Importance of foot and mouth disease vaccine purity in interpreting serological surveys

SMITSAART, E.; ESPINOSA, A.M.; MARADEI, E.D.; COSENTINO, B; GUINZBURG, M; MADDONI, G; CADENNAZZI, G; BOTTINI,R; FILIPPI, J; BERGMANN I.E

REVUE SCIENTIFIQUE ET TECHNIQUE DE L4OFFICE INTERNATIONAL DES EPIZOOTIES

OFFICE INT EPIZOOTIES

Año: 2015 vol. 34 p. 755 - 766

0253-1933

The aim of this study was to determine whether the degree of purity achievedin conventional vaccines against the foot and mouth disease virus in Argentinainterferes with the interpretation of seroepidemiological surveys for confirmingthe absence of viral activity, which are performed to support the recognition offree zones practising vaccination.The evaluation of 168 vaccine series due to be marketed in Argentina (2006?2012)and subjected to official control testing in cattle, as well as repeated vaccinationof cattle and other species using vaccines with high antigen concentrations,demonstrated that they did not induce antibodies to non-structural proteins(NSPs).The results show clearly that vaccines with satisfactory potency do not inducea response to NSPs, even by forcing the immune response through moreconcentrated doses with multiple valences and revaccination protocols atshorter intervals than in vaccination campaigns. These results confirm that thevaccines used in routine vaccination programmes have a degree of antigenpurification consistent with the needs observed on the basis of sampling forserological surveillance. Moreover, serological surveys conducted in 2006?2011by Argentina?s official Veterinary Services ? the National Health and AgrifoodQuality Service (SENASA) ? on more than 23,000 sera per year from cattleincluded in the vaccination programme, in order to confirm the absence of viruscirculation, revealed an average 0.05% of reactive results, consistent with thespecificity of the tests.In conclusion, the vaccines produced by conventional methods and with provenpotency that are available in Argentina are sufficiently purified to ensure that theydo not interfere with the interpretation of sampling for serological surveillanceperformed to support the recognition of FMD-free zones practising vaccination.