Types of Vaccine Flashcards
What are live attenuated vaccines?
Weakened viruses/ bacteria. Achieved by growing numerous generations in laboratory conditions. Stimulates immune system to react as it does to natural infection. Produces long lasting immune response after one or two doses. Can cause mild form of the disease e.g. mini measles which is not transmittable. CANNOT be given to immuno-compromised person e.g. BCG/ MMR/ varicella/ yellow fever.
What are inactivated vaccines and toxoids?
When adequate attenuation of live virus is not possible the vaccine is inactivated by chemical processor or heat. Toxoids are toxins that have been inactivated and chemically modified. Cannot cause the disease they are designed to protect against. Doses two or more doses plus booster doses usually required.
What conditions can affect response to vaccines?
Simultaneous administration of immunoglobin, immunosuppression, sickle cell disease and causes of hypersplenism, malnutrition and chronic disease, nephrotic syndrome, prematurity (some evidence premature babies may have sub-optimal response to Hib and Hep B vaccines but should be scheduled on basis of their actual date of birth.
What is herd immunity?
The indirect protection from infection of susceptible members of the population, and the protection of the population as a whole, which is brought about by the presence of immune individuals. To achieve herd immunity the percentage of individuals who need to be vaccinated depends on the disease and the vaccines used. Only for transmissible infectious diseases.
What are the dynamics of transmission?
If an infection is to persist, each individual must, on average, transmit that infection to at least one other individual. If this does not occur, the infection will disappear progressively from the population.
Why is herd immunity important?
No vaccine is 100% effective e.g. measles vaccine is 90-95% effective so out of every 100 children given the vaccine 5-10 will not be protected. Some people unable to recieve live vaccines e.g. the immunocompromised. H
