Immunisation and Medication 2024 PDF

IMMUNISATION Dr Jaco Joubert & Haematologist Dept of Haematology and Cell Biology MEDICATION T: 051 401 9111 in...

IMMUNISATION Dr Jaco Joubert & Haematologist Dept of Haematology and Cell Biology MEDICATION T: 051 401 9111 [email protected] www.ufs.ac.za  CONTENT PART 1: Immunisation Definitions: immunisation, adjuvant, hapten, toxoid National immunisation schedule PART 2: Medication Corticosteroids Non-steroidal anti-inflammatory drugs Antihistamines T: 051 401 9111 [email protected] www.ufs.ac.za  WHAT IS IMMUNISATION? “Immunisation is the process whereby a person is made immune or resistant to an infectious disease.” www.who.int/topics/immunization/en/  Immunisation Passive Active Natural Natural (e.g. maternal (e.g. natural infection antibodies protecting such as measles) infant) Artificial Artificial (e.g. administration of (e.g. administration of tetanus antitoxin) tetanus toxoid) PASSIVE IMMUNITY Transfer of antibody directed at specific infective agent Recipient’s immune system is not stimulated Acts immediately Short lived Individual at risk Individual possessing antibody to infective agent in question PASSIVE IMMUNISATION EXAMPLES Natural mechanisms Transplacental transfer of antibodies (IgG) Breastfeeding (transfer of especially IgA) Artificial mechanisms Antitoxin (antibody) administration Gammaglobulin therapy – An individual in contact with an infectious disease and no time for an immune response to active vaccine – Immunosupressed patient at risk of contracting a disease which is endemic – No preparation available for active vaccination ACTIVE IMMUNITY Results from stimulation of person’s own immune response Considerable delay before protection Immunity long lived (may last a lifetime) ACTIVE IMMUNISATION Live attenuated vaccine – Natural live organisms manipulated artificially and rendered harmless, but still viable (alive) – Induce excellent immunity with durable protection Inactivated (“dead”) vaccine – Organism, or parts of organism, capable of eliciting an immune response, but not capable of causing infection – Split or whole virus preparations – Antigenic proteins made by recombinant DNA technology – Require course of 2-3 injections and boosters – Most require an adjuvant LIVE ATTENUATED VACCINE INACTIVATED VACCINE ADJUVANTS Any substance that acts to accelerate, prolong or enhance antigen-specific immune responses when used in combination with specific vaccine antigens Many inactivated vaccines, particularly the recombinant proteins, require an adjuvant Often adsorbed onto aluminium hydroxide or a carrier protein Other examples: – Virosomes – Organic compounds (e.g. squalene, mineral oil) – Etc. HAPTEN Molecule that is too small to be immunogenic on its own, but after conjugation to a carrier protein becomes immunogenic, resulting in the production of antibodies. Example: – Certain drugs, when bound to the red cell membrane, cause an immune reaction with resultant destruction of the drug-red cell complex by antibodies (autoimmune haemolysis). TOXOID Bacterial toxin (usually an exotoxin) Toxicity has been inactivated or suppressed either by chemical (formalin) or heat treatment Immunogenicity is however maintained Thus, when used during vaccination, an immune response is mounted and immunological memory is formed against toxoid, without resulting in toxin-induced illness  VACCINE EXAMPLES Live attenuated Inactivated Toxoid Small pox Pertussis Measles Cholera Mumps Hepatitis A,B Rubella Haemophilus Diphtheria influenzae Varicella Tetanus Polio (parenteral) Poliomyelitis (oral) Pertussis Influenza Yellow fever Rabies BCG Meningococcal, Rotavirus pneumococcal NEXT GENERATION VACCINES: COVID-19 Protein Vector mRNA subunit vaccine vaccine vaccine Janssen/Johnson Pfizer-BioNTech & Johnson Novavax AstraZeneca and Moderna University of Oxford PROTEIN SUBUNIT VACCINE MESSENGER RNA (MRNA) VACCINE VECTOR VACCINE SPECIAL POINTS TO CONSIDER A. Pregnancy Live attenuated vaccines should preferably not be administered: potential harm to fetus Woman immunised with live attenuated vaccine should preferably not become pregnant within next 4 weeks Inactivated vaccines cannot infect fetus, but... Avoid vaccines known to commonly cause systemic reactions, which may harm fetus B. Immunoglobulin or blood products Will prevent fully effective immunisation for at least 3 months Wait 2 weeks after vaccination with live vaccine before administering immunoglobulin SPECIAL POINTS TO CONSIDER C. Febrile illness Postpone vaccination in acutely ill, severely febrile patients Presence of mild infection is not a contraindication in healthy subjects D. Traces of antibiotics Found in some vaccines (e.g. neomycin, polymyxin) History of systemic hypersensitivity (not just contact dermatitis) is a contraindication SPECIAL POINTS TO CONSIDER E. Immunosuppression Inactivated vaccines generally safe Asymptomatic HIV-infected children: should be routinely immunised (exception: BCG) Oral polio vaccine (live attenuated) can be given when deficient cellular immunity (e.g. HIV) is present, but use inactivated polio vaccine in cases of severe humoral immunodeficiency Varicella vaccine may be given in presence of isolated B-cell deficiency Leukaemia/lymphoma: rather seek expert advice Chemotherapy/high dose corticosteroids: no live vaccines SPECIAL POINTS TO CONSIDER F. Concurrent administration Infants are naturally exposed to multiple antigens simultaneously while growing up No evidence to suggest safety and efficacy problems when multiple antigens are administered simultaneously Different injectable vaccines should ALWAYS be administered at different injection sites (see immunisation schedule) Be careful not to contaminate other vaccines or vaccine equipment with BCG: can lead to slowly developing granulomatous abscess Do not mix vaccines with other vaccines or products in the same syringe SPECIAL POINTS TO CONSIDER G. Bleeding disorders In case of thrombocytopenia, bleeding disorders (e.g. haemophilia), or anticoagulant therapy, vaccine should be administered subcutaneously (or intramuscularly only with caution) H. Biological variation Vaccines are biological substances and will elicit different responses in different people No vaccine will protect 100% of recipients CONTRAINDICATIONS TO VACCINATION History of: Serious reaction (e.g. anaphylaxis) Encephalopathy Guillain-Barre syndrome within six weeks of previous dose of tetanus toxoid Temp ≥ 40.5 °C within 48 hours of vaccination, not due to other causes Collapse/shock-like state within 48 hours of vaccination Persistent, inconsolable crying lasting > 3hours, occurring 2 weeks Developments of cataracts – Associated with long term steroid use Other: ptosis, midriasis, conjunctival petechiae, etc. SYSTEMIC CORTICOSTEROIDS SIDE EFFECTS PROSTAGLANDIN AND INFLAMMATION With injury, damaged tissues release chemicals called prostaglandins. Prostaglandin production is facilitated by cyclooxygenase enzymes (COX-1 and COX-2). Functions of prostaglandin: – Necessary for wound healing, – Promotes inflammation (including pain and fever), COX-1 & -2 – Plays a role in platelet activation, and – Protects the stomach lining from stomach acid. COX-1 NON-STEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS) Mechanism of action: ↓ ↓ NSAIDs block COX enzymes Prostaglandin Inflammation, synthesis pain and fever *The effect of prostaglandins on platelets and the stomach lining is also inhibited: Reduced platelet function Stomach ulcers  NSAIDS CLASSIFICATION Non-selective COX Inhibit both COX-1 & COX-2 enzymes inhibitors Aspirin (Disprin®); Ibuprofen (Brufen®) Inhibit both COX enzymes, but preferentially Preferential COX-2 COX-2 inhibitors Meloxicam (Mobic®) Selective COX-2 Only inhibit COX-2 inhibitors Celecoxib (Celebrex®) Complex mode of action. Also inhibits COX Analgesic- enzymes. antipyretics Paracetamol (Panado®) OPHTHALMIC NSAIDS Indications: – Peri-operative setting (minimise miosis and inflammation) – Mild superficial inflammatory conditions (e.g. episcleritis) Usually given in the form of eye drops. Examples: – Diclofenac (Voltaren Ophtha®) – Flurbiprofen (Ocufen Liquifilm®) – Ketorolac (Acular®) Side effects in the eye: – Redness – Burning – Pain, discomfort – Itching  ANTIHISTAMINE DRUGS Used to alleviate the symptoms associated with allergic reactions. Other uses: – Sedation – Motion sickness (antiemetic) Mechanism of action – binds to histamine receptor and inactivates it. First generation antihistamines – Crosses into the brain, causing sedation as a side effect – Examples: chlorpheniramine (Allergex®), promethazine (Phenergan®) Second generation antihistamines – No sedation – Examples: desloratadine (Deselex®), cetirizine (Zyrtec®) OPHTHALMIC ANTIHISTAMINES Indications: – Allergic conjunctivitis – Mild superficial inflammatory conditions (e.g. episcleritis) Often used in combination with sympatomimetics. Examples: – Antazoline (in Safyr Bleu ®, Spersallerg ®) Side effects: – Local stinging (transient) QUESTIONS OR COMMENTS? T: 051 401 9111 [email protected] www.ufs.ac.za