Immunisation 8122MED PDF

Immunisation Dr Emma Gale Public Health Physician/Senior Lecturer Acknowledgement of country  Define what immunisation is Describe the different types of vaccines Define and describe the cold-chain Learning Explain what Adverse Events Following...

Immunisation Dr Emma Gale Public Health Physician/Senior Lecturer Acknowledgement of country  Define what immunisation is Describe the different types of vaccines Define and describe the cold-chain Learning Explain what Adverse Events Following Immunisation (AEFIs) are objectives Explain the principles of management of AEFIs *Focus on the principles and where you can find information* Vaccine success - Smallpox Old disease that influenced history 20-45% mortality for variola major strain Edward Jenner first vaccine 1796 (although inoculation practiced well before this in Asia innoculate with cowpox and Africa) Eradication declared May 8, 1980 Image from: Berche, P. (2022). Life and death of smallpox. Presse Med, 51(3), 104117. doi:10.1016/j.lpm.2022.104117  Vaccine Success – Measles in Australia 1989 - one dose added measles free since 2014 still some come in internationally Image from: Australian Institute of Health and Welfare. (2018). Measles in Australia. AIHW. https://www.aihw.gov.au/getmedia/c828baef-75d9-4295-9cc9-b3d50d7153a2/aihw-phe-236_measles.pdf.aspx%E2%80%8B What is Immunisation? ‘’Immunisation is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine.’’ -WHO  Versus vaccination? Vaccination = The process of getting a vaccine to stimulate immunity Vaccine = A biological preparation that can stimulate the immune system to produce antibodies against a disease  Active versus Passive Immunisation Active immunisation Uses a vaccine to stimulate a person’s own immune system to develop antibodies to an infection Passive immunisation Direct transfer of antibodies to a non-immune person for temporary protection Human rabies immunoglobulin (animal bites) Zoster immunoglobulin (for susceptible at-risk people following exposure to varicella)  Vaccine development and safety A vaccine needs to go through several phases of clinical trials before it can be licensed Pre-clinical assessment where vaccine safety and efficacy are tested in lab and animal models Phase I clinical trials a small number of healthy participants are recruited to test vaccine dosage and safety Phase II clinical trials involve hundreds of participants to test immunogenicity (ability to invoke an immune response) and safety Phase III clinical trials involve thousands of participants to test safety and efficacy (disease prevention) Regulatory bodies assess the safety and effectiveness before a vaccine is licensed – Therapeutic Goods Administration Phase IV involves ongoing monitoring of vaccine safety following licensure intussception from increased use of rotavirus vaccine Figure: National Centre for Immunisation Research and Surveillance. (2022). Phases of clinical trials. NCIRS. https://ncirs.org.au/phases-clinical-trials years-long process Vaccine Components stimulate immune response  to vaccine form memory cells destroy pathogen deactivate or take component Active Component Type How it works Example vaccines Live-attenuated Weakened version of the pathogen Measles-mumps-rubella, *Not be given to people with weakened immune systems Varicella (chickenpox) long-term protection Inactivated Inactivated version of the pathogen (split or killed) Hepatitis A, Q Fever or killed via chemical or heat Protein subunit Contain isolated proteins (bits) from pathogens to stimulate Hepatitis B immune response subunit to immune response Polysaccharide and conjugated Use polysaccharides (sugars) from the outside of some bacteria Haemophilus influenzae B, to stimulate immune response; sometimes attached Meningococcal ACWY (conjugated) to another protein to improve immune response Toxoid Weakened versions of the toxins produced by certain bacteria Diphtheria, Tetanus Viral vector Harmless viral vector carries genetic code for proteins from a AstraZeneca COVID-19 pathogen, resulting in the production of these proteins to stimulate immune response genetic codes for immune response Nucleic acid based Use genetic material (RNA or DNA) from the pathogen that Pfizer and Moderna COVID- provide instructions for the body to make antigens that then 19 stimulate an immune response  Vaccine Additives ADJUVANTS – enhance the immune response – aluminium saltsDTP vaccine stronger response STABILISERS – keep components stable during storage – lactose, sucrose, amino acids, Gelatin PRESERVATIVES – aromatic alcohols, thiomersal ANTIBIOTICS – sometimes used during manufacturing SURFACTANTS/EMULSIFIERS – sorbitol soap and shampoo DILUENTS – used to dilute the vaccine prior to administration – sterile water or saline How long does immunity last after a vaccine? That depends Protection kicks in around 7-14 days after vaccination Immunity wanes over time – many vaccines need boosters (tetanus, pertussis) Not all disease strains/types covered by a vaccine Seasonal influenza – different every year Meningococcal ACWY versus B vaccine  Cold Chain The cold chain is a system of transporting and storing vaccines within the safe temperature range +2 to +8 degrees Celsius “Strive for 5” for 5 degrees National Vaccine Storage Guidelines National Vaccine Storage Guidelines  Breaches in cold chain A cold chain breach occurs when temperatures deviate outside of the safe range Most vaccines destroyed by freezing, some are sensitive to heat Providers are to notify their local public health unit/immunisastion branch if state funded vaccines are affected Isolate affected vaccines pending discussion and decisions (not to be used) Discuss with public health unit: Prevent recurrence of cold chain breach Discuss whether vaccines need to be discarded Discuss whether revaccination of patients is required May suspend ordering if issues identified have vaccine again  Vaccination Schedule in Australia introduce Meningococcal B in 2024 some added extra - First Nations hep A provide free vaccines National Immunisation Program Schedule (health.gov.au)  know where to find Immunisation Schedule Queensland - Childhood Vaccination (health.qld.gov.au) Australian Immunisation Handbook Provides clinical advice for health professionals on how to use vaccines safely and effectively in practice By disease By vaccine Australian Immunisation Handbook who is eligible  Australian Immunisation Register National register that records vaccines given to people in Australia Automatic registration with Medicare Vaccines given through national program, school program, privately, travel  Catch up vaccination Aims to complete a person’s recommended National Immunisation Program schedule in the shortest but most effective time frame to provide optimal disease protection Need to assess person’s immunisastion status serology Can be complex Catch up calculators online via Australian Immunisation Handbook Some vaccines can’t be caught up – rotavirus vaccines have upper age limits Catch-up vaccination | The Australian Immunisation Handbook (health.gov.au)  Vaccine safety COMMON ANAPHYLAXIS VASOVAGAL Mild Medical emergency Adults and older Last 1-2 days children Usually within 15 Local pain, swelling, minutes Infants and younger redness children – think Adrenaline short timeframe anaphylaxis Headache 1.31 (95% CI, 0.90- Pain and anxiety Fatigue 1.84) per million usually trigger vaccine doses(1) 1. McNeil MM, Weintraub ES, Duffy J, et al. Risk of anaphylaxis after vaccination in children and adults. J Allergy Clin Immunol. 2016;137(3):868-878. doi:10.1016/j.jaci.2015.07.048 surveys sent reason for attendance Figure: Vaccine safety in Australia AusVaxSafety – Summary report 2022 (health.gov.au) Adverse Events Following Immunisation (AEFIs) Notifiable under the Public Health Act 2005 Any negative event following a vaccine May or may not actually be due to the vaccine The adverse event may be any: Unfavourable or unintended sign or symptom Disease Abnormal laboratory finding Monitoring AEFIs assists to: identify and better understand and safety issues with new vaccines monitor AEFI trends Identify any problems with manufacturing, storage, delivery or administration AEFI Reporting Form – Qld Health  AEFI process Notified to the Notifiable Conditions System Database (Qld) Added to Therapeutic Goods Administration (TGA) national Adverse Event Management System (AEMS) The public health unit undertake any follow up or investigation May follow up vaccine provider or patient/parent/carer Therapeutic Goods Administration may request further information to include on the national database  AEFIs – was it the vaccine? Many AEFIs have alternative explanations Coincidence versus causal relationship More likely causal if: Direct relationship – reaction at site where given soon after vaccination The event is a known potential adverse reaction for that particular vaccine The same event occurs for the same person at subsequent doses point more to vaccine itself  Vaccine Hesitancy Hesitancy is not new 1800s saw sanitary, medical, religious, scientific, political, philosophical, libertarian, ideological objections 1853 Vaccination Act ordered mandatory vaccination in England 1867 The Anti Vaccination League formed in response to penalties added to the Act fines for not vaccinating 1998 Wakefield claims MMR causes autism (it doesn't) Figure: Gillray. The Cow Pock – or the wonderful effects of the new inoculation. 1802. Available from: https://www.loc.gov/item/94509853/. 2019 Samoa measles outbreak significant plummet in vaccination 2020 COVID-19… mistrust  Effect of Wakefield’s MMR claims 1998 damage to progress Figure: McIntyre and Leask. Improving uptake of MMR vaccine in the UK. 2008. Available from: doi: https://doi.org/10.1136/bmj.39503.508484.80 30 check immunisation status for travel Addressing Vaccine Hesitancy Vaccine-hesitant people far out-number outright vaccine refusers Reasons for hesitancy can be complex, not just due to a lack of knowledge Trusted general practitioners and health staff are key Build trust Focus discussions around protecting the person and the community Address concerns Reassure regarding vaccine safety Honesty about side effects General health education goes a long way 31  Resources Ausvax summary report 2022 National Immunisation Program Schedule (health.gov.au) The Australian Immunisation Handbook | Australian Government Department of Health and Aged Care NCIRS vaccine component fact sheet Any questions please email Dr Gayatri Marwah