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Basic Vaccinology: Why Vaccines Work or Don't Work

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Dr. Dan Grooms presented this information for DAIReXNET on January 13th, 2014. For more information, please see our archived webinars page at www.extension.org/pages/15830/archived-dairy-cattle-webinars.

Basic Vaccinology: Why Vaccines Work or Don't Work

  1. 1. Basic Vaccinology: Why Vaccines Work or Don't Work Dr. Dan Grooms, Michigan State University . 1
  2. 2. Objectives Lets think beyond just giving “shots”       What are Vaccines Types of Vaccines Vaccine Failure Vaccine Handling Vaccine Risks Process of Developing a Vaccine Protocol 2
  3. 3. What Are Vaccines  Substances that are designed to stimulate an immune response that reduces the risk of a detrimental condition  Substances = antigens  Immune Response = complex response to antigens  Risk Reduction = no vaccines are 100% effective  Detrimental Condition = disease, pathology, death, etc 3
  4. 4. Vaccines Types Attenuated Killed Bactrin Autogenous Virulent Toxoids Recombinant Anti-toxin 4
  5. 5. Attenuated Vaccines     Also called “modified-live” or “live” vaccines Live replicating organism with reduced virulence Virus or Bacteria Have been manipulated to reduce or eliminate their ability to cause disease  In order to work, they must replicate!! 5
  6. 6. Attenuated Vaccines  Advantages  Closely simulate natural infection  Stimulate humoral and cell mediated immunity • Important for intracellular organisms such as viruses  Adjuvants not as necessary  Generally cheaper (Valley Vet On-Line 12-09-13) • Pyramid 5 (MLV) 10 ds = $11.99 • Triangle (killed) 10 ds = $15.65 6
  7. 7. Attenuated Vaccines  Disadvantages  Potential to cause pathology • Replicating organism can cause mild signs - Brucellosis • Intact virulence - BVDV, IBR • Potential for reversion to virulence – low, low risk  Contamination • Jencine(4-way live vaccine) contaminated with non-cytopathic BVDV  Stability 7
  8. 8. Killed vaccine  Dead organism  Bactrin = Killed bacterial suspension  Key is maintaining antigenic integrity  Usually require adjuvants to adequately stimulate immune system 8
  9. 9. Adjuvants  Aid in stimulating immune response to antigen and stabilizing vaccines  Do not confer immunity  Mechanisms  Depot – prolonged exposure • Oil adjuvants  Irritants – amplify response around target antigens • Aluminum hydroxide • Toxins • Adjuvants are not innocuous 9
  10. 10. Killed Vaccines  Advantages  Generally safer • No disease due to virulent organism • No contamination  Greater stability  Disadvantages  Hypersensitivity reactions (adjuvants, toxins or large antigen loads)  Endotoxins  More costly • Pyramid 5 (MLV) 10 ds = $11.99 • Triangle (killed) 10 ds = $15.65 10
  11. 11. Toxoid  Toxins are the major “virulence” factor of some bacteria which cause disease:  Toxoids contain chemically altered toxins  Stimulate neutralizing antibodies to the toxin  Examples  Clostridium • Tetnus toxoid • C. perfringes C & D toxoid  Mannheimia haemolytica • Leukotoxin  E.coli • Endotoxic mastitis 11
  12. 12. Autogenous Vaccines  Made against “farm specific” pathogen  Specific rules regulate their production  Can only be used on the farm that organism was derived from  Generally used when effective commercial vaccine is not available  Example • Mycoplamsa bovis • Clostridium perfringes • Staph aureus 12
  13. 13. Vaccine Failure 13
  14. 14. Vaccine Failure  REMEMEMBER - Vaccines are not 100% effective  They are a tool to use in conjunction with other disease control tools  However, there are things that can reduce efficiency  Incorrect Administration  Correct Administration 14
  15. 15. Vaccine Failure  Incorrect Administration  Label directions not followed 15
  16. 16. Follow the Directions 16
  17. 17. -Dairy DisasterThe case of not reading the label 17
  18. 18. Dairy Disaster  150 lactating cow dairy  Acute out break of pneumonia in lactating herd  Necropsy  Severe Acute Emphysematous Bronchopneumonia • Bovine Respiratory Syncytial virus • Mannheimia Pasteurella  45 vows died  Entire herd treated with Ampicillin  Lost milk for ~1 week 18
  19. 19. 19
  20. 20. Dairy Disaster  Investigation  Recent purchase of new clean-up bull  Herd had been using a modified live viral vaccine that DID NOT contain BRSV.  Admitted, they had not read the label and purchased from catalog because it was less expensive.  Primary BRSV outbreak with secondary Mannheimia haemolytica pneumonia = disaster!! 20
  21. 21. Vaccine Failure  Incorrect Administration  Label directions not followed  Correct Administration  Poor Vaccine handling 21
  22. 22. Vaccine Handling • Vaccines are biological in nature, therefore very sensitive to the environment. • Damaging the vaccine components reduces the chance of stimulating effective immune response • Improper vaccine handling = Vaccine Failure 22
  23. 23. Vaccine Handling • Store refrigerated – 40o F (4 Co) – Not a bad idea to have internal thermometer to monitor fridge temp! • DO NOT FREEZE • Transport in cooler • Stored in cooler in working area 23
  24. 24. Vaccine Handling • Protect from UV light • Keep in dark covered container 24
  25. 25. Question?  After mixing a Modified Live Virus vaccine how long is it good for? A. 4 hrs B. 4 days C. 4 weeks D. 4 months 25
  26. 26. Vaccine Handling • Mix only enough vaccine for 30 minutes of work – Live vaccines are “dead” within 4 hours after mixing 26
  27. 27. Vaccine Handling • Protect vaccine from contamination – Do not enter bottles with dirty needles – Capped needle for vaccine removal – Transfer needles for mixing 27
  28. 28. Vaccine Handling • What about syringes and needles? • Protect from heat • Never use disinfectants on syringes – Use hot water ONLY – Then let air dry • Do not disinfect needle between animals 28
  29. 29. Vaccine Failure  Incorrect Administration  Label directions not followed  Correct Administration  Poor Vaccine handling  Wrong vaccine – Clostridial vaccines  Antigenic differences – BVDV  Bad timing – Vaccination to protect fetus ½ way thru pregnancy  Overwhelming exposure – commingled situations  Animal fails to respond • • • • Immunosuppression – Post partum Genetics Nutrition Passive immunity 29
  30. 30. Vaccine Risks 30
  31. 31. Vaccine Risks  Injection site lesions 7-way clostridial vaccine given at 50 days of age, slaughtered at 18 months of age 31
  32. 32. Vaccine Risks  Injection site lesions  Type 1 hypersensitivity = Anaphylaxis = Allergic Reaction 32
  33. 33. Vaccine and Anaphylaxis  Signs in Cattle  Immediate to 30 minutes later  Acute Respiratory Distress  Muscle tremors  Salivation  Go down  Treatment  Epinephrine • 1:1000 – ¼ - ½ cc/100# IV – 1 cc/100# IM/SQ 33
  34. 34. Vaccine Risks  Injection site lesions  Type 1 hypersensitivity (anaphylaxis)  Endotoxins  Endotoxins common with gram negative bactrins  “Endotoxin stacking” – Additive effect from giving multiple gram negative bactrins  Results • • • • Anaphylaxis Sick calves Abortion Decreased milk production  Limit number of gram negative bactrins given at one time to 2. 34
  35. 35. Gram Negative Bactrins • • • • • • • Salmonella E. coli Pasteurella Mannheimia Leptospirosis Moraxella Histophilus • Vibrio • Brucella 35
  36. 36. Vaccine Risks     Injection site lesions Type 1 hypersensitivity (anaphylaxis) Endotoxins Residual virulence  Attenuated vaccines • Brucellosis vaccines RB-51 • Shedding 36
  37. 37. Vaccine Risks      Injection site lesions Type 1 hypersensitivity (anaphylaxis) Endotoxins Residual virulence Human Health Issues  Brucella abortus  Johne’s Vaccine 37
  38. 38. Designing a Vaccine Program What must be considered when deciding what vaccines to use or recommend? 38
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  40. 40. Veterinary Client Patient Relationship 40
  41. 41. Vaccines 41
  42. 42. Questions and Discussion Dan Grooms DVM, PhD groomsd@cvm.msu.edu 42

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