Immunization Flashcards
PASSIVE immunity
Uses pre-formed antibody to protect against infection.
Natural passive immunity: occurs in the placental transfer of maternal antibodies to the foetus.
Acquired passive immunity: includes treatment with immunoglobulins e.g. hepatitis B, rabies, tetanus, varicella zoster.
ACTIVE immunity
Follows exposure to an antigen, which generates an adaptive immune response.
Natural active immunity: occurs following infection.
Acquired active immunity: is provided by vaccination.
Vaccination: Overview
- Routine vaccinations in the UK are offered to everyone.
- Additional vaccines are offered to specific vulnerable groups.
- Immunosuppression is a contraindication to live vaccines due to the risk of disseminated disease.
- This includes immunodeficiency, immunosuppressive treatment and HIV.
- Inactivated vaccines can be given but the antibody response may be less.
UK vaccination summary: Children
- Diphtheria (6-in-1)
- Tetanus (6-in-1)
- Pertussis (whooping cough) (6-in-1)
- Polio (6-in-1)
- Haemophilus influenza B (Hib) (6-in-1)
- Hepatitis B (6-in-1)
- Pneumococcal
- Rotavirus
- MenB
- MenC
- MMR
- Influenza
- HPV
- MenACWY
UK vaccination summary: Adults
- Pneumococcal
- Influenza
- Shingles
UK vaccination summary: Pregnant women
- Influenza (during flu season)
- Pertussis (whooping cough) from 16 wks
Diphtheria: Definition
Diphtheria is caused by the Gram positive bacterium Corynebacterium diphtheriae
Pathophysiology
- releases an exotoxin encoded by a β-prophage
- exotoxin inhibits protein synthesis by catalyzing ADP-ribosylation of elongation factor EF-2
Diphtheria toxin commonly causes a ‘diphtheric membrane’ on tonsils caused by necrotic mucosal cells. Systemic distribution may produce necrosis of myocardial, neural and renal tissue
Possible presentations
- recent visitors to Eastern Europe/Russia/Asia
- sore throat with a ‘diphtheric membrane’ - see above
- bulky cervical lymphadenopathy
- neuritis e.g. cranial nerves
- heart block
Tetanus: Definition
Tetanus is caused by the tetanospasmin exotoxin released from Clostridium tetani. Tetanus spores are present in soil and may be introduced into the body from a wound, which is often unnoticed. Tetanospasmin prevents release of GABA
Features
- prodrome fever, lethargy, headache
- trismus (lockjaw)
- risus sardonicus
- opisthotonus (arched back, hyperextended neck)
- spasms (e.g. dysphagia)
Management
- supportive therapy including ventilatory support and muscle relaxants
- intramuscular human tetanus immunoglobulin for high-risk wounds (e.g. compound fractures, delayed surgical intervention, significant degree of devitalised tissue)
- metronidazole is now preferred to benzylpenicillin as the antibiotic of choice
Pertussis (whooping cough): Definition
Overview
- caused by the Gram-negative bacterium Bordetella pertussis
- incubation period = 10-14 days
Features, 2-3 days of coryza precede onset of:
- coughing bouts: usually worse at night and after feeding, may be ended by vomiting & associated central cyanosis
- inspiratory whoop: not always present (caused by forced inspiration against a closed glottis)
- infants may have spells of apnoea
- persistent coughing may cause subconjunctival
- haemorrhages or even anoxia leading to syncope & seizures
- symptoms may last 10-14 weeks* and tend to be more severe in infants
- marked lymphocytosis
Polio: Definition
Polio, short for poliomyelitis, or infantile paralysis, is an infectious disease caused by the poliovirus. In about 0.5 percent of cases, there is muscle weakness resulting in an inability to move.
Haemophilus influenzae B (Hib): Definition
Haemophilus influenzae type b (Hib) Haemophilus influenza type b (Hib) is a bacteria responsible for severe pneumonia, meningitis and other invasive diseases almost exclusively in children aged less than 5 years. It is transmitted through the respiratory tract from infected to susceptible individuals.
Hepatitis B: Definition
Hepatitis B is a double-stranded DNA hepadnavirus and is spread through exposure to infected blood or body fluids, including vertical transmission from mother to child. The incubation period is 6-20 weeks.
The features of hepatitis B include fever, jaundice and elevated liver transaminases.
Pneumococcal: Definition
Pneumococcal infections are caused by the bacterium Streptococcus pneumoniae and can lead to pneumonia, septicaemia (a kind of blood poisoning) and meningitis.
Rotavirus: Definition
Rotavirus is a genus of double-stranded RNA viruses in the family Reoviridae. Rotaviruses are the most common cause of diarrhoeal disease among infants and young children.
Most children recover at home within a few days, but nearly 1 in 5 will need to see their doctor, and 1 in 10 of these end up in hospital as a result of complications such as extreme dehydration.
Since its introduction into the vaccination programme, the rotavirus vaccine has prevented more than 70% of cases.
MenB
Meningococcal B
The word “Men” is an abbreviation for the word meningococcal, not meningitis as is often mistaken. Meningitis and meningococcal are not exactly the same.
Meningitis is the inflammation of the membranes that surround and protect the brain and spinal cord. Meningococcal refers to a type of bacteria that can cause meningitis. There are different groups of meningococcal bacteria, for example meningococcal group B which is commonly abbreviated to MenB (other groups include MenA, MenC, MenW and MenY).