Vaccines protect patients by providing a level of resistance to a disease beyond their innate immune status. Each aspect of vaccine efficacy and duration of immunity is multi-factorial and often difficult to predict in all cases. Further, no vaccine is completely safe and effective in all situations for all animal patients. The American Veterinary Medical Association (AVMA) believes that a medically based approach to vaccination protocols is an appropriate method to address the preventive health needs in multiple species, breeds and individual patients.

The use of vaccination is essential to the health of veterinary patients as well as the general public. Medical decisions related to vaccines, vaccine administration and development of vaccine protocols are among the most complicated decisions in medical practice. Appropriate decisions concerning individual vaccine selection and vaccination program choices are best made under veterinarian-client-patient relationships, wherein the practitioner and client must determine the best patient care programs for implementation. Veterinarians should create a core vaccine program, intended for use in the majority of animals in their practice area as well as a non-core vaccine program, intended for special circumstances/situations for animals in this same practice area and consider the potential for endemic disease exposure, susceptibility to disease and risk/benefit ratios. Veterinarians with an established veterinarian-client-patient relationship are in the best position to make educated recommendations as to the appropriate core and non-core vaccine programs. Vaccine programs should consider all emigration and immigration of animals within a geographical area and the risk of disease in the clinically relevant environment. Vaccine programs should follow all governmental regulations.

It is recommended to follow label indications/recommendations; however, veterinarians may legally exercise discretionary judgment in some instances if medically justified and when in compliance with all governmental restrictions that may apply. All manufacturers’ information, concerning vaccine handling guidelines, (e.g. for temperature, light, transport, expiration date, withdrawal, and disposal) should be followed to help ensure vaccine efficacy, safety, and shelf life. Specific directions as to the method of diluent and antigen mixing should be strictly adhered to so as to avoid antigen destruction as well as adverse chemical or physical interaction(s). Failure to administer a vaccine in the method deemed appropriate by the manufacturer (e.g. allowable concurrent treatments, method of administration) may result in suboptimal protection and/or adversely alter the established safety profile of the product. All manufacturer cautionary warnings on vaccines should be followed. Veterinarians should recognize that failure to use vaccines according to manufacturer-labeled directions may result in potential liability to the veterinarian in the case of an adverse event.

Protective immunity, in the majority of animals, occurs within 21 days following the initial vaccination. Booster vaccination(s) may be required to ensure immunity for the period designated by the manufacturer. Immunity is dependent on multiple factors, including but not limited to, medical history, vaccine type, method of administration, age, and species being vaccinated. The client is encouraged to rely on their veterinarian’s professional acumen to determine the most reliable interval between vaccination and onset of protection against disease.

Programs targeting prompt immunization of susceptible animals are critical in ensuring patient longevity, optimal health and production management. Veterinarians should recall that animals must be physiologically healthy and immunologically competent to respond to the vaccine. When serological titers are used to help determine the vaccination/protection status of an animal, veterinarians should make sure these data have been clinically correlated to host-animal protection studies for the specific diseases and species being tested. For most common vaccine antigens, the correlation between serological response to vaccination, long-term serostatus, and protection in the host animal has not been adequately established. The lack of these data often precludes practitioner’s ability to make well-informed vaccination decisions based on serostatus alone.

Vaccination and revaccination programs, for preventive health care, should be designed to maintain the health of the animals and public health while minimizing adverse effects. Veterinarians should evaluate the risk/benefit ratio to vaccination before implementation on any individual patient or group of animals. Vaccine protocols must be developed in consideration of patient husbandry, endemic disease, geographical location, patient disease susceptibility and immune status. Other factors in the establishment of vaccine management protocols are the general health of the patient, the vaccine antigen/adjuvant combination, methods of administration and concurrent drug or chemical use.

Though vaccine products are continually improving, scientific understanding of vaccine pharmacology and immunology remains incomplete with respect to the prediction and prevention of any/all potential adverse events. Current adverse event reporting systems need significant improvement in the capture, analysis and reporting of adverse events. All adverse events (including protection failures) should be reported to the manufacturer and the United States Department of Agriculture (USDA) to help ensure the continued safety and efficacy of veterinary vaccines.

In developing a vaccine program there are multiple sources of information available from, but not necessarily limited to species and specialty groups, manufacturers, government agencies and other experts. Additional information may be available through the manufacturers’ package inserts and government agencies, in particular the USDA’s Center for Veterinary Biologics. The AVMA continues to advocate for the increased availability of animal vaccines that are safe, efficacious, scientifically based, and clinically practical, to provide practitioners with a basis for developing vaccination programs that maximize the benefits and minimize the associated risks for the patients under their care.

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