vaccine adverse

Vaccines

Health products that trigger protective immune responses and prepare to fight future infections from disease-causing agents.

Benefits

Vaccines can lessen the severity and can prevent infection of future diseases.

Licensing

Vaccines are licensed by the USDA.

APHIS

Animal and Plant Health Inspection Service, a multifaceted agency of the USDA responsible for regulating veterinary biologics like vaccines.

Core Vaccines

Vital vaccines that are important for all pets based on risk of exposure, severity of disease, or transmissibility to humans.

Non-core Vaccines

Vaccines that are administered based on the pet’s specific exposure risk.

Veterinary Biologics

Products such as vaccines that are regulated by APHIS to ensure safety and effectiveness for animal health.

Exposure Risk

The likelihood of a pet coming into contact with specific pathogens, which influences the decision on vaccinations.

Transmissibility

The potential for a disease to be spread from animals to humans, a key factor in determining core vaccines.

Canine Distemper Virus (CDV)

A contagious and potentially fatal viral disease in dogs affecting the respiratory, gastrointestinal, and nervous systems.

Canine Adenovirus-1 (CAV-1)

A virus causing infectious hepatitis in dogs; immunization often involves CAV-2 to protect against CAV-1.

Canine Parvovirus (CPV)

A highly contagious virus causing severe gastrointestinal illness in dogs, especially puppies.

Canine Parainfluenza Virus (CPiV)

A virus that contributes to canine infectious respiratory disease, often included in combination vaccines.

Canine Rabies Virus

A fatal viral disease that affects the brain and spinal cord of mammals, including dogs; vaccination is legally required in many areas.

Canine Influenza Virus (CIV)

A virus that causes respiratory illness in dogs; vaccination is recommended based on risk evaluation.

Leptospira

Bacteria that cause leptospirosis, a disease in dogs that can be prevented by vaccination depending on exposure risk.

Feline Panleukopenia Virus (FPV)

A highly contagious viral disease that affects cats, leading to severe illness and is often included in core vaccinations.

Feline Herpesvirus-1 (FHV-1)

A virus that is a major cause of upper respiratory infections in cats; included in core vaccines.

Feline Calicivirus (FCV)

A virus that causes respiratory infections and oral disease in cats, part of the core vaccination schedule.

Feline Leukemia Virus (FeLV)

A viral infection that affects the immune system of cats; vaccination is generally recommended for cats under 1 year of age.

Feline Rabies Virus

A viral disease affecting the nervous system, recommended for vaccination due to transmission risk to humans.

Feline Infectious Peritonitis (FIP)

A viral disease caused by a mutation of the feline coronavirus; vaccination is not generally recommended.

Bordetella bronchiseptica (Bb)

Bacteria that causes kennel cough in dogs; vaccination is recommended for those frequently in group settings.

Canine Borrelia burgdorferi

Bacteria responsible for Lyme disease in dogs, often transmitted by ticks; vaccination is based on risk exposure.

Canine Parainfluenza Virus (CPIv)

A virus contributing to respiratory disease in dogs; included in non-core vaccines depending on risk assessment.

Leptospira ssp.

Bacteria that cause leptospirosis; vaccination is recommended for dogs based on their exposure risk to environments contaminated with urine from infected animals.

Canine Influenza Virus (CIV)

A flu virus affecting dogs; vaccination is advised based on risk evaluation, particularly for those in crowded conditions.

Chlamydophila felis

Bacteria that can cause conjunctivitis in cats; vaccination is usually recommended for cats in high-risk environments.

Bordetella bronchiseptica (Feline)

Similar to its canine counterpart; vaccination is recommended for cats in multi-cat environments to prevent respiratory infections.

Feline Leukemia Virus (FeLV)

A viral disease that affects the immune system of cats; vaccination is recommended for cats older than 1 year, especially those at risk.

Feline Infectious Peritonitis (FIP)

A viral disease caused by a mutation of the feline coronavirus; not generally recommended for pet cats.

Inactivated Vaccines

Vaccines containing killed whole-cell viruses or bacteria that cannot replicate in the host.

Stability of Inactivated Vaccines

These preparations are highly stable, making them easier to store and transport.

Dosage Schedule for Inactivated Vaccines

Typically requires 2 initial doses administered 2 to 4 weeks apart for effective immunity.

Immunogenicity

Inactivated vaccines are generally less immunogenic and have a shorter duration of immunity compared to attenuated vaccines.

Adjuvants

Substances added to vaccines to enhance the body's immune response to the provided antigens.

Post-vaccinal Reactions

Potential side effects that may occur following vaccination, often mild and transient.

Examples of Inactivated Vaccines

All canine rabies vaccines, whole-cell Leptospirosis vaccines, and some canine influenza vaccines.

Adjuvant

Substance in vaccines that enhances antigen response and stimulates inflammation for better immunity.

Adjuvant Properties

Components from bacteria like Bordetella, Leptospira, or Borrelia that act as antigens and enhance immune response.

Antigen-Adjuvant Relationship

The combined action of antigens and adjuvants in vaccines to elicit a protective immune response.

Stability

Inactivated vaccines are more stable than attenuated vaccines and are prepared as liquid products for direct administration.

Multiple Dose Vials

Contain vaccines such as killed rabies; can be used for programs like a 10 ml shelter immunization.

Contamination Risk

Using multiple dose vials increases the risk of contamination due to repeated needle penetrations.

Shaking Vials

Tank vials of inactivated vaccines should be shaken frequently to ensure homogeneity.

Mixing Vaccines

Do not mix inactivated vaccines with attenuated vaccines in the same syringe unless specified by the manufacturer.

Safety

Inactivated vaccines are often considered the safest type, as the immunizing agent is dead and cannot revert to virulence.

Humoral Immunity

Inactivated vaccines primarily stimulate systemic humoral immunity, producing IgM and IgG antibodies but limited cell-mediated immunity.

Non-infectious Nature

Inactivated vaccines cannot infect or replicate in the host, ensuring safety during vaccination.

Administration Routes

Inactivated vaccines are administered parenterally, typically subcutaneously (SQ) or intramuscularly (IM).

Mucosal Administration

Inactivated vaccines should not be administered directly onto mucosal surfaces, such as intranasally (IN).

Dosage Schedule

For inactivated vaccines (except rabies), two initial doses are required 2-6 weeks apart without MDA to ensure an effective immune response.

Importance of Timing

If more than 6 weeks elapse between doses of inactivated vaccines, it is recommended to repeat the vaccination series.

Dosing Effects

The 1st dose primes the immune system, while the 2nd dose 2-6 weeks later provides the protective immune response.

Time to Full Protection

Full protection from inactivated vaccines may take 2–3 weeks post the last dose.

Maternal Antibodies (MDA)

The age at which puppies and kittens can be effectively immunized is proportional to the amount of antibodies received from their mother.

Impact of High Maternal Antibodies

High levels of maternal antibodies can block the effectiveness of vaccines, preventing the young from developing immunity.

Vaccine Timing

Immunity can only be produced through vaccination when maternal antibodies drop to a sufficiently low level.

Window of Susceptibility

This period spans several days to weeks when maternal antibodies are too low to protect against disease but too high to allow vaccine effectiveness, leaving puppies and kittens at risk.

Predictability

The exact timing of maternal antibody (MDA) fade cannot be predicted, but vaccination should be completed by 16 weeks.

Schedule

Vaccination should occur every 3 (or 2)-4 weeks, starting at 8 weeks until 16 weeks.

Timing

Vaccinate as soon as possible after the critical window of susceptibility to ensure an immune response.

Cessation

Stopping vaccinations before 16 weeks may prevent the puppy from mounting its own immune response.

Delay

Starting vaccinations later than 8 weeks can lead to an extended period of susceptibility.

Response

Adult dogs vaccinated within the last year show a rapid antibody response (hours to days) after one dose of an inactivated vaccine, providing protection.

Duration

Inactivated vaccines typically have a shorter duration of immunity compared to attenuated vaccines, requiring annual revaccination (boosters).

Immunologic Memory

If more than 12 months pass since the last vaccination, a single dose may not prompt a protective immune response due to loss of immunologic memory.

Dosing

To immunize beyond 12 months, two doses of the vaccine, spaced 2-6 weeks apart, may be necessary.

Rabies Immunogenicity

The rabies vaccine antigen is highly immunogenic, making it effective in generating an immune response.

Initial Dose

In the US and Canada, a single dose of rabies vaccine administered at ≥12 weeks of age is considered sufficient to induce protective immunity.

Onset of Immunity

The legally defined onset of immunity from the first dose of rabies vaccine varies according to state, local, or provincial regulations.

Booster Requirement

A booster vaccination for rabies is required one year after the initial dose, with subsequent vaccinations every three years.

3-Year Vaccine

Rabies vaccination should use a vaccine approved for 3-year administration for booster doses after the first year.

Types

Attenuated vaccines can be live, modified-live (virus), or avirulent-live (bacteria), commonly produced through repeated passage in cell culture.

Immune Response

They induce an immune response that mimics natural infection without causing the disease itself, engaging both humoral and cell-mediated immunity.

Immunogenicity

Highly immunogenic, attenuated vaccines can produce a sustained protective immune response from a single dose, especially when there is no maternal-derived antibody (MDA).

Safety

Attenuated vaccines are considered very safe for use in vaccinated animals.

Mucosal Administration

All vaccines approved for oral or intranasal use are attenuated; inactivated (killed) vaccines will not effect immunization when administered onto mucosal surfaces.

Examples

Common examples include most canine distemper virus vaccines, as well as all canine parvovirus and adenovirus-2 vaccines.

Thermal Stability

Attenuated vaccines, having live antigens, lack thermostability and must be stored and handled with strict temperature control.

Storage

These vaccines are prepared and shipped in lyophilized (freeze-dried) form to enhance stability during transportation.

Post-Dilution Stability

Once the diluent is added to the lyophilized product, the vaccine antigens become unstable and may lose efficacy over time.

Administration Time

It is recommended that reconstituted attenuated vaccines be administered within one hour; those not used within this timeframe should be discarded.

Multiple Dose Vials

Attenuated vaccines are not available in multiple dose vials to prevent instability and ensure efficacy.

Administration Routes

Attenuated vaccines can be administered intranasally (IN) for vaccines like Bordetella (Bb) and Canine Parainfluenza Virus (CPiV), or parenterally (subcutaneously or intramuscularly).

Administration Restrictions

Vaccines intended for intranasal (IN) administration must never be given by parenteral routes to ensure efficacy and safety.

Oral Administration

Attenuated vaccines intended for intranasal use are quickly inactivated when administered orally, making them ineffective for immunization.

Immunization Effect

One dose of an attenuated vaccine can prime, immunize, and boost the immune response, provided that maternal-derived antibodies (MDA) do not interfere with the vaccine antigens.

Puppy Vaccination Schedule

Puppies should receive doses of attenuated (MLV) vaccines, such as CDV+CPV-2+CAV-2, every 3-4 weeks between 8 and 16 weeks of age.

Minimum Age for Initial Dose

The minimum age for the first dose of an attenuated vaccine is 6 weeks.

Final Dose Timing

The final dose at 14-16 weeks of age ensures that the puppy receives at least one dose of the vaccine when maternal-derived antibodies (MDA) are insufficient to prevent active vaccine-induced immunity.

Age-Related Immunological Competence

Administration of attenuated vaccines to dogs younger than 6 weeks of age is not recommended, even in the absence of maternal-derived antibodies (MDA), due to age-related immunological incompetence.

onset

The onset of immunity after a single dose of an attenuated core vaccine is approximately 4 ± 3 days in the absence of maternal-derived antibodies (MDA)

Variability

There is variability in the onset of protection among different vaccines: CDV offers protection in 1-2 days, CPV-2 in about 3 days, and CAV-2 in 5-7 days.

Non-Responders

A small percentage of dogs are genetically unable to develop an immune response, referred to as 'non-responders': Modified Live Parvo (1 in 1000), Distemper (1 in 5000), and no non-responders for Adenovirus; data for cats is unknown.

Responsiveness

'Non-responders' are dogs genetically unable to develop an immune response to certain vaccines.

Parvo

For Modified Live Parvo, approximately 1 in 1000 dogs are non-responders.

Distemper

For Distemper, approximately 1 in 5000 dogs are non-responders.

Adenovirus

There are no recorded non-responders for the Adenovirus vaccine.

Cats

The frequency of non-responders among cats is currently unknown.