One seminal study of the natural history of Bb indicated that the duration of clinical immunity (reduction of disease) may be as short as ~6 mo. The latter endeavor requires well-designed and well-conducted field trials, including disease reporting however, these types of studies are rare. It is difficult to model heterogeneous household conditions comprising the plethora of the host, environmental and pathogen cofactors that can contribute to the brevity or longevity of protective clinical immunity. However, the validity of using such studies employing group-housed, genetically similar subjects to determine DOI conferred by vaccines to household dogs is questionable. 74,91,92 Such studies, usually conducted at peak immune response after vaccination, can generally accurately assess the ability of a vaccine to reduce disease. 90ĭuration of immunity and related recommendations for annual vaccination for Bb and CPIV are largely based on experimental infections in seronegative laboratory beagle puppies. 85,86 If an IN (modified-live) Bb vaccine is inadvertently administered by injection, the vaccine package insert or manufacturer should be consulted, as resulting inflammatory reactions can be serious. Exceptions include dogs that cannot be vaccinated IN, or in the case where the injectable Bb vaccine is used simultaneously with the injectable core vaccines as a booster for IN primed responses in a puppy series. Therefore, the use of single-component oral and injectable Bb vaccines is not recommended. 88,89 Only the current combination IN and injectable (core) vaccines contain these pathogens. 87 There are no similar published studies concerning the use of the single-component oral vaccine for this purpose or any use in household dogs.ĭogs that are at risk for Bb are also at risk for canine parainfluenza virus (CPIV) and canine adenovirus virus-2 (CAV-2) and should be vaccinated for all three pathogens. 86 However, this strategy has not yet been evaluated with current canine vaccines for Bb or other pathogens.Ĭoncerning boosting of Bb vaccines, current combination IN and single-component acellular injectable Bb vaccines have been shown to induce equivalent anamnestic (memory) Bb-specific IgG and IgA responses when used as booster vaccines in previously immunized adult household dogs. 85 One study using a combination of IN and injectable (whole-cell bacterin) Bb vaccines demonstrated a significant clinical benefit to this approach versus either vaccine alone. Currently, heterologous prime-boost is being widely investigated in an effort to improve responses to vaccines for COVID-19. 83 Although little studied in small animal veterinary medicine, there is an extensive comparative literature, 78 including a dog-relevant Bordetella pertussis murine model, 84 supporting this approach. This strategy is called “heterologous prime-boost” and involves administering different forms of an antigen by different routes to broaden and extend a response. There may be an immunological benefit in combining different vaccines and routes of administration in a primary series. This is because it has been recognized that the common mucosal immune system, as originally conceptualized, was an oversimplification and that there is compartmentalization of mucosal immune responses, at least to some extent, making IN delivery of antigen more effective than oral at stimulating responses in the respiratory tract. 74–76 However, in general, the IN (versus oral) route of administration is preferable for respiratory pathogens. 76 Altogether, available data indicate that commercial vaccines for Bb all “work” at some level, regardless of the route of administration. 75,76 Data from these studies 75,76 are conflicting concerning the equivalency of the oral versus IN route in conferring immunity one showed no difference between routes, 75 whereas the other demonstrated superior clinical efficacy of the IN route. More recently, current combination IN and single-component oral vaccines for Bb have been directly compared. Previously evaluated 74 challenge of immunity studies in Bordetella bronchiseptica ( Bb)-seronegative beagle puppies have provided variably convincing evidence of the efficacy of inactivated injectable, modified-live combination IN and single-component oral vaccines for Bb.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |