Ch. 18: Immunization and Vaccines

#3 Which type of immunity, active or passive, is provided by the following? It is naturally or artificially acquired?--vaccination

-Active -Artificially acquired

#3 Which type of immunity, active or passive, is provided by the following? It is naturally or artificially acquired?--Natural Exposure to Infectious Agents

-Active -Naturally acquired

#3 Which type of immunity, active or passive, is provided by the following? It is naturally or artificially acquired?--Inoculation with Antiserum (Immune Serum Globulin)

-Passive -Artificially acquired

#3 Which type of immunity, active or passive, is provided by the following? It is naturally or artificially acquired?--Antibodies Transferred From Mother to Fetus During Pregnancy

-Passive -Naturally acquired

#5 Define attenuated vaccine

A weakened form of the pathogen that generally cannot cause disease. The attenuated strain replicates in the vaccine recipient, causing an infection with undetectable or mild disease that typically results in long-lasting immunity. Mimics the wild-type strain and induces the type of immune response appropriate for controlling the infection. Ex) Measles, mumps, chickenpox, rubella, yellow fever and Sabin polio vaccine

#2 Define the term active immunity.

Active immunity occurs naturally in response to infections or other natural exposure to antigens, and artificially in response to vaccination.

#1 Explain what it means to have immunity (to a virus) as opposed to lacking immunity.

Active immunity occurs naturally in response to infections or other natural exposure to antigens, and artificially in response to vaccination. It provides some protection agains infection. Lacking immunity either through lack of exposure or lack of vaccinations makes someone very susceptible to infection.

#2 Why does Active immunity provides longer term protection to passive immunity?

Active immunity provides longer term protection. Once a person has been exposed to an antigen, specific B and T cells are activated and they then multiply, giving the person lasting protection due to immunological memory. Passive immunity has no memory; once the transferred antibodies are degraded, the protection is lost.

#5 Attenuated vaccine advantages/disadvantages

Advantages: -One or two doses of an attenuated agent are often enough to induce relatively long-lasting immunity. -Vaccine strain has the added potential of being spread from an individual being immunized to other non-immune people Disadvantages: -Sometimes cause disease in immunosuppressed people, and can occasionally mutate to become pathogenic again. -Usually require refrigeration to keep them active (difficult in developing countries)

#5 Inactive vaccines advantages/disadvantages

Advantages: -They cannot cause infections or revert to pathogenic forms. Disadvantages: -Because they do not replicate, there is no amplification of the dose in vivo, so the magnitude of the immune response is limited -Several booster doses are needed to induce sufficient immunity to be protective

#4 Explain how herd immunity is achieved in a population. Describe the spread of a virus in a population that does not have herd immunity versus one that does. Explain why a virus is unable to persist in a population that has herd immunity.

Develops when a critical portion of the population is immune to a disease, either through natural immunity or vaccination. The infectious agent is unable to spread because there are not enough susceptible hosts, protecting non-immune individuals. Some infectious agents can undergo antigenic variation and therefore overcome herd immunity.

#2 Describe the first vaccine, discovered by Edward Jenner in 1798

Jenner noted that milkmaids who had recovered from cowpox (a disease of cows that caused few or no symptoms in humans) rarely got smallpox. Then, in 1796, long before viruses had been discovered, he conducted a classic experiment in which he deliberately transferred material from a cowpox lesion on the hand of a milkmaid, Sarah Nelmes, to a scratch he made on the arm of a boy named James Phipps. Six weeks later, Jenner inoculated Phipps with pus from a smallpox victim, but the boy did not develop smallpox. Phipps had been made immune to smallpox when he was inoculated with pus from the cowpox lesion. In 1798, he developed the first small pox vaccine.

#2 Define the term passive immunity.

Passive immunity occurs naturally during pregnancy and through breast feeding, and artificially by transfer of performed antibodies, as in immune globulin and hyperimmune globulin. Note that passive immunity has no memory; once the transferred antibodies are degraded, the protection is lost.

#5 Inactive vaccine definition/types

Unable to replicate, but retains the immunogenicity of the pathogen or toxin. -Inactivated whole agent (eg,influenza, Salk polio, rabies), toxoid (eg, diptheria, tetanus), subunit (eg, acellular pertussis aP, HepB) and polysaccharide/conjugate (meningococcal, Hib, Strep. pneumoniae)