markers for virulence identified in the 1918 virus and is expected to remain a mild virus, but this information about transmissibility has unsettling implications.
* A recent laboratory study in which ferrets were coinfected with H5N1 and the seasonal H3N2 virus found that a new reassortant virus with genes from both was produced 9% of the time.
* the most likely scenario and also the consensus view at the moment is that novel H1N1 will surge in the next influenza season in the northern hemisphere.
* Like the 1918 and 1957 pandemics, it will infect 15-40% of the population.
* If the young are the chief susceptibles and the virus does not increase in virulence, deaths would probably be less than CDC's 1999 projected best case of between 89,000 and 207,000 deaths.
* the current H1N1 wave could cause businesses to anticipate supply chain problems in the next 6-10 months and adjust stockpiles accordingly, which could improve resilience and lessen economic impact, assuming a full-bore pandemic does strike.
* Experience from 1918 to SARS demonstrates that only full and candid disclosure of the truth will contain panic.
This author is wary of the term 'risk communication.'
It implies management of information.
You do not manage the truth.
You tell the truth.
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