Question

1- How do the human and animal vaccine industry differ in terms of equipment, manufacturing processes, safety, and food and drug administration approval?

2-What is the difference between the lethality for biological weapons and chemical weapons? What is the difference in the mass (give approximate values) needed to attack 10 square kilometers between a biological weapon and a chemical weapon?

3-What would you do if you survived a 10 kT nuclear blast about 2 miles away from your building? Describe what you would have been exposed to during the blast.

Answer 1

Although vaccines have universal importance, approaches to human and veterinary vaccine evaluation differ markedly.

For humans, "vaccine potency"  is the capacity of the vaccine as measured by a laboratory test and "vaccine efficacy" is the percentage decrease in incidence of diseases attributable to vaccination.

For animals, "vaccine potency" is the relative strength of a biological product as determined by appropriate test techniques and "vaccine efficacy" means the ability of the vaccine to give protection against the adverse effects of the infection to the vaccinated animal.

Stages of evaluation:

Human vaccines, usually, undergo initial evaluation in animal models followed by a successive controlled trials (phase I, II and III) with an increasing number of human subjects to assess safety, immunogenicity and then efficacy.Evaluation of such information is done before allowing vaccines to be introduced. When vaccines are used in a state-funded programme, it's cost-effectiveness will also be checked. After a human vaccine is introduced, protection in the field against natural challenge is estimated, called vaccine effectiveness (phase IV).

For animal vaccines to obtain market authorization, they are first subjected to safety and immunogenicity studies on a limited no. of individuals of the target species. Ability of a vaccine to protect is assessed by in vivo challenge or occasionally by sero-conversion studies. Although they are used in the assessment of efficacy, the scale of animal vaccine field studies are much less compared to human vaccine trials.

Challenging humans with harmful pathogens is usually not acceptable but challenge studies related to animal models are important for the initial evaluation of these vaccines. Challenge studies with human subjects are only performed for pathogens with effective treatments, such as specific strains of malaria. Human challenge is also used to assess protection against an attenuated pathogen, for example oral polio vaccine.

The evaluation of animal vaccines relies heavily on challenge studies. Typically, protection is assessed using a high level of pathogen challenge with the lowest vaccine antigen content permitted under the authorization