Lecture 9: Vaccines Flashcards
Prevention and eradication and control of infectious diseases. Goals here today are to introduce class to vaccines, their types, pros and cons, immunity, and efficacy and impacts on human health.
Active immunity
Protection is make in someone as a result of exposure to antigen or pathogen (natural infection or vaccine)
Passive immunity
Pre-formed protection provided when an individual receive antibodies from someone (breast milk)
Describe the vaccine pathway to infection?
Infected, disease, immunity. Vaccine bypasses the disease step
Vaccines stimulate our immune system to make ______ without leading to _________
Antibodies, infection caused by the pathogen
Following a vaccine, a patient faces secondary exposure to disease A. What happens?
A secondary response to the second exposure is faster and leads to more antibody production than we saw in the initial exposure from the vaccine.
Primary response
7-14 days
Anamestic response
1-2 days
Live-attenuated vaccine
Highly effective, contraindicated in immunocompromised and pregnant.
What types of disease can LA vaccines protect patients from?
Mumps, measles, rubella, VZV, rotavirus, yellow fever
Inactivated Vaccine
Not as immunogenic as live vaccines and usually need a few boosters
What are some diseases that a killed vaccine can protect patients from?
Hep A, Influenza
Polysaccharide Vaccines
Affect the outer coating of a vaccine. Not very immunogenic and require frequent boosters.
What are some diseases that a poly-vaccine can protect patients from?
Heb B, pneumococcal 23
What are some detriments to a polysaccharide vaccine?
Elicits few T cell immune responses in kids under 2, doesn’t alter bacterial carriage, progressive boosters might not elicit same quality of immune responses.
Toxoid Vaccines
Made of bacterial toxins that are rendered harmless to protect against activity of toxins
Subunit Vaccines
Immune responses to part of the pathogen.
-Protein subunits
-Good T-cell immunity and leads to reduction in organism carriage
mRNA Based Vaccines
-Viral genetic code is used to develop the vaccine
-Vaccine leads to protein production which issued by T cells to destroy diseased cells
Recombinant Vector Vaccines
Use one virus to transport proteins of another virus into pt. Strong immune responses, issues finding viral vectors that don’t have pre-existing immune responses
What are some inDEVO DNA vector vaccines being developed?
WNV, HIV, measles, malaria, ebola
What are some characters of a good viral vector?
Safe, low toxicity, can be cell specific, stable over time, not integrate with host DNA, immunogenic with little pre-existing immunity
Properties of a good vaccine
Stable, easy to transport, long term protection, inexpensive
Basic summary of how a vaccine works?
-Presents the antigen or foreign proteins to the host
-Host T-cell or antibody response (fluid form with preservatives and stabilizers so they can can be stored over time)
-Typically proteins need to be carried on immune agonists (adjuvants)
What is an adjuvant
Immune agonists that can elicit strong immune response. This is things like typhoid toxin, alum
Example of live attenuated
Varicella, mumps, measles
Example of subunit vaccine
Bodetella pertussis
Toxoid toxin example
tetanus and diphtheria
Example of polysaccharide vaccine
streptococcus pneumococcus, N. meningitis
mRNA vaccine example
SARS-CoV-2
Recombinant DNA vaccine example
Hep B
Individual protection
Protects whoever took the vaccine
Community protection
Vaccination of a large proportion of the population allows for a reduction in the chances of non immune person becoming infected as well (herd immunity)
How much of the population must be vaccinated to achieve herd immunity?
70-90%
Vaccination may not lead to reduction in carriage this means…
Pathogen can still be circulating despite high levels of vaccination
What are some things that can affect vaccine efficacy?
Vaccine compliance, environmental factors, persons immune status, how infectious the disease is
Passive immunization
Temporary protection. Directly give them someone else’s or lab antibodies. When there is no time to wait for vaccine induced response. This is an outbreak, severe infection, PEP
Challenging to prepare since you need to ensure that the passive immunization form is free of all infectious agents
Describe some situations where we may use passive immunity to protect patients?
Hep A/B, VZV, Measles, rabies, tetanus, diphtheria
What is the most effective public health intervention?
Vaccines
HPV: What is it? When does it rise?
STI, rise in infection rates in young, sexually active population, usually asymptomatic infection and cleared by immune system. This can progress to cervical cancer
What is the development of cervical cancer from HPV linked to?
Ability to the virus to disrupt normal cell-cycle control which promotes uncontrolled cell division and accumulation of genetic damage
Describe the basis of protection from HPV in the vaccine?
Neutralizing serum IgG that transudates from capillaries to genital epithelial mucosa and then bind to the viral particle
Efficacy of HPV vaccine
96
What virus causes shingles?
Varicella zoster from chicken pox. You don’t need to be re-infected to develop shingles
Who is the shingles vaccine given to?
Anyone over the age of 50
