Discussion - A Summary of Worldwide Human H5N1 Cases in 2011

[sharon sanders]

Re: Discussion - A Summary of Worldwide Human H5N1 Cases in 2011

comments from above blog:

Helen Branswell

Hi. I'd like to discuss this with you.
I don't know why you said Donald McNeil said incorrect when he said H5 has been "known" to have infected only about 600 people. That information is correct. It's also true that we shouldn't assume we've seen every case, as you point out. But the way McNeil worded the sentence covers that. He's not saying: H5N1 has only infected 600 people ever. He's saying: Only about 600 cases have come to light. Which is correct.You argue that H5 cases that have been diagnosed are probably a proportion of the denominator, not the full denominator. Everyone hopes that hunch is correct. But there have been a lot of small serology studies looking for undetected cases. They've been done in several countries. You cite one which found a very high 9 per cent seropositive rate. I hear that some in the flu world have concerns about the cutoff levels that group uses. But even if their finding is correct, many serosurveys have found no seropositives. Those that have found some evidence of conversion have seen it in <4% of people tested. You can find a list of ~18 studies that have been done in this document for a meeting of the WHO's Strategic Advisory Group of Experts on immunization in 2009. See page 20.http://www.who.int/immunization/sage/... Apparently there have been a few studies published since that are not included on this list but they don't change the general finding -- few asymptomatic cases are found.I am sure there are cases that are undetected and unreported. I'm sure that means both the numerator and the denominator are off. But is there evidence that the denominator may in fact be much larger than it currently appears, maybe as large as 9 % of the population of Asia? Seems like a stretch.

Cheers.

Helen Branswell
medical reporter
The Canadian Press
Like Reply
30 minutes ago F

profvrr, Virus guru, Professor of Microbiology, TWiV.tv host
McNeil was being misleading (maybe not deliberately - he did respond on this). Most of the readers would come away from his statement thinking that H5N1 has a 50% CFR. He should explain the caveats. I don't mean to single him out; most other writers bluntly state the CFR is 50%. We don't have the data to make that conclusion. The studies you cite aren't adequate to provide a denominator for the CFR. They were either done too long ago or in the wrong populations (e.g. not rural farmers where one would expect virus circulation). Even one percent of rural Asian population would be millions and that would significantly change the CFR. No one is adequately questioning the H5N1 CFR and that has lead us to the NSABB situation which is dreadful. It's not a stretch.
Like Reply
20 minutes ago in reply to Helen Branswell

josh powell
We should not fear the publication or methodology in regards to creating more virulent lab-based H5N1 or other influenza strains. What we should fear is the increased and easy access to technology considered to be advanced 10 years ago. One can order "kits" by mail that allow for easy cloning. One can order various cell lines that are easily expanded in tissue culture. Finally one can order custom-made oligos of 100 nucleotides or even entire custom plasmids of multiple kilobases from a variety of online companies. Stringent monitoring of where and who is using these kits, cell-lines and sequences is essential.

10-kb (sometimes less) is all that is needed to produce a very nasty and virulent virus. I do not worry about that scientist in a university or national lab "accidentally" releasing a lethal virus unknowingly in a way Hollywood likes to portray. I worry about the online availability of ordering this information and with a simple PCR machine someone could create a new virulent and lethal strain. Cloning in the last few years is now akin to homebrewing your own beer, this is very scary in the wrong hands.

Josh Powell
Oregon State University
Ph.D student

Like Reply
55 minutes ago

profvrr, Virus guru, Professor of Microbiology, TWiV.tv host
Nasty in lab is not necessarily nasty in people. The point is even good scientists don't know how to make a pathogen, even with techniques what they are today.

 

[sharon sanders]

Re: Discussion - A Summary of Worldwide Human H5N1 Cases in 2011

This is excellent.

Was it send to ProMEDmail ?

And they published it on a China H5N1 update page along with more of our threads (bolding mine):

Readers' attention is draw to an 'Original Paper' newly compiled by
FluTrackers.com, entitled: "A Summary of Worldwide Human H5N1 Cases in
2011", that is fully sourced including charts, graphs, and maps, all
or part of which may be freely reproduced (see
http://www.flutrackers.com/forum/showthread.php?t=179069).

The Abstract reads: "In 2011, 59 human cases of H5N1 were reported
from around the world, a 23 percent increase over 2010. 5 countries
reported cases in 2011, Bangladesh, Cambodia, China, Egypt, and
Indonesia. Almost half of the 59 cases (about 45 percent) were
children under 10 years old. The fatality rate did not appreciably
decline in 2011, about half of all the reported cases died. 4 small
family clusters were noted during the year. The source of exposure for
all of the cluster cases has been reported as exposure to sick and
dying poultry. None of these clusters resulted in sustained
human-to-human transmission. Based on an analysis of the 2011 data,
the potential for a virulent H5N1 pandemic has not diminished."

The document begins: "The big H5N1 news of 2011 was the bioethical
debate surrounding the publication of the details of genetic research
by 2 groups of scientists who were able to create a laboratory strain
of H5N1 that maintained its virulence and was easily transmissible
[among ferrets] in aerosolized droplets. A few of the many media
reports and commentaries are referenced in this FluTrackers report
[http://www.flutrackers.com/forum/showthread.php?t=177126]. Equally
as important, but without the accompanying media hype, is that there
was a 23 percent increase in the number of worldwide H5N1 human cases
over the number of cases in 2010. In 2011, at least 59 cases were
recorded; in 2010 the total was only 48. The following summary of
human cases from 2011 is generally organized according to the outlined
presented last year in "A Summary of Human H5N1 Cases in 2010"
(http://www.flutrackers.com/forum/showthread.php?t=157504).

Perhaps of greatest interest is the section on High H5N1 Infection
Rates Among Small Children. "Since 2009, there has been an observable
trend of an increasing number of H5N1 infections among very young
children. This should not be surprising since H5N1 is a novel
influenza virus, and young children are more susceptible to influenza
viruses in general. What is surprising is the recovery rate (that is,
low CFR) for this age group. As virulent as H5N1 is, many of the
infected children survive. The children survive at a much higher rate
than their infected adult counterparts. These children would not have
time to build up cross-protective immunity, so the recovery process
for these young people is worthy of further study. Also, most of these
child infections do not occur in family clusters so questions arise
about the exposure source for these children. What is the nature of
contact between exposed poultry and these young children? Is there a
mild asymptomatic strain of H5N1 circulating in some countries?" But
perhaps there is greater resort to treatment with neuraminidase
inhibitors in the case of young children?

The original diagrams in this paper provide an elegant and easily
assimilable condensation of the information contained in the text. -
Mod.CP]


Again, thank you Al, and thank you to the entire team!