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Summary: "As one hopes to induce so called 'herd immunity', any flock or herd which has been vaccinated will still achieve lower excretion levels into the environment and also will have only mild clinical disease - which most us thought was the object of the exercise. The myth of the silent spread of virus by vaccinated birds flying over DEFRA offices is just that. - utter nonsense...."

From Dr Fink's email to warmwell, February 2007

Mary, As I am sure that you know, this is complete rubbish and shows that all the 'Virologists' invented by Fred Landeg in Page Street, in answer to a question from the Countess of Mar are a myth. 
DEFRA cannot...even advise their representatives properly and know nothing of how vaccines work.

Vaccines are used ( in man or animals ) for two purposes:

1   To protect a population against a ' wildtype' infection
2   To preserve individuals within a population

All vaccinees will take a finite time to raise antibody and a white cell response to a vaccine.  When they have, if they meet a 'wild type' organsim after appropriate vaccine, they  may become infected and replicate some virus within them. They will be protected against clinical disease  ( protecting the individual) and they themselves will be a very low infection risk ( or none at all- there are no absolutes in biological matters) will NOT spread 'wildtype' virus in to the environment. 

The obsessional focus by DEFRA is on the period after vaccination and theoretically before a complete response has been made by the vaccinees. In fact any individual ( man or beast or bird) who has partially responded and then meets ' wildtype' virus early after vaccine may have mild clinical disease and may  excrete some virus in to the surroundings. That does not matter because the whole exercise is to reduce the spread of 'wildtype' and this will be a partial result in these few cases with much reduced virus shedding.  As one hopes to induce so called ' herd immunity' any flock or herd  which has been vaccinated ( but perhaps a bit late !! back to indecision in DEFRA) will still achieve lower excretion levels in to the environment and also will have only mild clinical diseae - which most us thought was the object of the exercise.   

The myth of the silent spread of virus by vaccinated birds flying over DEFRA offices is just that.  - utter nonsense....


----- Original Message ----- From: Dr Colin G Fink To:mary critchleySent: Wednesday, February 14, 2007
I have added some clarification for the readers:

Half truths do seem to persist. There are undoubtely logistical difficulties to vaccination in poultry. I think that there is some comfort in the fact that all the outbreaks have been in domestic rather than wild birds. So it is within our power to control these outbreaks if sensible policies are enforced. It is an especial risk in a confined high density flock as we have seen. ( Bit tough on these birds though, that have no real life anyway. But that is a part of the problem- intensive factory methods to produce cheap meat. I do not like that for several reasons, not all virological.)

High density of birds  increases the transmission rate of the infection between individuals. If they were all vaccinated , any virus infection introduced would have low flock spread with little if any subsequent shedding into the environment.. The birds would remain clinically well. However no symptoms in the birds together with no understanding by the handlers of even small risk of infection spread outside a flock could lead to some transfer of organisms out of the flock if the biosecurity was not strictly observed. No biological system is ever absolute especially when run by staff who do not understand transfer of infection .

I am not sure what is better for these hapless creatures and their factory bosses in high density rearing. Such a devastating outbreak with much virus shedding as we saw followed by immediate culling or no virus shedding but a minimal risk of ' wild type' viral carriage for short while only?

I am sure that vaccine would break the transmission cycle even in high density flocks. Vaccine for all the smallholders' birds would be very effective in preserving them clinically well and in lower density flocks transfer of wild type virus would be minimal or none. It is theoretically possible to have a small replication of virus in any succesfully vaccinated individual after vaccination. But we do not look because the criterion for successful vaccination is maintenance of good health of the individual and also the failure of 'wildtype' to gain a foothold. What we are concerned about is whether any individual can then act as a vector for the disease. That is very unlikely in a vaccinated flock. Which is the 2nd reason for vaccination .

The Vet lab virologists are producing fine data on the sequences of the viruses and the politicians seem conveniently deaf to the meaning of this.

I believe that the carcase material brought in was infected with H5N1. One way of transfer of this infection so rapidly to the flocks would be If  the residue of the carcase meat has been ground up and fed to the new chicks as a high protein feed. That is one way the infection could be transferred into the turkey chick stock. I expect that if they wish to do this they will boil it now.

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Email from Dr Ruth Watkins Feb 16 2007

Dear Mary

The international trade legal, illegal, legal but poorly monitored, legal but cheating on the paperwork etc is just brilliant for spreading agents which are highly infectious round the world (if not attendant mosquitoes, midges, fleas and ticks etc.). It can happen innocently and unintentionally. Only a tiny amount, even one infectious particle or virion, can be sufficient to infect a susceptible host such as a fowl with HPAI H5N1.

I expect sheep 'breeds' were brought into the UK by the successive incomers from neolithic farming onwards with their attendant diseases. In the realm of human infectious disease as you know infection is taken along with the moving humans. In the case of humans we cannot prevent fairly free movement except in special circumstances because of disease e.g.SARS and of course we don't aim to cull every infected human. Bacteria as well as viruses are carried around the world. The latest strain of Clostridium difficile was brought over from Canada it seems - this is a new strain with a tenfold increase in toxin production. Now it is here in our hospitals too.

I can't see any reason for there being all this world trade in live and raw dead animals and their products. Perhaps cooked meat products. Perhaps occasional introduction of breeds to improve nutrition in other countries but with extra care and quarantine. Semen should be something that can be subject to thorough verification, quarantine and testing - i.e. being held in liquid nitrogen for 6 months while all is checked out.

This would be very hard on New Zealand that depends on export more than any other country I can think of - and has been accused of very little. Perhaps the review will have to be selective; address the spread of H5N1 by poultry, address the spread of PMWS etc. the export on cold ships of hung lamb carcasses and beef carcasses might be exempt. I am out of my depth on the territory of trade. However, I would have thought we cannot allow H5N1 and PMWS to spread unchecked.

Politics and farming interests interfere with virology sleuthing. I do commend Ian Brown ( chief avian virologist at VLA) for sticking to his guns over the recent H5N1.

best wishes


Email received from Dr Ruth Watkins, Feb 19 2007

Dear Mary

There is a great reluctance on the part of British intensive poultry farmers to contemplate vaccinating millions of birds. There is a reluctance to vaccinate in the UK on any count - and of course a history of persons vilifying vaccines. I hear that in Holland supermarkets have been unwilling to market eggs from vaccinated birds - so that must be one of the reasons vaccination has not been taken up by many free range producers. I suspect the supermarkets will make mayhem here as well.

Vaccination does not change the actual virus from a hare to a tortoise but the virus shed, if any, from an infected vaccinated animal would have all the properties of the wild virus (e.g. in the case of the highly pathogenic H5N1 it is highly infectious to non-immune poultry, (possibly excepting ducks who, although they may become infected, may not become ill and die as a result of infection), and just as lethal as before with the same short incubation period and swiftly progressing mortal illness). Hence the EU proposal to place unvaccinated (non-immune) sentinel poultry in a vaccinated flock as these would pick up any infection in the flock and fall ill and die.

The question about avian influenza vaccination virus preparations is: Are they protective against the current strain of H5N1? That is, do the vaccines raise protective immunity to the 2007 H5N1 Qinghai related strain currently in Europe? As the Haemagglutinin of viruses can be sequenced within days, the changes in the antigenicity of the H5 molecule of the H5N1 virus can be monitored. It can also be checked out in the laboratory by neutralisation assays.

I would have thought there is now good scientific evidence on the efficacy of H5 vaccines available to the EU with regard to current strains of the H5N1 virus.

Also, once poultry have had a full vaccination course, it is known when they have the full protection offered by the vaccine. I believe this is about 3 weeks after the first injection in a course of two (when inactivated, dead, virus vaccine). There should be information from Vietnam about vaccine efficacy in the field as well.

Where has the idea that there is long term circulation of H5N1 in a fully vaccinated flock in the absence of disease in the flock come from? What is the documentary evidence for it? I would have thought that if the virus were to continue to circulate in a fully vaccinated flock there would be the evidence of diseased birds as the immune cross reactivity of the vaccine virus would be so poor as to have failed to evoke the protective antibody, neutralising antibody to H5.

In fact in Vietnam they have had a long period of freedom from human cases of H5N1during their vaccination programme, presumably because the virus was not circulating in their domestic poultry. I have not read of their monitoring of H5N1 in the poultry during this period.

(Breakdown in vaccine protection in Vietnam can occur in various ways. They face two main difficulties. First to keep up the protection by vaccination, particularly of chicks and young birds coming into the vaccinated flocks. Secondly there is the continuous threat of a breach of border security by the poultry smugglers from China who can introduce H5N1 strains circulating in Southern China into Vietnam by bringing in unvaccinated as well as infected birds. This is different from the spread by wild infected birds that could also occur, from South CHina into Vietnam. This latter situation is exactly what the vaccination programme of the flocks in Vietnam is designed to protect against.

I would like to know the reason for the recent outbreaks they have had in one or two regions of Vietnam. How have fully vaccinated flocks fared in those regions? How does the virus isolated match up with the vaccine virus? I have looked at the ProMed reports on the recurrence of H5N1 in late 2006 and 2007 in Vietnam

There are a series of short reports on Promed and I feel that what I can glean from them is summarized above. This supports my assertions I feel. They have suspected H5N1 infection of humans in several instances but infection has not been confirmed. They have had no deaths since November 2005, and I presume also no further confirmed cases in humans either. That is a tremendous record when you consider Indonesia or Egypt for instance. )



































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