EFSA opinion on avian influenza vaccines in domestic poultry

The AHAW Panel’s opinion focused on the high pathogenic (HP) strains of avian influenza of H5 and H7 subtypes, as specifically requested by the European Commission in its mandate. The opinion was prepared with the support of international experts from several EU and International organizations, namely the ECDC[1], EMEA[2], FAO[3] and OIE[4]. The Panel was asked by the European Commission to provide scientific advice of AI poultry vaccinations in order to provide support in the further developments of an AI vaccination policy. The Panel concluded that bio-security measures, such as animal containment measures and controlling animal and human movements around farms, are the first line of protection against the introduction and spread of AI viruses for domestic poultry.  These measures would also reduce the risk for reintroduction of the disease to wild birds from domestic poultry. Currently, AI control measures are based on eradication or culling of infected flocks but more and more countries are beginning to supplement these measures with vaccination programmes.

According to the Panel, current EU authorized AI vaccines for poultry, such as chickens and ducks, meet quality standards and are safe and effective in vaccination against AI in domestic flocks in Europe. However, the degree of effectiveness of vaccines in other poultry and captive birds is not sufficiently known. In the case of a potential outbreak of AI amongst domestic poultry, vaccination of birds may reduce transmission amongst domestic poultry flocks and prevent culling and any related animal welfare impact. The Panel recommended the implementation of good AI vaccination practices using safe and effective EU authorized vaccines when required by the epidemiological situation but also added that their use should be defined in advance of any potential direct AI threat.

In terms of any potential human health impact of the animal vaccines, the Panel noted that the use of authorized EU vaccines is safe and has no negative effect on poultry products for consumers.  In addition, according to the Panel and ECDC representatives, in case that HP AI H5/H7 would become endemic in EU regions in the future as they are presently in some parts of Asia, vaccination of domestic poultry might also reduce the potential for human and other animal cases.

According to the Panel, in order to be able to differentiate between vaccinated birds and those that are infected by a field virus, the DIVA[5] strategy, combined with the use of sentinel birds in order to detect possible AI transmission after vaccination, must be employed to allow the detection of a possibly circulating field strain. However, more research and (field) validation are required to optimise the DIVA strategy.

• Opinion of the Scientific Panel AHAW related with the vaccination against avian influenza of H5 and H7 subtypes in domestic poultry and captive birds