Pago Pago, AMERICAN SAMOA — Recent advances in veterinary medical science have resulted in an increase in vaccines available for dogs. Improvements are continuously being made in vaccine safety and effectiveness. Veterinarians routinely recommend certain vaccines for all dogs (called core vaccines), while others (called non-core vaccines) are used more selectively according to the dog’s environment and lifestyle.

In all cases, decisions regarding the vaccine types and vaccine schedules that are best for each dog require professional advice.

What is a vaccine?

A vaccine is a preparation of either killed or altered microorganisms (often called germs) that is administered into the body usually by injection. The vaccine stimulates the immune system to identify and be ready to fight off the germs if they are exposed to them in the future, the dog will either not get sick or will have a less severe illness.

Vaccines work to prevent certain diseases, not all disease.

What is maternal immunity?

Newborn animals have not yet had a chance to make their own immunity so they need protection against infections present in their environment immediately after birth. They receive this immunity from their mother, as maternal antibodies. Part of this immunity is transferred across the placenta during pregnancy while the pup is still in the uterus, but most of it is transferred in the first milk or colostrum. This maternal immunity is only temporary and declines steadily over the first few weeks of life, largely gone by twelve weeks. The rate of decline is variable, depending on many factors.  It is generally considered that by 3 months of age the pup has a good ability to produce its own immunity.

Why do puppies need more than one dose of some vaccines?

First, without complicated testing, it is impossible to know when a puppy has lost the passive protection it gets from its mother. An early decline in a puppy's maternal antibody can leave it susceptible to infection at a very young age which is why some puppies are vaccinated as early as 6 weeks of age.

On the other hand, a strong maternal immunity can actually interfere with early vaccination which means vaccinations started at 3 months of age is most useful. 

Vaccine type can determine how many vaccines are administered to puppies.  Particularly with killed vaccines, the first dose is a priming dose, and the second dose boosts the response to a higher, longer-lasting level of immunity.

A series of two or three vaccinations administered 4 weeks apart starting at 8 or 12 weeks of age, is the usual puppy series. This series is meant to cover most of the issues as indicated above.

Why does my dog need to be revaccinated?

In most properly vaccinated dogs, the immunity should last more than one year, and often several years. However, immunity does decline with time and this decline rate varies between individuals. To maintain the best protection against infectious diseases, revaccinations have proven very successful.

As vaccines are improved over time, some do not need to be given as often, depending on individual circumstances. Most dogs with low-risk lifestyles can be vaccinated every three years with the core vaccines and as needed for any non-core vaccines.  In general vaccines protecting against viral disease will provide longer immunity than those protecting against bacterial disease. For example Leptospirosis usually requires an annual booster.

How long does it take a vaccine to produce immunity?

Within a few hours of vaccination, the earliest phases of the immune response are being stimulated. It usually requires 10 to 14 days before a reasonable level of protection is established. Killed vaccines may not provide adequate protection until after the second dose. In young puppies, maternal antibodies may hinder protection until later in the vaccine series. Therefore, it is advisable to keep even a vaccinated puppy away from dogs or puppies of unknown vaccination history until it has finished its vaccination course.

Why is the same amount of vaccine given to a small dog and a large dog?

Vaccination doses are the same for all dogs, regardless of size. When these vaccines are tested, all dogs in the test group receive the same dose of vaccine and have been proven safe for dogs of all sizes at the recommended dosage. There has yet to be evidence presented that small dogs obtain the same immunity from small doses or that  smaller doses of vaccinations are associated with a decreased likelihood of vaccine reactions.

What happens if my dog is sick when vaccinated?

To help prevent this situation a veterinary check-up prior to vaccination (even in some clinics a pre-vaccination blood test). This is another reason to make sure young puppies are dewormed prior to receiving vaccination – a heavy parasite load might be making them sick without it being obvious. It is important that an animal is healthy when vaccinated to ensure the proper development of immunity. Vaccinating a sick animal may make them even more sick and is likely to limit how well the vaccine works. 

Can vaccination make my dog sick?

Some dogs develop mild lethargy or soreness one to two days after vaccination. In the case of killed vaccines containing an adjuvant, lump formation may occur at the vaccination site. If this is painful or persists for more than a few weeks with no decrease in size, consult your veterinarian. A few dogs will develop more severe reactions that are forms of hypersensitivity (allergy). The effects will usually occur within minutes but may be delayed by a few hours. Your dog may salivate, vomit, develop diarrhea, hives, or have difficulty breathing. Should this occur, consult your veterinarian immediately.  In a first Aid situation, keeping anti-histamine (diphenhydramine – commonly found brand name Benadryl) available is helpful. A children’s dose if you see problems as described is safe for your puppy; and an adult human dose is safe for your older dog if you are unable to reach your veterinarian.

Do vaccines provide 100% protection?

Vaccines have been highly successful in protecting the majority of dogs against disease. As a direct result of vaccination, previously common diseases such as distemper are now rare. However, there are situations in which the dog’s immunity may be overcome and a vaccinated dog may still develop disease. In such cases, the disease is generally milder than it would have been had the dog not been vaccinated.

How are vaccines administered to dogs?

Some vaccines are given locally, for example into the nose, but most require injection so that the maximum stimulation of the immune system is achieved. Some vaccines are injected subcutaneously (just under the skin) and others are injected intramuscularly (into the muscle).

Which vaccines are recommended for dogs?

Depending on where you live, some infections may be more or less likely. The range of vaccines available includes rabies, distemper, adenovirus (infectious canine hepatitis), parvovirus, leptospirosis, parainfluenza, coronavirus, Bordetella bronchiseptica, Lyme disease, and canine influenza (for details on these diseases, see individual handouts available on veterinary websites such as AVMA, AAHA and many others - “Rabies in Dogs”, “Distemper in Dogs”, “Infectious Hepatitis (Adenovirus) in Dogs”, “Parvovirus in Dogs”, “Leptospirosis in Dogs”, “Kennel Cough or Tracheobronchitis in Dogs”, “Lyme Disease in Dogs”, and “Canine Influenza – The Dog Flu”).

These vaccines are often available in combinations that can be given in one dose. Combination vaccines are convenient and avoid extra injections for your dog. Your veterinarian will advise you on the appropriate vaccines for your dog based on his relative risks and lifestyle.

The following core vaccines are recommended for all puppies and dogs by the American Animal Hospital Association (AAHA) Canine Vaccine Task Force:

• canine distemper virus
• canine parvovirus
• canine adenovirus-2 (hepatitis)
• rabies virus

The following non-core vaccines are recommended for puppies and dogs in special circumstances, dependent on the exposure risk of an individual dog, by the AAHA Canine Vaccine Task Force:

• Leptospira species
• Borrelia burgdorferi (Lyme disease)
• canine parainfluenza virus
• Bordetella bronchiseptica (kennel cough)
• canine influenza

In American Samoa Leptospirosis moves into core vaccine category due to perceived presence of the disease. Rabies moves into non-core due to the rabies-free status in the country.