Contain inactivated toxin (toxoid) that are produced by the microbe or purified surface component of the microbe that have been made harmless
-Corynebacterium diphtheria toxoid vaccine (DPT)
-Clostridium tetani toxoid vaccine (DPT)
-Pneumoccal capsular vaccine (PPV), pool of 90 different types of purified capsules
What are recombinant vaccines?
Genes for desired antigens are inserted into a vector, usually a virus that has a very low virulence. The vector expressing the antigen may be used as the vaccine, or the antigen may be purified and injected as a subunit vaccine
-Hep B Virus (HBV) vaccine, a recombinant subunit vaccine
What is herd immunity or community immunity?
-Refers to a reduction in the probability of infection of susceptible members of a population when a significant proportion of the individuals are immune
-This reduction is observed because the chance of coming in contact with an infected individual is less. In other words, disease transmission is blocked when a critical percentage of the percentage of the population has been vaccinated
-Measles viral vaccine is only 90% effective but other 10% are protected because virus is not being spread around
-Depending on the disease, need to vaccinate 75-95% of population to induce herd immunity
What information is contained in the MMWR?
Death rates and vaccines
What is Pertussis?
-Gram negative, coccobaillus with a capsule.
What is the pathology of pertussis?
-Highly contagious bacterial infection that causes a severe cough
-Major cause of morbidity and mortality among infants and children in the US during the 1940s
-Infants less than a 1 are most susceptible, not a lot of antibodies
-Binds to ciliated epithelial cells, and releases toxin and damages cells.
What are the symptoms of pertussis?
-Disease start with symptoms similar to common cold
-Whooping cough (paroxysms) cause lack of oxygen. Gagging and vomiting may occur after severe coughing spells. May be worse at night and lead to death
What is the DTP vaccine?
-1942 American scientist Pearl Kendrick combined the whole-cell pertussis vaccine with diphtheria and tetanus toxoids to make DTP.
The pertussis portion of DTP shot was killed B. pertussis bacteria
-Though effective, the P vaccines caused unwanted neuro side effects
What happened after the DTP vaccine?
-Vaccine discomfort permeated the publics state of mind during the late 1970s/1980s. Vaccinations dropped and pertussis causes rose!
-This started DTap, acellular (toxoid and component) were developed
-The first DTap, approved in 1991 and was shown to be just as effective with no major side effects.
-DTP removed from American market in 2001
What is the biology of Corynebacterium Diphtheriae?
-Gram positive bacillus, with cell sticking together to odd shapes called chinese letter appearance
What is the pathology of diphtheria?
-Very contagious and potentially life-threatening infection that usually attacks the throat and nose. More serious can attack the nerves and heart
-Bacteria live in upper respiratory tract, person to person transmission via droplets
-During its growth, produces a toxin that is carried in the bloodstream
-Coded by a bacteriophage called corynephage which gives the bacteria the extra gene to produce the toxin.
-Toxin inhibits protein synthesis of hose cells and may damage heart and nervous system
What are the symptoms of diphtheria?
-Early symptoms are sore throat and mild fever which progresses to lymphadenopathy of the neck and a pseudomembrane that forms over the throat and tonsils that make it hard to swallow
-Can lead to asphyxiation.
What is the vaccine of diphtheria?
-Toxoid of organism
-Protects almost everyone who has received full series of recommended doses. The number of people with diphtheria has fallen from 206,939 in 1921 to only a few year in the US
-ONLY transferred from person to person in aerosol form.
-Upon infection it resides in mucosal membrane by attaching with its pili. It then infects deeper into the tissue until it gains access to the bloodstream where it travels to infect the meninges of the brain. -Only bacteria known to cause epidemic meningitis
-Affects individuals aged between 3 years and adolescents
What is the Waterhouse-Friderichsen syndrome?
-Massive usually bilateral, hemorrhage into the adrenal glands (lose it) caused by severe meningococcemia
What is the invasiveness of N. Meningitidis?
-Infection of the nasopharynx is usually subclinical and resolves within several weeks.
-In a few individuals it invades the circulation and causes clinical disease:
1. An uncomplicated bacteremic process
2. A systemic infection that commonly involves the meninges- 3% mortality rate
3. A very severe systemic infection (meningococcemia) with circulatory collapse and disseminated intravascular coagulation (DIC) with petechial rash
What are symptoms of N. Meningitidis?
-Necrosis and vascular collapse
What is the therapy for N. Meningitidis?
-Penicillin is the drug of choice to treat meningococcemia and meningococcal meningitis
-Must diagnose quickly
-Rifampin for chemoprophylactic use for exposed individuals
How many types of N. Meningitidis are there?
-12 types capsular LPS that cause human disease
-Most important serogroups are A, B, C, Y, and W135
-Serogroup B causes the most cases in USA. NO vaccine too similar to own tissue