Vaccination Strategies

Question 1

does revaccination of an animal that is already protected result in enhanced disease resistance

Answer 1

NO but can result in increased risk of adverse effects

Question 2

what is the regulatory agency for veterinary biologics

Answer 2

USDA - Veterinary Biologists Program of APHIS

enforces the Virus Serum Toxin Act

Question 3

virus serum toxin act

Answer 3

outlines the 4 licensing requirements for vaccine approval:
1. pure
2. safe
3. potent
4. effective

Question 4

vaccine labeling requirements

Answer 4

single tier label claim - “effective”

labels must include a statement referring users to the product insert and/or website for product licensing data (Product Summaries website)

Question 5

what are the conditions of veterinary vaccines

Answer 5

must be safe and effective

prioritization of these gets placed differently depending on companion vs food animals

Question 6

how do food producers prioritize vaccines

Answer 6

use depends on
1. cost
2. efficacy

if vaccine does not perform or is too expensive they will not use them

Question 7

how do companion animals prioritize vaccines

Answer 7

less economic pressure than food producers

higher priority on safety and efficacy

Question 8

how do shelter settings prioritize vaccines

Answer 8

similar to food producers:
1. cost
2. efficacy

Question 9

herd immunity

Answer 9

transmission of most infectious agents will NOT continue within an exposed group of animals IF the proportion of resistant animals is above a threshold level of 70-80%

Question 10

what does herd immunity depend on

Answer 10

factors that influence likelihood of transmission:
1. animal density
2. dose of agent

even if population is vaccinated - if the density or dose/exposure is too high, the disease may still spread

Question 11

when do vaccines need to be administered

Answer 11

during a sufficient time period PRIOR to exposure

Question 12

considerations for vaccination in shelter settings

Answer 12

1. low herd immunity of animals entering shelter
2. high infection pressure
3. high density housing

Question 13

general principles of vaccination programs in shelters

Answer 13

1. MLV
2. use fewer antigens
3. protect early, more frequent, and later
4. vaccinate in expanded population

Question 14

why use modified live vaccines in shelters

Answer 14

allows for rapid onset of immunity to be generated

Question 15

how can fewer antigens be used

Answer 15

focus on pathogens with shelter transmission or public health risk
- parvo, distemper, panleukopenia, rabies

respiratory pathogen vaccines do NOT provide full protection

Question 16

timeline for vaccination in shelter settings

Answer 16

start: 4 weeks
boosters: every 2 weeks
final: 18-20 weeks

shelters have high infection pressure and animals coming in have unknown levels of maternal antibodies - want to vaccinate early, frequently, and until later age

Question 17

why vaccinate in an expanded population

Answer 17

risk of exposure is much higher in shelters than in animals in GP setting

still vaccinate mildly sick, pregnant, or injured animals