Duration of immunity induced by companion animal vaccines

Abstract

Concerns about possible adverse effects from annual vaccination have prompted the reanalysis of vaccine protocols for cats and dogs. In the last decade, several veterinary advisory groups have published protocols that recommend extended revaccination intervals for certain 'core' vaccines. In addition, practicing veterinarians have been asked to consider vaccination as an individualized medical procedure, based on an analysis of risks and benefits for each vaccine in an individual animal. The calls for extended revaccination intervals prompted considerable debate in USA and internationally. Areas of concern include the amount of evidence to support prolonged immunity from various vaccines, the risk of poor responses in individual animals and the possible effects on population immunity. This review examines how the duration of immunity (DOI) to a vaccine is established in animals and humans. It reviews factors that can affect the DOI in an individual animal, including the types of immune defenses stimulated by the pathogen, and the vaccine, host factors such as age and the level of exposure to the pathogen. In addition, it examines DOI studies that were published for canine and feline core vaccines.

Three-year duration of immunity for feline herpesvirus and calicivirus evaluated in a controlled vaccination-challenge laboratory trial

“…5 One week after the FHV challenge, resurgence and/or new oral ulcerations typical of FCV 6 infection were observed in 7 out 10 control cats and in 3 out of 13 vaccinated cats (they were not 7 included in the FHV clinical score). The frequency of cats with ulcers was significantly lower in 8 the vaccinated group than in the control (23% in vaccinated group versus 70% in control group, 9 Fisher's exact test, p=0.04). When the average FHV clinical scores of the cats that displayed 10 FCV-induced ulcers were compared to the average scores of those that did not, no significant 11 difference could be found.…”

“…FCV 7 infection is associated with oral ulcerations and occasionally with severe systemic disease. Along 8 with feline parvovirus (FPV), FHV and FCV are considered core vaccine components that all cats 9 should receive. 10 In the last decade, annual revaccination of pets has been challenged, especially in cats, where 11 injection-site sarcomas raised the question of the benefit/risk of annual revaccination.…”

“…All cats were periodically tested for FCV and FHV antibodies during the immunization phase. 8 Blood samples were collected from the jugular vein on dry tubes on Day 0, 28, 56, 84, 175, 266, 9 357, 392, 420 and then at 3 month intervals until challenge. Blood was also collected after 10 challenge.…”

“…On Day 1534, each cat was inoculated with 10 5.5 CCID 50 of 8 FHV C27 strain by oculo-nasal route under general anesthesia. 9 Cats were monitored according to the general principles of European pharmacopoeia monographs 10 No. 1206 and 1101 respectively:…”

Purification of the Specific Antibody of Foot-and-Mouth Disease Virus Serotype A by Ion Exchange Chromatography

“…FMD has severe implications for animal farming. Since FMD is highly infectious, it can be spread by polluted animals by aerosols, contact with contaminated farming equipment, vehicles, clothing, or feed, and through domestic and wild predators (3).…”