Bordetella pneumonia in a person from dog vaccine
An article in an upcoming edition of Transplant Infectious Disease (Gisel et al) describes a case of Bordetella bronchiseptica pneumonia in a person who had received a kidney and pancreas transplant. This person had to board her dogs at a veterinary clinic while she was hospitalized for a bowel obstruction that occurred after surgery. The clinic required her dogs to be vaccinated against Bordetella bronchiseptica, a cause of canine "kennel cough." They were vaccinated intranasally (i.e. up the nose) with a modified live vaccine comprised of live B. bronchiseptica that is modified so it is unlikely to cause disease but can still induce a good immune response. The owner developed pneumonia after returning home and B. bronchiseptica was isolated. Specific testing was not performed to confirm that the vaccine strain caused disease, so it's possible that she was infected by the normal (i.e. "wild type") B. bronchiseptica (which still would have presumably come from the dogs).
Immunosuppressed individuals are at high risk for infection by microorganisms that usually don't cause disease in otherwise healthy people. Bordetella bronchiseptica is a good example of this. Care should be taken around pets by anyone whose immune system is compromised. Here are some recommendations pertaining to kennel cough vaccination:
- Immunosuppressed individuals should not receive modified live vaccines themselves, and it is probably prudent to extend this recommendation to avoid modified live vaccination of their pets with vaccines like the Bordetella (kennel cough) vaccine.
- If vaccination for kennel cough is required for entering a kennel or vet clinic, an exemption should be sought because of the potential risk to the immunocompromised person.
- If vaccination must be performed, injectable vaccination is preferred. It doesn't produce as good immunity in the dog compared with intranasal vaccination but the risks to the immunocompromised owner would be much less.
- If intranasal vaccination with modified live kennel cough vaccine is used, immunocompromised owners should not be in the same room during vaccination. They should avoid contact with the dog's mouth, nose and face for at least a few days after vaccination and should wash their hands (or use a hand sanitizer) regularly after contact with the dog.
- If respiratory disease develops in someone exposed to a dog recently vaccinated against kennel cough, the potential for vaccine-associated disease should be mentioned to the physician.
http://www.wormsandgermsblog.com/admin/trackback/169461
I have to disagree with you on a few points on this one.
First of all, I think you're very quick to point fingers at the dogs. Although dogs are undeniably a likely source for B. bronchiseptica in human cases, there are also cases reported that have no contact with dogs or other animals for that matter. And as you've pointed out many times before, just because the pet has the same bug as the person doesn't mean that's where the person got it from (it's just one possibility). If they'd actually identified the vaccine strain in the person in this case it'd be much more convincing, but they didn't, so I would be careful making that leap.
Second, there is a flip side to using MLV Bordetella vaccine in the pets of immunocompromised individuals. The IN vaccine is supposed to provide the best protection for the animal by inducing an immune response on the mucosal surfaces of the nose/throat, which are the initial targets of the Bordetella bacteria. By NOT vaccinating an animal, especially before it goes to a kennel, you are placing the animal at higher risk for picking up wild-type non-attenuated Bordetella which 1) may make the pet sick and 2) sick or not, the animal could bring home to its immunocompromised owner. If we're convinced such an owner could get Bordetella from their dog, I'd be even more worried about the disease that could be caused by the regular Bordetella than by the vaccine strain. I do not argue that immunocompromised individuals should avoid exposure to MLV Bordetella vaccine - the recommendations for staying out of the room during the procedure and avoiding contact the the animal's face (I'd say for a week or two, not just a couple of days) are sound. But vaccinating is a controlled decision - you know when it's going to happen, and when the dog might be shedding the vaccine virus. If the dog is left unvaccinated (or even if it has injectable vaccine, which may be more effective at preventing disease than (+/- transient) colonization and shedding) then you increase the likelihood of that dog shedding wild-type virus at any particular time.
If someone wanted to be extra cautious, their dog could be vaccinated (IN) at a time when it can be looked after by another person for at least a few days, to decrease their exposure to the vaccine strain during the highest shedding period. But if you're really worried about Bordetella transmission from a dog to its owner, then I think IN vaccination should be considered to avoid more unpredictable transmission of wild-type Bordetella.
Fair enough. I agree that the degree of proof is still less than would be desired, largely because people that publish cases of B. bronchiseptica infection in humans rarely get the dogs tested. It's important to remember that the absence of definitive proof does not mean absence of risk, and given the natural ecology of the bug, it's certainly fair to assume that this is a zoonotic disease that occurs rarely but could be an issue for certain groups.
In terms of vaccination, certainly we want reduce the risk of exposure overall. However, vaccination probably isn't useful very often, and when it's needed, the less useful but still somewhat effective parenteral vaccine should certainly be an option. Your average dog is at low risk for B. bronchiseptica exposure. Even our average unvaccinated dog going into a kennel is at low risk if the other dogs are vaccinated. In a situation where the dog is being kenneled, the risks are still very low if it is not vaccinated as long as a lot of other unvaccinated dogs are not present (the herd immunity effect). Therefore, reducing the need for vaccination by avoiding high risk situations is a first step. If vaccination is required, it needs to be considered whether it is truly needed and whether an exemption would make sense and not create additional risk to the pet and boarding facility. That would be the case most of the time. If vaccination is needed, injectable vaccination is probably fine considering the relatively low risk of exposure if a good kennel is used. The most effect vaccine (intranasal) is most important when there is a high risk of exposure, and efforts should be spent to reduce getting into a high risk situation.
This is an interesting case. Unfortunately in the U.S., at least, insurance companies will not insure kennels unless they refuse to house unvaccinated dogs.
But maybe in a case like this, an in-the-home pet sitter could be used.
Virologist Christoph Scholtissek warned about the danger of live recombinant influenza vaccine viruses to species other than the target. (In that camel case, the vaccine was even supposed to be a killed vaccine, but it was not killed properly.)
http://shiningthelight.wordpress.com/2009/09/12/cultivating-a-killer-virus/
And there was a recent report of a woman getting vaccinia from live recombinant rabies vaccine in a bait for wildlife.
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5843a2.htm
(Horrible looking lesions.)
The danger of vaccinia transmission from smallpox vacinations are well known, so that one is no surprise, but I wonder if all new MLV or recombinant live virus vaccines are routinely tested for effects on non-target species?
I noticed that cats were not diagnosed with H1N1 until the live nasal spray was distributed in the area in Iowa where the first diagnosed cat lived and I wondered about that. But since then, I think a cat was diagnosed in France, and as far as I know, the U.S. is the only place the nasal vaccine is used.