Avian influenza is spiralling out of control. Is vaccination the only hope?
At the EPIC conference last November, Professor Ian Brown, head of virology at the Animal & Plant Health Agency did not pull his punches when talking about the past year’s avian influenza catastrophe. “No part of the country is not affected,” he said. “This is a truly GB problem. The scale of the virus is a huge challenge.”
Since October 2021, 270 individual premises have had confirmed outbreaks, all requiring culls. In October alone, 3.2 million birds were either culled or dead of the virus in England. “The impact is huge,” said Brown. Across Europe, an astonishing 50 million farmed birds have now been culled over the past year, according to the latest report into the epidemic by the European Food Safety Authority (EFSA).
The distress is palpable for those who have been affected. Turkey producer Paul Kelly has lost flocks this year, as have other seasonal producers, with over 500,000 free range turkeys dead through infection or culling. Kelly said many farmers who supply this market will be reluctant to risk losing a flock next year and incurring huge financial losses. He is now at the point where he believes vaccination – despite the huge costs and potential problems with international trade – is now the only ‘credible’ way forward to ensure the future of seasonal Christmas poultry.
There are major drawbacks to vaccination. At EPIC, Brown set the scene. Currently it is prohibited but this is under review in the EU right now. It was certainly not a straightforward solution, he said, with the cost alone a big hurdle.
For the vaccine, vaccination, veterinary costs, surveillance, the cost would approach £2,500 per week per farm. In addition, moving vaccinated birds would require PCR testing, at a cost of £2,500 per flock, he said. “Could vaccination work?” he asked. “Only in conjunction with other measures. Other countries have tried it and the disease has continued to spread. While we have some new vaccines and exciting tech, there is no vaccine that meets all the requirements.”
But some producers – including Kelly – are pinning their hopes on fast-moving technology to deliver a workable vaccine programme. It was clear, he said, the current strategy was not working. Kelly also has a hatchery supplying day-old turkey poults to more than one third of seasonal turkey farmers.
“We have been battling AI for over 20 years and the policy of trying to stamp out the disease has not worked. Most countries are now discussing vaccination as the only credible way forward. We have lost the war.
“I liken the situation to the zero tolerance policy for covid in China. They are fighting a force of nature that most experts think they cannot win, and it seems their government has now at last realised that locking down the population to eliminate the disease does not work. We have the added disadvantage that we cannot lock down wild birds that are the primary source of infection.”
“We need to get vaccine approval fast tracked – just as we did with the covid vaccines,” said Kelly. “The vaccine programme need only be for highly susceptible poultry such as turkeys, ducks and geese, or used in geographical areas deemed as high risk. “Secondly, monitoring these vaccinated flocks could be carried out by private veterinary practices to test and check that flocks are not carrying a field strain of the virus. The Animal and Plant Health Agency (APHA) would not therefore need any extra resource.”
Kelly also said it was important to introduce a proper financial compensation scheme: “Christmas poultry producers will have to make some big decision at the beginning of 2023. In the absence of being able to vaccinate and also a compensation scheme fit for purpose, will they risk growing turkeys in 2023?
“Many small independent producers have been wiped out and the larger companies that have had infected premises will have had big losses.”
There have been some developments in recent months to push vaccination up the agenda. On 24 November a conference was held in Paris. The conference – held by the International Alliance for Biological Standardisation – with the topic ‘High Pathogenicity Avian Influenza Vaccination Strategies to Prevent and Control HPAI: Removing Unnecessary Barriers for Usage’ was held to discuss the current situation.
According to the British Egg Industry Council, which sent delegates to the conference, vaccination against AI has been a subject of significant discussion within the poultry industry. The current strain of H5N1 appears to have spread globally and there is increasing interest in AI vaccination both in the UK and also among a number of trading partners.
At the conference, it was decided that there are four key points to be addressed before vaccination could go ahead:
• Need for effective vaccines (preferably more than one to ensure competition) • The vaccine has to be easily administered
• There needs to be a cost effective surveillance system in place
• There must be no trade barriers
Ian Lowery, BEIC consultant veterinarian and Mark Williams, chief executive of the BEIC attended the conference. The two summarised the conclusions of the conference in a newsletter to BEIC members, noting that despite a number of potentially suitable vaccines being available commercially, poultry keepers are currently not permitted to vaccinate in the UK.
Vaccination is also prohibited in the EU. The BEIC is generally supportive of the pursuit of a vaccine. There are a number of vaccine trials which are either in discussion, or underway. Vaccines against bird flu made by three different pharmaceutical companies against the current H5 viruses are being tested in laying hens at Wageningen Bioveterinary Research (WBVR).
Williams and Lowery said in the event that vaccination against AI is permitted, then a number of elements need to be considered. Trade is a major consideration. Export of poultry products, day-old chicks, hatching eggs, poultry meat and table eggs would be severely impacted if any commercial poultry in the UK were vaccinated as the certificates which allow for export of these goods stipulate that the UK does not have endemic HPAI and does not vaccinate against it, Lowery and Williams noted.
“Whilst these certificates can be re-negotiated, the process is slow and there is no guarantee that our trading partners would accept goods from countries which vaccinated,” they said in their note to BEIC members. “The concern for them would be that through vaccination we ‘hide’ the incidence of disease in commercial flocks and do not really know what our country status is in relation to HPAI.” As more countries AI vaccinate, concerns of this nature reduce and trust in surveillance programmes, which are used to demonstrate the disease status, increase.
Surveillance is also a consideration. Williams notes that where AI vaccination is conducted, flocks which have been vaccinated will need to undergo intensive monitoring to prove that they are not silent carriers of AI.
“There is currently no defined monitoring programme, nor is there lab capacity to conduct such monitoring at this time. However, it is anticipated that some kind of sampling and testing would need to be conducted from every vaccinated flock on a monthly basis,” Williams and Lowery noted.
A further consideration is vaccine selection. Any programme of HPAI vaccination would need to monitor prevailing strains and be able to consider which vaccines would be best suited to offer protection. Different vaccines have different routes of administration and may require different surveillance programmes depending on the circumstance. It is likely to take some time for us to have suitable vaccines available and rolled out to long lived birds in the poultry sector (eg, layers and turkeys etc).
As with other diseases which we vaccinate for, no vaccine can offer 100% protection from disease and there will need to be ongoing attention to high standards of biosecurity whether or not vaccination is permitted over the coming years.