This is Page 8 of 8 Pages in the Canine Parvovirus Information Center
	Basic Virology A Preface	Canine Parvovirus: What Is It?	The Virus in the Environment: Disinfection	How Infection Happens
(original graphic by marvistavet.com)	The Physical Illness and It's Treatment	Diagnosis of Canine Parvovirus	Caring for the Recovered Dog	Vaccination Options /Prevention

Vaccination Options / Prevention

(original graphic by marvistavet.com)

It should not be too surprising that the biggest step in parvovirus prevention is vaccination. As discussed in other sections, the virus exists virtually everywhere. It is hardy in the environment and easily carried on the surfaces of inanimate objects. Every dog will be exposed and every puppy will be vulnerable at least for a time. Prevention is about minimizing exposure to the virus until the vaccination series is completed. We will be begin our discussion of prevention with vaccination and how to go about achieving a state of immunity for your puppy.

MATERNAL ANTIBODY: OUR BIGGEST OBSTACLE IN VACCINATION

Vaccine is a solution containing a harmless version of the virus, either live and weakened (attenuated or modified live virus vaccine) or killed (inactivated virus vaccine). This virus is injected into the puppy. If there is still adequate maternal antibody present, the vaccine virus will be destroyed just as if it were a real infection. There will be a period of about a week when there is not enough maternal antibody to protect the puppy but too much to allow a vaccine to work. (This period is called the “window of vulnerability.”) Then after this, vaccine can be effective.

To get around this, we vaccinate puppies in a series, giving a vaccine every 2 to 4 weeks until age 16 weeks. By giving vaccine at intervals we are trying to catch the puppy's immune system after their window of vulnerability has closed. We know that by age 16 weeks, we should be able to get a vaccine to "take" but we still begin at a younger age in an effort to provide immunization as soon as possible.

If the mother has been very well-vaccinated (booster vaccine given at approximately the time of breeding so as to maximize her colostral antibodies), an extra dose at 20 weeks may be a good idea to be sure all the maternal antibodies have waned adequately.

After a puppy is born, maternal antibody levels drop by half approximately every 10 days.

Puppies that were born first or were more aggressive at nursing on the first day, will get more maternal antibody than their littermates.

Mother dogs vaccinated at approximately the time of breeding will have the highest antibody levels to pass on to their puppies.

*** REMEMBER, the more maternal antibody a puppy has, the less likely a vaccine is to work and the longer one must wait for antibody to wane and for vaccination to be effective.

SHOULD LIVE OR KILLED VACCINE BE USED?

Killed vaccine is the least effective at penetrating maternal antibody. It is also associated with more vaccine reactions (since more stabilizing chemicals are used in a killed vaccine). As a general rule, live parvovirus vaccine is absolutely the way to go. Killed vaccine should probably not be relied upon for puppies. In fact, nowadays you would be hard-pressed to find a commercially available killed virus vaccine for parvo.

WHAT IS A HIGH TITER VACCINE?

In the mid-1990’s a new innovation in parvo vaccination was developed: the “high titer” vaccine. The term “high titer” refers to the amount of virus in the dose of vaccine and means that there is a great deal more virus present in a high titer vaccine than in a standard vaccine. Nowadays, any vaccine against parvovirus is going to be "high titer." When the puppy is vaccinated, maternal antibody binds the virus present. The idea with a high titer vaccine is that there will be so much vaccine virus present that the maternal antibodies will be used up trying to bind the vaccine. There will be extra virus left over. This extra virus can then stimulate the puppy’s own immune system. High titer vaccines commonly produce full protection by age 12 weeks (though most experts recommend carrying vaccination out to age 16 weeks to be certain - an especially good idea for breeds predisposed to infection such as the Rottweiler, Doberman pinscher, and American pit bull terrier).

At this point virtually all commercially available live vaccines are of the high titer type.

It should be noted that giving vaccine more frequently than every 2 weeks will cause interference between the two vaccines and neither can be expected to be as effective as they normally would. This includes giving vaccines for different infections. Vaccines should be spaced 2-4 weeks apart.

It is commonly held that puppies need a certain number of vaccines for protection to be achieved (usually either 3 or 4 is the “magic” number). The number of vaccines given has nothing to do with protection. In order for protection to be achieved, vaccine must be given when it can penetrate maternal antibody.

An FAQ area has been included in this web site to answer common vaccination questions. To visit this area, click here.

USE OF THE PARVO MONOCLONAL ANTIBODY AS PREVENTION

A commercially available monoclonal antibody product has become available for intravenous injection. Basically, it amounts to instant anti-parvo antibodies in the puppy's bloodstream, sort of like an instant vaccination. This product was designed for the treatment of active infection with parvo but it turns out to be useful for protecting puppies exposed to the virus who are not sick yet and may be incubating an infection. These puppies do not have time to respond to a conventional vaccine but it appears that the monoclonal antibody product can be used as a preventive in this way. It should be noted that monoclonal antibodies, as with maternal antibodies, will inactivate parvo vaccine. An extra month of vaccination should be scheduled for puppies who have had this type of preventive treatment.

VACCINATING ADULT DOGS

Traditionally, parvovirus vaccine has been administered annually to all dogs. Vaccine against canine parvovirus has been included in the distemper combination vaccine (the “DHLPP”, “6 in one” etc.) There has also been some thought that annual vaccination is not necessary, especially for a disease where adult dogs are considered low risk. Many university teaching hospitals have switched to an every 3 year schedule for adult dogs plus the American Animal Hospital Association recommends that parvo vaccination be given to adult dogs on an every 3 year schedule. There is still controversy regarding this practice and many hospitals continue to use the annual guideline as that is usually as far as formal vaccine challenge testing has gone. Do not be surprised if your veterinarian has chosen to follow the university and begin recommending a 3 year vaccination protocol for this virus. To read the AAHA vaccination guidelines: www.aaha.org/resources/2022-aaha-canine-vaccination-guidelines/

(Photocredit: Morguefile.com)

WHAT IS THE MEANING OF A VACCINE TITER?

There is a great deal of controversy regarding whether or not a certain level of antibody can be considered tantamount to protection. Many veterinarians do not feel it is useful to run titers until this issue is resolved (i.e. there is more to protection than an antibody level; there is an entire immune system involved and there is no simple way to assess the entire immune system). Other veterinarians find it cost ineffective to recommend titers prior to vaccination (it costs a great deal more to run the titer than to simply give the vaccination. If the titer is adequate, the worst possible outcome is that the vaccine will be ineffective.) Other veterinarians question whether or not it is harmless to annually give vaccinations when there is already adequate immunity present. At this time there is no single answer to this issue and we recommend trusting your own veterinarian’s educated opinions regarding these issues.

PROTECTION AFTER INFECTION

A puppy that has recovered from a parvovirus infection can be expected to have strong immunity. This has been tested out to 20 months post infection and immunity is believed to be life long (though because this is unproven continued vaccination is commonly recommended).

PREVENTION BY ENVIRONMENTAL CONTROL

Because of parvovirus, puppies should not be allowed out in the public world until their vaccine series has been completed. This means not going for walks or to the park and not socializing with other puppies. There is some controversy regarding socialization of young puppies if they are kept isolated in this way until age 16 weeks; however, from an infectious disease standpoint, this is the safest way to go. If the home has previously housed a parvo infected dog or puppy, disinfection especially removing fecal matter is paramount. Please see the section on environmental decontamination for more information on this subject. By obtaining an older puppy, whose vaccination series is already complete, one can avoid this entire issue.

Page last updated: 9/30/2025