Vaccine-related Suspected Adverse Reactions

Question 1

Examples of SARs in dogs

Answer 1

• non-specific reaction
• anaphylaxis
• autoimmune (AIHA)
• Hypertrophic osteodystrophy

Question 2

Examples of SARs in cats

Answer 2

• non-specific reaction
• anaphylaxis
• injection site fibrosarcoma

Question 3

Non-specific vaccine reaction

Answer 3

• usually seen in first 2 weeks of vac
• CS: pyrexia (high temp), lethargy, anorexia, lymphadenopathy (lymphnodes swell)
• presence of reaction could impact owner attude to vac and make less likley vacc following year
• showing CS demonstrate immune response e.g. metabolic activity from immune system increase body temp by 0.5-1 degC
• CS tend to resolve on own with supportive treatment

Question 4

Vaccine and autoimmune disease

Answer 4

AID = immune system attack itself (stop differentiating between self and non-self)

• in genetically predisposed animals = vac may trigger immune response followed by autoimmune disease
• other triggers involved in AID include infection, drugs, enviro factors

Question 5

Auto-immune Haemolytic Anaemia

Answer 5

• antibodies lable RBC for distruction
• exact cause unknown = possibly change in surfave antigens
• rapid development
• bone marrow attempts to regenerate
• CS; anaemic, pallor (pale mucous membranes), weak, lethargic

Question 6

Anaphylaxis (about)

Answer 6

• severe, potentially life threatening, allergic reaction that affect many body systems
• foetal calf serum appers to be causitive factor (FCS used in cell cutures for production of some viral vaccines).
• Also suspected link to atopy (genetic tendency to develop allergic diseases) and dietarysensitivities

Question 7

Typical (Type one) anaphylaxis

Answer 7

Dogs - initial excitement with urination, defication and vomiting followed by collapse, depression, coma, convulsion and death

Cats - scratching around face (due to histamine release), dysponea (cant breath well), salivation, vomiting, incoordination, collapse and death

Question 8

Type 2 anaphylaxis

Answer 8

- dermatological signs 
~ facial odema = facial swelling
~ puritis (swelling)
~ erythmia (redness of skin
rush blood supply into face, can cause asphyxiation if blood move to neck

Question 9

Hypertrophic osteodystrophy

Answer 9

• developed in some Weimaraner pups after CDV vaccination
• occurs 10 days after vac
• pathogenesis
  ~ decreased blood flow to the metaphyses (growth area of long bone)
  ~ failure of ossification
  ~ necrsis (cell death)
  ~ inflamation of bone
• signs: anorexia, depression, gastrointestinal and resp probs, swollen metaphyses leading to angular limbs (fold)
• treatment = analgesia (pain relief)
• unusual accross all dogs, even in Weimaraner breed not common but enough to be consided serious outcome

Question 10

Injection-site fibrosarcoma (cats)

Answer 10

• fibrosarcoma = sarcoma which the predominant cell type is a maliganant fibroblast
• fibroblast = cell that synthesises the extracellular matrix and collegen (structual framework for animal tissues)
• presents as masses in skin or subcutaneous tissue
• locally invasive but metatasize (spread to other parts of body) in approx 10-20% of cases
• typically cervical/intrascapular area
• local reactions (hard lump) happen straight away and resolve quickly
• fibrosarcomas take several weeks to develop ofter vac
• cats that recieve FeLV vac 5.5x more likely to develop VSS than those w/o vac
• 1-4 cats develop sarcoma per 10,000 FeLV vac given
  FeLV show no symptoms at first, pass on saliva/sex/bites = need to vaccinate to protect population, advere reaction rare

Question 11

Serological testing to assess revaccination requirements

Answer 11

• involves testing serum to quantify ab levels (titre)
• previously done routinely on pets with rabies vac (discontinued 2012) for animals entering UK which is rabies free
• dogs - DHP assesmnet to determine need for repeat vaccination
• cats - feline panleucopaenia virus, herpes virus, calicivirus assessment to determine need for repeat vac
  ~ animal presented for blood sampling
  ~ sample sent to external lab for serology
  ~ titre result sent to practice
  ~ owner informed of result
  ~ animal recieves full or part vaccine

Question 12

Advantages of serological testing

Answer 12

• individual duration of immunity
• reducution overvac
• proof for owner
• interest in in-house testing

Question 13

Issues with sereological testing for DOI

Answer 13

• cant measure cell mediated immunity (immune response dont prodyce abs but involve activation of cells (phagocytes/t-lymphocytes) in response to antigen
• snap shot of ab levels at time of testing, unknown months later as protection can reduce
• when to test
• what to do with boarderline results (revac?)
• increased demand for external labs, unable to cope?
• cost approx £20-50 for pre-vac tsting

Question 14

Opinions from vets about serological ttesting

Answer 14

• vaccine overload considered low importance
• majority would consider introducing serology as a package option
• revac every 3 years agaist DHP appear the norm