WK 10- IMMUNISATION Flashcards
How do vaccinations work
Stimulate the immune system to create antibodies/memory cells in the absence of disease symptoms
What is herd immunity
Is the resistance of a group to invasion and spread of an infectious agent, based on the immunity of a high proportion of individual members of the herd
-stops the infiltration and spread of disease, protecting those who are not immunised
What is the process of vaccine development
- Have to separate disease causing effects from the immune generating effects in an organism
- Give it to susceptible individuals in order to produce an immune response
- End up with non susceptible, immune individuals and eventually herd immunity
What are the 5 different types of vaccines
Live, Killed/inactivated, Acellular, Toxoid, Adjuvants/Conjugates
What are live vaccines
Use the attenuated (weakened by attacking the virulence factors) form of the virus. The measles, mumps, and rubella (MMR) vaccine and the varicella (chickenpox) vaccine are examples.
What are killed/inactivated vaccines
A vaccine consisting of virus particles, bacteria, or other pathogens that have been grown in culture and then killed using a method such as heat, radiation or formaldehyde–> eg flu vaccine
What are acellular vaccines
Contain generally part of organism involved in immune response that cannot replicate→ capsule, flagella, part of protein wall (no RNA/no DNA), aka subunit vaccines
What are toxoid vaccines
Contain a toxin or chemical made by the bacteria or virus. They make you immune to the harmful effects of the infection, instead of to the infective agent/pathogen itself. Examples are the diphtheria and tetanus vaccines.
How can someone who has been immunised have diptheria but not be incredibly ill
In those who are vaccinated with a toxoid vaccine against diptheria, the pathogen can be present but does not produce the toxin that causes disease, but the organism can still grow→ harmful to people who aren’t vaccinated as they will be affected by the pathogen and the toxins released
What is an adjuvant/conjugate vaccine
Agents (including other vaccines) that increase the immune response (take something the body is good at making an immune response to)
What is the transmission of measles and what is the infectious period and incubation period
- Airborne
- Infectious from prodrome (which is generally a rash) to 4 days after onset of prodrome
- Incubation period: around 10 days to onset of fever, and 14 days to onset of rash
What is the incubation period
Time elapsed between exposure to a pathogenic organism, a chemical, or radiation, and when symptoms and signs are first apparent.
What is the period of communicability
refers to the time during which an infectious agent can be transmitted directly or indirectly from an infected person to another person
What are the symptoms with measles
Prodrome (an early symptom indicating the onset of a disease or illness)- fever, malaise
-cough, coryza (Irritation and swelling of the mucous membrane in the nose), conjunctivitis, maculopopular rash starting on face and spreading to rest of body, koplik spots
What are the complications of measles
otitis media (9%), pneumonia (6%), diarrhoea (8%), acute encephalitis (0.1%)→ mortality 10-15%, up to 40% of survivors with permanent neurological sequelae, SSPE- rarest- (Subacute sclerosing panencephalitis- brain inflammation)→ 7 years post infection, universally fatal
What is the vaccine schedule with measles vaccinations
Given in MMR/V vaccine
- 1st dose at age 12 mos
- 2nd dose at age 18 mos
- Catch up 2nd dose to age 4 (now changed to second dosage being given before age 4)
What is the transmission of rubella
Airborne droplet spread, contact with mucus membranes
-Infants with CRS shed virus in pharyngeal secretions and urine
What is the
- incubation period and
- period of communicability of rubella
Incubation; get symptoms after 14-21 days
Contagious: 1 week before and 4 days after appearance of rash
What is congenital rubella syndrome
90% of babies in womb when the mother gets rubella will develop CRS- can result in hearing loss
What are the symptoms of rubella
Generally mild, self limiting (which means that people generally consider their symptoms low and therefore move around-spreading disease), Low grade fever, Headache, Malaise, Coryza, conjunctivitis, Lymphadenopathy, Arthralgia, Rash