Transcript Vaccines Against Viral Infection

Vaccines Against Viral
Infection
Austin Follett
Medicinal Chemistry
Anti-Viral Vaccines
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History
Vaccine types
How they work
Recommended Schedule
Specific Vaccines
1. Flu
2. HIV/AIDS
3. Human Papillomavirus (HPV)
6. To stick or not to stick?
History of Vaccines
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Chinese inoculated themselves against smallpox before 200 B.C.
Edward Jenner inoculated against smallpox with cowpox in 1796
Vaccination comes from Latin (vacca– cow)
Louis Pasteur took the concept and applied it to prevent against
anthrax and viral rabies
• 1988: W.H.O. targets polio for eradication
• 2000: Global Alliance for Vaccines and Immunization formed;
strengthens routine vaccinations in countries with GDP below
$1000
• Currently, nearly two dozen vaccines are available for use in the
United States
Types of Viral Vaccines
1. Inactivated: Virus particles are grown
then killed by either heat or
formaldehyde
2. Attentuated: Live, weakened form of
the virus particles
3. Subunit: Only given antigen of virus
1. Isolation of specific protein
2. Recombinant administration
How vaccines work
Vaccination Schedule
• By age two, children are recommended
to have the following vaccines by the
Advisory Committee on Immunization
Practices:
– Hepatitis A & B, Polio, Measles, Mumps,
Rubella, Diptheria, Pertussis, Tetanus, HiB,
Chicken Pox, Rotavirus, Influenza,
Meningococcal disease, and Pneumonia
Flu Vaccine
• Virus has 8 piece
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genome undergoes
antigenic drift
The flu kills 36,000 in
the US annually
Flu vaccine is an
educated guess of the
most probable form of
virus
Two main types:
– Flu shot: inactivated
vaccine
– Nasal-spray: attentuated
vaccine
Should you get vaccinated?
• Yes, if you are at high risk or care for
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someone who is
No, if you are allergic to chicken eggs or are
otherwise immunocompromised
Side effects:
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Possible virulence from nasal-spray
Soreness, redness
Low-grade fever
Aches
HIV Vaccine
• An effective HIV Vaccine would allow the
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body to completely rid itself of the virus
and/or control it to prevent infection and
transmission
Three types being used: subunit, recombinant,
and DNA vaccines
http://www.hopkinsaids.edu/hiv_lifecycle/hivcycle_txt.html
HIV Methods of Prevention
• Prevent fusion to host cell
• Inhibit reverse transcriptase
• Inhibit integrase: no viral integration
into host genome
• Target protease: prevent polypeptide
cleavage, functional HIV proteins
• Prevent release from host cell
Where’s the vaccine?
• Several challenges arise with development:
– HIV continually mutates and recombines
– HIV infects Helper T cells
– Can be transmitted as both free virus and in
infected cells
– Researchers are unsure what constitutes an
effective immune response to HIV
– No ideal animal model for testing exists
– Possibility that HIV is not the true cause for
AIDS
Human Papillomavirus Vaccine
• HPV is required in the
development of nearly all
types of cervical cancer
• Vaccination prevents initial
infection by several of the
most commonly sexually
transmitted HPV types
• Estimated that 50% of men
and women will become
infected with one of the
sexually transmitted HPV
types during adulthood.
• Along with cervical cancer,
HPV can cause skin and
genital warts as well as anal
cancer and penile cancer
The Vaccine
• All types of HPV do not
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cause cancer, but a
vaccine has been
developed that protects
against types 6, 11, 16 and
18, which cause 70% of
cervical cancers and 90%
of genital warts combined
However, other types can
cause the cancer, so Pap
smears are recommended
to prevent cancer
development
Gardasil
• On February 2, 2007 Texas Governor Rick Perry mandated that
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all school girls going into sixth grade be vaccinated
Studies have only been done in short duration, long-term impact
unknown
In 2006, estimated that 9,700 women developed cervical cancer,
38% died
Although all cervical cancer types are not covered by this
vaccine, this prevalence would be greatly reduced by widespread
vaccination
Currently, multiple groups nationwide question the value of the
vaccine as a whole; safety issues seem to have fallen under the
importance of speed.
In addition, other high-risk HPV types can circumvent the
vaccine completely, reducing its effectiveness.
Controversy:
To Stick or Not To Stick?
To:
• Vaccinations prevent
viral infections, most
effective way of disease
prevention
• Cost-effective method
to manage healthcare
• Herd immunity could
extend to those that
don’t get the vaccine
Not to:
• Certain vaccinations
have not been tested
completely
• Compulsory vaccination
represents excessive
government interaction
• Childhood vaccinations
contain mercury, which
has a possible
connection with autism
(MMR, DTP, HiB, Hep. B)
Thank you!
Be smart about your
vaccinations!