Vaccination Flashcards
Who invented the first vaccine? How?
Jenner observed milkmaids who contracted cow pox were immune to smallpox
- he attempted to deliberately induce immunity and in 1796, he successfully inoculated people with cowpox (Vaccinia virus) to protect them against smallpox (Variola virus)
What are the 6 controversies around vaccinations?
- MMR causes autism
- too many vaccines for infant immune systems to handle
- toxic chemicals used to preserve vaccines
- use of fetal cells for growing the virus used in vaccines
- too many vaccines for a baby to tolerate
- natural infection produces better immunity and makes the immune system stronger
Thimerosal
preservative for multi-dosage vaccine vials
- it is ethyl mercury and it is used at very low concentrations that are NOT toxic and does not accumulate in the body and leaves the body rapidly (methyl mercury is the one that accumulates)
used in hep and influenza vaccines
5 types of vaccines
- Attenuated whole-agent
- Inactivated whole-agent and subunit
- Toxoids
- conjugated
- nucleic acid
attenuated whole-agent vaccine
living but weakend microbes with the antigen intact but no virulence factor
- closely mimics the real infection and can get a CTL response (cytotoxic)
- 95% effective and life-long immunity because it stimulates both humoral (b-cell antibodies) and cell mediated immunity (t-cell) and memory cell creation
what are some diseases that have attenuated whole-agent vaccines?
Sabin (polio), MMRV (measles, mumps, rubella, varicella)
what are two disadvantages of attenuated whole agent vaccines?
- if the microbe in the vaccine mutates back to the virulent form, it may cause disease (if the microbe used in the vaccine reverts to its original form in the body)
- cannot use for people who have compromised immunity because theres still injection of antigen that their natural immunity cannot fight off
- also –> pregnant women should NEVER GET ATTENUATED WHOLE AGENT VACCINES
Inactivated and subunit vaccines
use whole microbes that have been killed by formalin or phenol or use parts of the organism like glycoproteins to inject into the person
what are some examples of inactivated and subunit vaccines?
- rabies, Salk (polio), one of the influenza vaccines, Gardasil (empty nucleocapsids), and HepB
what are some advantages of using inactivated and subunit vaccines?
- no replication in host; safe for immunocompromised people –> there are less antigens to stimulate the immune response and there will be no presentation of viral proteins on MHC 1 and no CD8+ cell mediated response
- no worry that vaccine will revert to wildtype
- pregnant women can be vaccinated using this so that they can be immunized against influenza
what is a disadvantage of inactivated subunit vaccines?
- immunity doesn’t last as long as attenuated vaccine and boosters must be given to ensure adequate exposure to the antigen, some memory cells can be made but it is only b-cell memory and not t-helper
toxoid vaccines
toxin of the pathogen is isolated and chemically treated to preserve the antigenicity but the toxin is non-functional
toxoid (the inactivated toxin) is then used as a vaccine to produce antibodies to the toxin, not the microbe
the antibodies to the toxin then bind to the toxin when it enters the blood stream and neutralize it, preventing it from binding to the intact cell and damaging it
what are examples of diseases that are given toxoid vaccines?
Diphtheria and tetanus
what is the downside of toxoid vaccines?
requires boosters for full immunity since no memory is produced
conjugated vaccines
- used for organisms that have polysaccharide capsules (poor antigens)
- children under 2 years cant respond to polysaccharides as antigens (only can respond to proteins)
so for them to get the vaccine, polysaccharides are combined with a protein which is highly immunogenic which fools the immune system to react to the protein and get immunity from the carbohydrate