We know that vaccines are a key pillar when it comes to controlling highly contagious and potentially deadly infectious diseases, especially for puppies, who, moreover, are the ones most at risk of contracting them. That is why the news that the parvovirus vaccine does not seem to be working is worrying.
So can a vaccinated dog get parvovirus? In this article on our site we talk about parvovirus in vaccinated dogs and we explain why this contagion can happen.
Parvovirus in vaccinated dogs
The question that titles this article, that is, if a vaccinated dog can contract parvovirus, seems to be gaining relevance in recent times, since more are being reportedof usual cases of parvovirus in vaccinated adult dogs that have contracted the disease. It is the veterinarians who diagnose the dog and notify what happened to the laboratory that manufactures the vaccines or to the organisms responsible for the medicines.
Canine parvovirus is a viral disease that causes severe vomiting and characteristic bloody diarrhoea. There is no other treatment than supportive treatment and it produces considerable mortality. Hence, the vaccine against this virus is considered essential and its administration is recommended for all dogs.
Is there a new strain of parvovirus?
One of the hypotheses that are considered to explain why a vaccinated dog can contract parvovirus is the appearance of a new strain. This modification of the virus would render the available vaccine ineffective. But this assumption does not seem to be true. It is known that this virus has been changing since its discovery and different strains are already known, but their differences are minimal and, in addition, the most recent strain that is known has been circulating for years and, in fact, has become the one with a greater presence today.
It is true that this strain is not included in the vaccine that is used, but considering that it is the prevalent strain, if the vaccine were ineffective against it, there would be many more dogs suffering from parvovirus than those being counted. Therefore, the current vaccine is likely to offer some protection against the latest strain. In any case, it is being studied that small changes between strains may affect the efficacy of the vaccine.
Why does the canine parvovirus vaccine fail?
With the information currently available, the theory that can explain the cases of parvovirus in vaccinated dogs is a vaccination failure due to interference with the maternal antibodies Bitches transmit antibodies to their puppies through colostrum, which is the liquid secreted by the mammary glands immediately after giving birth and before milk. It has been discovered that if this colostrum provides a high level of antibodies, these are able to remain in the puppy for up to 12 weeks of life. It is also known that these antibodies interfere with the effectiveness of vaccination.
The goal in administering a vaccine is to stimulate the immune system to make antibodies against a particular pathogen. In the case at hand, if the vaccinated dog comes into contact with the parvovirus, it will have its defenses ready to fight it from the first moment. On the other hand, if there has been an interference, these defenses will not have been generated or not in sufficient number and, consequently, the dog will be unprotected. On the other hand, it is also known that there are dogs with immunological deficiencies or breeds with a greater tendency to this problem that will be susceptible to contracting parvovirus even if they are vaccinated.
In addition, a not entirely effective response to the vaccine that does not elicit a high number of antibodies can prevent the cross-immunity that the traditional vaccine offers against the latest strain. Hence, these dogs are more susceptible to contracting parvovirus. Finally, it should also be noted that the parvovirus vaccine must be repeated every year to maintain protection.
How to prevent a vaccinated dog from contracting parvovirus?
One way to improve the effectiveness of the parvovirus vaccine is simply to adapt the vaccination scheduleNormally, the first vaccinations given to puppies are completed around 12 weeks of age. As we have seen, it is possible that some puppies at that age still have maternal antibodies that will affect the effectiveness of the vaccine. Therefore, the current trend is to delay this schedule and give the last vaccine at 16 weeks, when maternal antibodies are no longer present.
Also with the aim of improving the efficacy of vaccination, the possible interaction produced by administering the parvovirus and Leptospira vaccines at the same time is currently being studied. It seems that putting together decreases the effectiveness against parvovirus. It is not an effect that will have repercussions in all dogs, but in those in which vaccination does not stimulate high levels of antibodies, it may be interesting to take this fact into account. The schedule that is being considered prioritizes administering essential vaccines against viral diseases and leaving those for Leptospira or Bordetella for 18-22 weeks of life.
Conclusion: do I vaccinate my dog against parvovirus?
Definitely yes Although a vaccinated dog can contract parvovirus under the circumstances we have described, the failure rate is still low in relation to all the dogs that are vaccinated each year. In addition, veterinarians have enough information to adjust the vaccination schedules of puppies in order to improve the effectiveness of each vaccine. It is important, to achieve this, that we put ourselves in the hands of a trusted professional.
