Wednesday, July 15

H1N1/swine flu: Lies, damned lies, and mathematical modeling.

Will wonders never cease? Everyone and his uncle in the press have picked up on the importance of the story that Reuters' Maggie Fox reported on yesterday and the Imperial College study she mentioned. See my July 14 post, How widespread is swine flu? Without accurate numbers, who knows?.

Welcome to the data-discussion party, ladies and gentlemen of the press; it's only been roaring along since May.

BBC News:
Better data needed on swine flu

Agence France-Presse:
Data gaps could give distorted picture of swine flu: study

The (U.K.) Times Online's editorial staff decided not to beat around the bush:

Scientists call for more accurate measure of swine flu death rate

There you go; that's coming right out and saying it in plain English.
More accurate ways of measuring mortality from swine flu are needed to help health officials to make the right decisions about managing the pandemic, scientists said yesterday.

Standard methods of calculating death and hospital admission rates for the influenza A (H1N1) virus are unreliable and can both underestimate and overestimate the true figures, according to research at Imperial College, London.

One of the key measures of the virulence of any disease is its case fatality rate (CFR), which is generally calculated by dividing the total number of known cases by the total number of deaths. A good estimate of the CFR for swine flu, and of its hospital admission rate, is needed to help healthcare planners to decide on appropriate measures for containing infection, such as school closures, and on vaccination strategies.

Any changes in the mortality rate must also be monitored closely to determine whether the virus is mutating to become more virulent, which may require policy changes.[...]
It's nice to learn that the biomedical and public health communities have decided to explain to the public that there are serious problems with data collection and mathematical modeling on swine flu.

But it was only a matter of time before studies such as the Imperial College one would be in the works. So attempts by governments to hide their poor pandemic planning behind crummy data collection and bad math were bound to be exposed.

And now there's a particular urgency to get better data on swine flu infections:
Surging Swine Flu Pandemic Faces Months Without New Vaccine

A vaccine to contend with the mounting swine flu pandemic is not going to be readily available for months as the death toll from the virus increases, according to a statement made by the world's top health official on Wednesday.

World Health Organization chief Margaret Chan made the comments after Australia and Japan reported a surge in cases of the A(H1N1) virus, and Argentina experienced a sharp increase in the number of deaths from 94 to 137 in just three days.

"There's no vaccine. One should be available soon, in August. But having a vaccine available is not the same as having a vaccine that has proven safe," Chan told Britain's Guardian newspaper.

The swine flu viruses currently being used to develop a vaccine do not contain enough of the ingredient needed for the vaccine, therefore WHO has requested that its laboratory network produce a new set of viruses as soon as possible.

Countering health officials in Britain and elsewhere who claimed the first stocks would start arriving in August, she added "clinical trial data will not be available for another two to three months."
And I am under the impression that it takes about six weeks for a flu vaccination to become fully effective -- to the extent it can be, if it's well matched to the influenza bug.

The unexpected delay with vaccine production is so serious that now WHO seems to be giving the green light for the development of a live-virus vaccine. This statement was reportedly put on their website:
"In view of the anticipated limited vaccine availability at global level and the potential need to protect against "drifted" strains of virus, SAGE recommended that promoting production and use of vaccines such as those that are formulated with oil-in-water adjuvants and live attenuated influenza vaccines was important."
"SAGE" is the acronym for WHO's hilariously named advisory panel on immunization, "Strategic Advisory Group of Experts." OOC -- Oligarchs of Chaos -- might be more descriptive.

All right Pundita; stop picking on WHO. Where was I? And from a Reuters report:
[...] [Dr. Marie-Paule Kieny, WHO director of the Initiative for Vaccine Research] said WHO would also work to get better viruses for companies from which to make vaccines. She said the strains that had been distributed did not grow very well in chicken eggs -- used to make all flu vaccines.

One exception -- AstraZeneca's MedImmune unit makes a live virus vaccine that is squirted up the nose and it is easier to produce, Kieny said.[...]
As to whether a live-virus vaccine would require more testing than a killed-virus one -- you can forward your technical questions to MedImmune, which has picked up $61 million to produce a swine flu spray.

But from my informal survey of one reader who studies these kind of questions: "Yes, the live vaccines give better immunity, if they don't kill you."

The problem is that it's very late in the day for hand-wringing. WHO, CDC, ECDC and the rest of the alphabet soup lost two gambles:

They gambled that the swine flu virus acted pretty much in the same way as the seasonal influenzas. It doesn't. And they gambled that an adequately tested killed-virus vaccine could roll off the assembly line by September at latest. Unlikely, which leaves humanity pinning its hopes on a live vaccine.

From now on, the public health community might want to confine their gambling to the roulette table.

But has anyone considered eating a little humble pie and asking China's Ministry of Health how their vaccine manufacturers are planning to pull off a miracle? They're supposed to have a safe vaccine ready in time for the MOH's target September 14 date to begin China's swine flu immunizations.

Maybe they were overly optimistic about the target date. Maybe they were always going for a live-vaccine spray. But I have no idea what they're doing and neither will you, unless you swallow your pride and ask. Wake up.

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