June 17, 2016
貓疫苗: 我們必須停止過度注射疫苗 (下)Vaccines for Cats: We Need to Stop Overvaccinating
Lisa A. Pierson, DVM
作者: 獸醫 Lisa A. Pierson, DVM
(Some of this dialog is also stated in the above sections.)
What are some of the factors that influence our decisions regarding which vaccines to use and at what frequency?
I will say at the outset of this discussion that my indoor-only cats (age range is 13-18 years) have not been vaccinated since they were 4-6 months of age. They have never set their paws outside and never will - barring a catastrophic event.
My barn cat (17 years of age) received his last FVRCP vaccine at the age of 5 or 6 months and received a FeLV series at around 6 months of age (before we knew how dangerous adjuvants can be; PureVax was not around at that time), and is vaccinated with PureVax rabies vaccine approximately every 3-4 years.
Please note that I do not administer more FVRCP vaccines to my barn cat than I do to my indoor-only cats. This is because the panleukopenia immunity from the FVRCP vaccine lasts for life in the vast majority of cats and I do not feel that the minimal amount of protection the herpes and calici fraction may provide is worth the downsides of the vaccine. Remember, it is all about risk-benefit analysis and a person's individual comfort zone.
Now, having confessed my cats' minimal vaccine history, I will state that what is 'right' for me and my cats, may not be 'right' for you and your cat(s).
Issues to consider: 考量因素
- age of patient 貓的年紀
- risk of exposure to the disease in question 曝露於預防針所預防的疾病的風險
- prevalence of the disease in the environment 環境中預防針所預防的疾病的普及率
- consequence of the infection 發炎的後果
- overall health of the patient 貓的整體健康狀況
- vaccine efficacy疫苗的效果
- DOI studies (Duration of Immunity) for the vaccine疫苗免疫期的研究
- vaccine properties (adjuvanted/non-adjuvanted， etc.)疫苗種類（有無佐劑等）
- titer testing測驗力價
- owner's comfort level 主人認為妥善舒服的做法
This certainly does not sound like a very scientific factor but it is an important issue to consider. Given the fact that all foreign substances do have side effects when introduced into any living being, I would be a hypocrite if I did not mention the owner's feelings since my own comfort level is tested anytime I decide to inject anything into the body of my own cats or that of my patients.
Now having said that, we can't throw the baby out with the bathwater and not vaccinate at all otherwise, our cats (and possibly their humans in the case of rabies) may suffer for it.
Now, for the science: 現在，就科學觀點而言：
- Age of the patient: Maternally-acquired immunity is an important concept to understand. When a kitten nurses from his mother, the first milk that she produces (colostrum) is rich with antibodies to fight the various diseases that the mother has been exposed to either naturally from her environment or from any vaccines that she has received prior to giving birth.
(Hopefully all owned cats have been spayed/neutered so as not to contribute to the tremendous overpopulation problem in this world. Therefore, most cats that have given birth are unowned or wild (feral) cats that have not been vaccinated and only carry antibodies to diseases present in their own environment.)
Maternal antibodies acquired by the kitten inhibit his ability to fully respond to a vaccine. These antibodies diminish over time and by 16 weeks of age, are at a low enough level in nearly all kittens to allow their immune system to adequately respond to a vaccine. (Most kittens can respond to a vaccine by 8 weeks of age but we 'pad' it a bit to cover those kittens with longer-lasting maternal antibodies.)
Therefore, the last vaccine in the 'kitten series' should be given when the kitten is at least 16 weeks of age.
Current conventional protocol states that you can start to vaccinate kittens as early as 6 weeks of age but it would be a very rare situation that would cause me to start vaccinating a kitten at such a young age.
I find that most kittens that are presented for vaccination are kept indoors and are well-isolated from disease. If the kitten resides in a protected indoor environment, I feel comfortable starting the vaccine series later than the conventional protocol calls for. This means that I may not start a kitten's vaccines until he is ~9-10 weeks of age, with the second vaccine given at 16 weeks of age.
- Risk of exposure: Does your cat go outside or is he inside 100% of the time? If he goes outside, is he likely to come in direct contact with other cats? Is your neighborhood heavily populated with outdoor cats? How prevalent is rabies in your area? Etc....
Keep in mind that even though my barn cat is outside and technically has a higher risk of exposure, given the duration of immunity of the panleukopenia vaccine, he is not vaccinated with FVRCP any more frequently than my indoor-only cats.
- Prevalence of the disease: The most important disease to consider under this heading is rabies; its geographic prevalence varies widely.
- Consequence of the infection: An infection with herpes or calici is far less serious than an infection with panleukopenia or rabies. Also, keep in mind that the herpes and calici vaccines do not protect the recipient from infection since their efficacy is not as strong as the vaccines for panleukopenia and rabies. Herpes and calici vaccines only lessen the severity of symptoms but will not prevent infection. This is an important fact as it pertains 屬於to the risk-benefit analysis. (The risk of sarcoma, kidney inflammation, etc., outweigh the small, if any, benefit of frequent re-vaccination.)
- Health of the patient: Vaccines are to be administered only to healthy patients.
- Previous vaccine reactions: All past vaccine reactions - no matter how minor - must be taken into consideration when making future vaccine decisions. Under most circumstances, I will not re-vaccinate a patient that has had an allergic reaction since the next time may bring on a more serious reaction.
- Vaccine efficacy: Vaccines vary in their ability to confer strong immunity within the patient. Some vaccines, such as the FIV (Feline Immunodeficiency Virus) vaccine are not very effective at stimulating immunity in the recipient. In addition to this issue, the FIV vaccine is a killed product which means it contains an adjuvant. Therefore, it should not be administered to any cat, in my strong opinion, due to the risk of VAS.
As noted above, Herpes and calici vaccines are also lacking in the ability to induce complete protection. At best, they will only reduce the severity of some symptoms but will not prevent infection with these viruses and will not protect the recipient from all symptoms of disease. The risks of repeated vaccination outweigh the benefits in most situations.
- Duration of immunity (DOI): The duration of immunity (how long a vaccine protects the recipient) varies with each disease/vaccine and, of course, with each patient. However, one vaccine that we do have strong data for is the panleukopenia vaccine which is a very good thing considering how contagious this fatal disease is.
From two different studies, we know that the panleukopenia vaccine confers immunity for at least 7.5 years (the study was stopped at that point) and most immunologists feel that the vaccine lasts for life in the vast majority of cats. If a cat falls into the rare category of not being protected for life, it is thought that this cat is a 'non-responder' and may fail to respond even if further panleukopenia vaccines were given.
All that said, panleukopenia is a nasty disease and if I had a cat that was going to be exposed to, for example, foster cats and that cat had not been vaccinated for panleukopenia within the previous 8-10 years, I would consider re-vaccinating. Or, better yet, do not allow the cat to be exposed to other cats of unknown vaccination/infection status.
- Vaccine properties: As I have stated many times, I do not use an adjuvanted vaccines.
- Titers: Note that titer testing is only done for panleukopenia and rabies (for international shipping) and not for herpes and calici.
Think of the immune system as a 'gun' and antibodies as 'bullets' for the gun. A titer measures the amount of antibodies for a specific disease that are currently circulating in the blood stream of the body. This sounds like a great test but the information we get from titer testing is only part of a much bigger picture.
Notice that I emphasized the word "current" in the paragraph above. This is because of 'memory cells' which are cells in the body that titer testing cannot measure. Memory cells are primed by a previous natural exposure or vaccination to a pathogen (virus, bacteria, fungus, etc.) and are ready to quickly (within hours) produce more antibodies the moment the body is exposed to the invader again. These cells do not produce antibodies - and therefore, do not contribute to the titer level - until the body is attacked by the pathogen.
Antibodies are not the only type of 'bullet' that the immune system uses. There is another type of 'ammunition' called cell mediated immunity (CMI) which is a very important arm of the immune system that, unfortunately, we cannot measure with any commercially available test - including a titer test.
Given the above, it is obvious that titer testing has some severe limitations when being used to assess the status of a patient's immune system. If a titer is low, that does not necessarily mean that the patient is unprotected. If he has a lot of memory cells standing by waiting, he is considered to be well-protected against diseases that are best eliminated with a quick antibody response.
從以上的訊息我們可以知道，要判讀病人體內的免疫系統狀態，力價測驗能力有限. 如果力價很低，並不表示測驗者沒有受到保護. 如果測驗者體內有很多記憶細胞在待命，表示身體有受到很好的保護，體內迅速的抗體反應可以消滅入侵的疾病.
So when may titer testing be helpful?
As discussed above, two examples are:
- to decide if you want to give the 1-year booster after the last kitten vaccine
- to decide if you want to vaccinate an altered adult cat that came to you with an unknown vaccine history
If an UNaltered stray cat ends up on your doorstep, chances are that he or she has not been vaccinated - and should receive a vaccine now.
Titer interpretation: 解讀力價：
If a cat shows any titer at all, this means that he has either been vaccinated in the past (and responded to that vaccine) or he has been naturally exposed to the disease.
According to the World Small Animal Veterinary Association Vaccine Guidelines Group (WSAVA-VGG), a positive test result would lead to the conclusion that revaccination is not required.
Note that a low (versus high) titer does not necessarily mean the cat is unprotected since memory cells and cell mediated immunity are, in all probability, present in full-force. This is very important to understand because the advent of titer-testing has led to unnecessary revaccination of many patients just because they came up low on their titer test.
A negative titer means that the cat may, or may not be, protected. The WSAVA-VGG recommends vaccinating these cats while acknowledging that these patients may be fully protected and not need to be vaccinated. They are, understandably, taking a 'better safe than sorry' approach since panleukopenia is such a serious disease.
If a cat with a negative titer is subsequently vaccinated (with a properly manufactured and handled vaccine) and has his titer re-checked with another negative result, this patient would fall into the 'non-responder' category and should not be vaccinated again.
I wish that I could tell you that there are a straight-forward, clear-cut answers for all decisions involving the vaccination of our cats but there are simply too many variables involved to make this a reality.
As noted above， please understand that I cannot offer any advice via email. If you wish to discuss your personal situation， I am available for phone consultations as noted at the bottom of this web page.
In closing， I would like to see less money being spent on over-vaccination of our cats and more money being spent on dental health care which will be the subject of my next webpage.
Preview: Please consider brushing your cat's teeth since it is the very best way to maintain their dental health.
And please do not subject your cat to anesthesia-free dental cleanings which provide very little benefit since the problems are under the gum line and these 'awake' cleanings only serve to stress your cat and your pocketbook for very little， if any， benefit.
(No cat is going to let a human probe and clean under their gum line.)
These anesthetic-free cleanings simply result in is a false sense of security leading the cat owner to believe that they have adequately addressed their cat's dental needs.
Supporting research regarding vaccinations - 2 abstracts:
關於疫苗的研究 － 摘要兩則
I put some text in bold. Please note that Dr. Ron Schultz is one of the leading experts in immunology and is highly respected.
有些內文我用粗體字。舒爾茲獸醫（Dr. Ron Schultz）是免疫學的領導專家之一，而且備受尊重。
J Comp Pathol. January 2010;142S1(0):S102-S108.
R D Schultz1， B Thiel， E Mukhtar， P Sharp， L J Larson
1 Department of Pathobiological Sciences， School of Veterinary Medicine， University of Wisconsin-Madison， Madison， Wisconsin， USA.
譯註：上面這段的第一行指出原文出處．J Comp Pathol 是一個醫學期刊，全名是 Journal of Comparative Pathology．至於 January 2010表示是２０１０年一月出版.
Vaccination can provide an immune response that is similar in duration to that following a natural infection. In general, adaptive immunity to viruses develops earliest and is highly effective. Such anti-viral immune responses often result in the development of *sterile immunity and the duration of immunity (DOI) is often lifelong.
疫苗所提供的免疫力，和得過病而具備的免疫力，兩者是類似的. 基本上，最早出現的是針對病毒的後天免疫力（或稱適應免疫力），而且極有效率. 如此的抗病毒免疫反應，其結果帶來的是全面免疫力，而且免疫期往往是終生持續.
In contrast, adaptive immunity to bacteria, fungi or parasites develops more slowly and the DOI is generally short compared with most systemic viral infections. Sterile immunity to these infectious agents is less commonly engendered.
*Dr Pierson's comment: "Sterile immunity" refers to the immune system preventing infection with the offending agent. "Non-sterile immunity" refers to the fact that the pathogen can still infect the body (herpes and calici, for instance) but the clinical signs will not be as severe in a vaccinated animal when compared to an unvaccinated animal. End comment.
Old dogs and cats rarely die from vaccine-preventable infectious disease, especially when they have been vaccinated and immunized as young adults (i.e. between 16 weeks and 1 year of age). However, young animals do die, often because vaccines were either not given or not given at an appropriate age (e.g. too early in life in the presence of maternally derived antibody [MDA]).
More animals need to be vaccinated to increase herd (population) immunity. The present study examines the DOI for core viral vaccines in dogs that had not been revaccinated for as long as 9 years. These animals had serum antibody to canine distemper virus (CDV), canine parvovirus type 2 (CPV-2) and canine adenovirus type-1 (CAV-1) at levels considered protective and when challenged with these viruses, the dogs resisted infection and/or disease.
Thus, even a single dose of modified live virus (MLV) canine core vaccines (against CDV, cav-2 and cpv-2) or MLV feline core vaccines (against feline parvovirus [FPV], feline calici virus [FCV] and feline herpes virus [FHV]), when administered at 16 weeks or older, could provide long-term immunity in a very high percentage of animals, while also increasing herd immunity.
- Membranoproliferative glomerulonephritis possibly associated with over-vaccination in a cocker spaniel.
Ortloff A, Moran G, Olavarria A, Folch H. J SMALL ANIM PRACT 51:499-502, 2010.
This report described a clinical case of membranoproliferative glomerulonephritis (MPGN) in a young dog. The 7-month-old male cocker spaniel presented to the veterinary clinic with vomiting, diarrhea, lethargy, and anorexia. The puppy had been previously healthy with no prior disease, drug treatment, or toxin exposure. However, the puppy had been vaccinated by the owner (without veterinary direction) a total of 7 times (once per month) with a distemper/hepatitis/leptospirosis/ parainfluenza/parvovirus (DHLPP) vaccine.
這份報告描述的是一隻小狗的膜增生性腎小球腎炎． 七個月大的可卡公犬被帶到醫院時，症狀有嘔吐、腹瀉、沒有精神以及厭食. 之前健康狀況良好，沒有任何病史和用藥歷史，也沒有曝露在有毒的環境中. 但是小狗被主人（在沒有獸醫的指導下）施打了七次五合一疫苗，一個月一劑.
The puppy was severely dehydrated on clinical presentation and demonstrated pale mucous membranes, oral ulcerations, halitosis, and abdominal pain. Several diagnostic procedures were performed, and ultrasonography revealed loss of renal architecture, increased cortical echogenicity, and bilaterally decreased kidney size.
Complete blood count and serum biochemical values were consistent with renal disease, including anemia, severe azotemia, hyperphosphatemia, and hypoalbuminemia. Urine culture was negative. The puppy was aggressively treated for renal failure, including peritoneal dialysis, but died 3 days after hospital admission.
Necropsy was authorized, and revealed ascites, retroperitoneal and abdominal edema, small pale kidneys, and kidney morphologic changes consistent with glomerulonephritis. Electron microscopy and immunehistochemical testing demonstrated the presence of deposits in the glomerular subendothelial spaces and the basal membrane; this was consistent with antigenantibody immune complexes.
In addition, antigens in the complexes were similar to the vaccine antigens in the DHLPP vaccine, suggesting that the glomerulonephropathy in this puppy was secondary to frequent and unnecessary vaccination.
Commentary: Although membranoproliferative glomerulonephritis is reported as 1 of the most common glomerulopathies in dogs, a definitive diagnosis and identification of the offending antigen are rarely identified due to the risk and expense associated with renal biopsies and electron microscopy.
This case report demonstrates that injudicious use of vaccinations may, like other infectious or autoimmune diseases, lead to immune complex deposition and subsequent glomerular damage.
When possible， appropriate education should be provided regarding the rationale for current vaccine guidelines to avoid overvaccination.
Further studies are required at this time to determine the role， if any， that recent past and current vaccine protocols play in the development of protein-losing nephropathies. Shawn Kearns， DVM， Diplomate ACVIM
獸醫 Shawn Kearns, DVM, Diplomate: 在此同時也出現進一步研究的必要，以決定最近的過去以及目前的疫苗準則，在造成蛋白質流失的腎病發展上，所扮演的角色。
Unfortunately， this has resulted in a significant sacrifice of my personal time and I have reached a point where I can no longer read or respond to the large volume of emails that I receive.
On a very good note， the emails make me smile because I know that the message is being heard and more cats are receiving better nutrition and care.
On the other hand， the large volume of people asking for my time has become overwhelming. Therefore， this statement will appear throughout this site as well as the bottom of every page:
No individual advice or further explanation， for any reason， will be provided via email.
That said， if you desire personalized help and would like information regarding my phone/Skype consulting service， please send your request to DrPierson (at) catinfo.org. Make sure that you put "Consultation Service" in the subject line which may help prevent your request from ending up in my spam folder and increase your chance of hearing back from me.
Partially updated October 2014
Lisa A. Pierson， DVM
本文作者獸醫麗莎皮爾森（Lisa Pierson, DVM） 於一九八四年畢業於加州大學戴維斯分校獸醫系（the University of California, Davis School of Veterinary Medicine）。目前執業以提供線上電話（skype）收費諮詢為主，包括提供病貓專用食譜。如果你想要進行諮詢，請寄電郵至 DrPierson@catinfo.org， 主旨標明 “consultation service”。(諮詢當然是以英文進行，每小時費用好像是美金二百五十到三百元之間，如果我沒記錯的話。想諮詢的人自己去跟皮爾森砍鳳，乖。. )