What does a proper vaccination program look like?

What does a proper vaccination program look like?

FURTHER INVESTIGATIONS HAVE HIGHLIGHTED THE FACTS THAT:

  • In endemic countries, day old chicks are carrying high levels of maternally derived antibodies that are interfering with live as well as killed ND vaccines applied at the hatchery, up to a point where neutralization is complete and prevents any vaccine take.
  • Vaccinating in the farm has many drawbacks and remains unreliable: lack of education of the workers, too much time required to apply the vaccine, drinking water quality and residues of sanitizer in the water makes farm vaccination a very unreliable process.
  • Live attenuated vaccines that are the backbone of a broiler ND vaccination program are responsible for lesions of the upper respiratory tract, post vaccination and rolling reactions that slow down the growth and leave the chickens susceptible to other pathogens.

These limitations explain why it is really not uncommon to discover unprotected flocks in endemic countries and why severe clinical outbreaks are often reported, despite “good vaccination” practices.

So far, the general opinion in the poultry industry was that ND would stay for long in most ND endemic countries and that is why vaccination was, at best, considered as an aid to maintain poultry production, but definitely far from being an effective tool of an eradication program.

On the other hand, in low challenge countries, the uncontrolled circulation of lentogenic (vaccine) strain was regarded as an issue, since it was frequently responsible for bacterial opportunistic secondary infections leading to extra antibiotic use and to higher condemnation rates due to airsacculitis.

This was the situation when Ceva launched Vectormune® ND in 2013.