Vaccinating against bird flu is allowed by the European Commission as of 12 March. But the conditions set by the EU make it impractical.
Which vaccine can be used?
A vaccine may only be used if it has been officially registered. It must not be a live or attenuated live vaccine based on an influenza virus.
In addition, for mandatory monitoring it is necessary that the vaccine can be distinguished from the field virus when testing (blood) samples. There is currently no vaccine available in the EU that meets these conditions.
When will a vaccine be available?
Research into three candidate vaccines by Wageningen Bioveterinary Research is almost complete. This should show that vaccinated animals do not get sick and that they are so well protected that they do not shed any virus if they become infected. Or that they excrete so little virus that there is little or no virus spread.
This should prevent the field virus from spreading unnoticed and vaccination actually increases the risk of spreading. This is followed by a field trial and if all conditions are met, vaccines can be used.
What conditions apply to vaccination?
Because it is necessary to prevent poultry from spreading the field virus of bird flu despite vaccination, strict conditions apply to monitoring. Dead animals on the farm should be examined every week to ensure that they have not contracted any field virus. It is not clear whether a vet carries this out or whether the poultry farmer sends the animals to a laboratory.
In addition, a clinical inspection of the animals is mandatory every four weeks, including the taking of a large sample.
How large is the mandatory sample?
Poultry health specialist Sjaak de Wit of Royal GD assumes a random sample of sixty samples. It is unclear whether these should only be blood samples or also PCR samples from swabs from the trachea and cloaca. It is also not clear whether combining samples is allowed.
Taking the samples and the clinical inspection will require a lot of manpower, it can easily take three hours per company. If 1,000 poultry farms vaccinate, 250 farms must be sampled weekly. That requires about twenty full-time workers. The NVWA is already struggling with staff shortages and poultry veterinarians have no time left.
Are there any other objections?
On a laying hen farm, the current requirement means about twenty visits during the laying period. This increases the risk of bird flu being introduced. Furthermore, the strict monitoring entails a lot of costs, which come on top of the vaccination costs.