7- Infectious diseases Flashcards
what are vaccines
Substance that stimulates the production of antibodies and provides active immunity against one or several diseases.
- Prepared from causative agent of a disease, its products or synthetic substitute.
- Treated to act as an antigen without inducing the disease.
Active immunity
- Protection produced by individual’s own immune system.
- Acquired by natural disease or vaccination.
- Usually long lasting.
Passive immunity
- Protection provided by transfer of antibodies from immune individuals.
- Protection temporary – commonly for only weeks or months.
- e.g. RSV (Palivizumab), Varicella (ZIG), also measles, tetanus and rabies.
types of vaccine
- inactivated
- subunit and conjugate vaccines
- live attenuated
- toxin vaccine
Inactivated vaccines
involve giving a killed version of the pathogen. They cannot cause an infection and are safe for immunocompromised patients, although they may not have an adequate response. Examples are:
- Polio
- Influenza vaccine
- Hepatitis A
- Rabies
Subunit and conjugate vaccines
only contain parts of the organism used to stimulate an immune response. They also cannot cause infection and are safe for immunocompromised patients. Examples of subunit and conjugate vaccines are:
- Pneumococcus
- Meningococcus
- Hepatitis B
- Pertussis (whooping cough)
- Haemophilus influenza type B
- Human papillomavirus (HPV)
- Shingles (herpes-zoster virus)
Live attenuated vaccines x
Live attenuated vaccines contain a weakened version of the pathogen. They are still capable of causing infection, particularly in immunocompromised patients. The following vaccines are live attenuated vaccines:
- Measles, mumps and rubella vaccine: contains all three weakened viruses
- BCG: contains a weakened version of tuberculosis
- Chickenpox: contains a weakened varicella-zoster virus
- Nasal influenza vaccine (not the injection)
- Rotavirus vaccine
Toxin vaccines
contain a toxin that is normally produced by a pathogen. They cause immunity to the toxin and not the pathogen itself.
Examples are the diphtheria and tetanus vaccines.
BEWARE
Vaccines containing egg:
- Live influenza (Fluenz)
- Yellow fever
- Rabies
NOT MMR (but beware if immunosuppressed-inactivated)
routine vaccine schedule summary
- 8 weeks
- 12 weeks
- 16 weeks
- 1 year
- yearly from age 2-8
- 3 years 4 months
- 12-13 years
- 14 years
8 weeks
- 6 in 1 vaccine (diphtheria, tetanus, pertussis, polio, haemophilus influenzae type B (Hib) and hepatitis B)
- Meningococcal type B
- Rotavirus (oral vaccine)
12 weeks:
- 6 in 1 vaccine (again)
- Pneumococcal (13 different serotypes)
- Rotavirus (again)
16 weeks:
- 6 in 1 vaccine (again)
- Meningococcal type B (again)
1 year:
Yearly from age 2 – 8:
- Influenza vaccine (nasal vaccine)
3 years 4 months:
- 4 in 1 (diphtheria, tetanus, pertussis and polio)
- MMR vaccine (again)
12 – 13 years:
- Human papillomavirus (HPV) vaccine (2 doses given 6 to 24 months apart)
14 years:
- 3 in 1 (tetanus, diphtheria and polio)
- Meningococcal groups A, C, W and Y
BCG
BCG
- Offered from birth to babies are higher risk of TB
- E.g. with relatives from countries with high TB prevalence or who live in urban areas with high rate of TB
- May also be given to children arriving from areas of high TB prevalence or those in close contact with those with it
Human papilloma virus- GARDASIL
Aim to give to boys and girls before they become sexually active- reduces risk of cervical cancer
* Strains 6 and 11 cause genital warts
* Strains 16 and 18 cause cervical cancer
Toxoid vaccines (PTD): Diptheria
- Corynebacterium diphtheria
- Disappeared from the UK now
Toxoid vaccines: tetanus
clostridium tetani
toxoid vaccine: whooping cough
Bordetella pertussis
- Pertussis is always present in the community.
- Continued infectious risk because:
–> Infection does not provide lifelong immunity.
–> Vaccination protection lasts for about 6 years. - Current acellular vaccine* replaced cellular vaccine in early 2000s.
–>Protection afforded by acellular vaccine wears off more quickly.
–>Has lower incidence of side-effects. - Vaccination programme changes:
–>Infants very vulnerable before vaccinations start (<2 months).
–>UK policy of maternal vaccination at 28-32 weeks – to protect infants not themselves
killed birus: Poliomyelitis
- Poliovirus
- Enterovirus
- Lower motor neurone disease- affects single dermatomes
- Old virus was live: caused paralytic polio
- Now killed virus
Subunit and conjugate vaccines: Hep B
Subunit and conjugate vaccines: Haemophilus influenzae type b
Subunit and conjugate vaccines: pneumonococcal disease
Subunit and conjugate vaccines: meningococcaemia (neisseria meningiditis)
live attenuated: rota virus
live attenutated: MMR Rubella
Togavirus
live attenutated: MMR Mumps
paramyxovirus
live attenutated: MMR measles
morbillivirus
