20 Questions
What is one of the basic principles of bioethics related to vaccination safety?
Primum non nocere
What is the significance of the phrase 'Primum non nocere' in relation to vaccination safety?
It emphasizes the importance of minimizing harm in medical interventions
What does a temporal association between vaccination and adverse events not prove?
Coincidence vs causality
What is an example of a type III hypersensitivity reaction mentioned in the text?
Local inflammation and swelling / Arthus reaction
What can cause antibody-dependent enhancement (ADE) according to the text?
Excipients in vaccine proteins
What are the potential consequences of using incorrect diluent for lyophilized vaccines?
Respiratory arrest and death
What is a possible cause of vaccine-derived polio virus (VDPV)?
Genetic modification of the vaccine strain
What is an example of a type III hypersensitivity reaction mentioned in the text?
arthus reaction
What are examples of pre-existing host factors that influence risk for adverse events?
Age, sex, preceding vaccine doses, skin color, pre-excisting hypersensitivity, immune deficiency, genetic factors
Explain how can side effects of vaccine have very strong consequences on vaccination program
If people start vaccinating themselves the prevalence of disease decreases. The more people are vaccinated the more chances for different adverse effects. If people get too scared and dont vaccinate it can cause an outbreak of the disease again and the erradication will take longer time
What are the 4 types of side effects mansion at least 2 from each
immediate onset- general, anaphylactics Late onset vary Local- rash, pain, swelling Systemic- fever chills fatigue
what can be a reason for a delayed cutaneus reaction?
Delayed type or T cell mediated hyper sensitivity reaction
Describe Type 1 hypersensitivity
Type I is immediate hypersensitivity IgE antibodies bind to FceR1 receptor on mast cells and basophils. Crossling of IgE induces degranulation
Describe Type II hypersensitivity
Type II is cytotoxic hyoersensitivity. IgG antibodies bind to cell surface antigen causing cell damage by complement activation or by cytotoxic T cells.
Describe Type III hypersensitivity
Type III- immune complex reaction antigen- antibody immune complexes deposit in tissue with subsequent complement fixation and neutrophil aggregation.
Describe type IV
Its called delayed hypersensitivity Cytokines secreted by TH1 cells activate macrophages and cytotoxic T cells
name two ex of known side effects and their vaccine
Rash- MMR Tetanus- arthus reaction
Name mechanisms of VAED
- Antibody-dependent enhancement- occurs when antibodies increase the ability of a vrius to infect cells
- Antibody enhanced disease- occurs when antibodies exacerbate inflammation
- Th2 mediated pathology- ( assosiated with eosinophil infiltration)
- responses to cellular debris or other contaminants in vaccine formulation -
Name 6 pathogenesis of ae by vaccination?
- administraion process
- contamination
- replication of the vaccine antigen
- direct effect of a vaccine component
- Immune response to a vaccine componnt
- Unknown
what are some vaccine related factors that can influence the risk
vaccine type, strain, attenuation, dose
Study Notes
- Vaccines have led to the successful prevention and eradication of several infectious diseases, such as smallpox and polio, with significant reduction in cases and deaths for others like pertussis, measles, and rubella.
- However, vaccine confidence can be influenced by adverse events, which can range from minor reactions like fever, pain, and redness at the injection site to more severe ones like anaphylaxis, allergic reactions, and neurological disorders.
- Side effects of vaccines can jeopardize vaccination programs, leading to decreased coverage and potential resurgence of diseases.
- For example, in the case of pertussis vaccination in the USA, the number of cases and deaths decreased significantly after the start of vaccination in the 1940s, but side effects of the whole cell pertussis vaccine (Pw) led to loss of confidence and a resurgence of the disease in the late 1980s and 1990s.
- Vaccine side effects can be immediate (hours to days) or delayed (days to weeks), and can be local or systemic in nature. Some common local reactions include pain, swelling, redness, while systemic reactions can include fever, chills, fatigue, headache, and myalgia.
- Immediate type hypersensitivity reactions (type I), such as anaphylaxis, can be life-threatening and require immediate medical attention. These reactions are rare, occurring in less than 1:1 000 000 vaccine doses, and can be caused by excipients as well as vaccine proteins.
- Type III hypersensitivity reactions, such as Arthus reactions, can cause local inflammation and swelling, and can occur after vaccination with tetanus and diphtheria toxoid.
- Type IV hypersensitivity reactions, such as delayed cutaneous reactions, can occur after vaccination with BCG and mRNA vaccines.
- Vaccine-associated enhanced disease (VAED) can occur due to antibody-dependent enhancement (ADE), antibody-enhanced disease (AED), Th2-skewed responses, or components of vaccine formulations.
- ADE occurs when antibodies increase the ability of a virus to infect cells, while AED occurs when antibodies exacerbate inflammation. Th2-skewed responses can be pathogenic for some infections, and components of vaccine formulations can mediate pathogenic cellular responses when encountered again as contaminants in the challenge material.
- It is important to evaluate vaccine safety through rigorous testing and monitoring, as well as addressing vaccine criticism, hesitancy, and refusal.
- Examples of vaccine-associated side effects include pustule formation and scarring with cowpox vaccine, lymphadenitis with BCG, vaccine-associated paralytic polio (VAPP) with OPV, intussusception with rotavirus vaccine, and meningitis with mumps vaccine.
- Mechanisms of vaccine-associated enhanced disease include antibody-dependent enhancement, antibody-enhanced disease, Th2-skewed responses, and components of vaccine formulations.
- Examples of vaccines associated with enhanced disease include the formol inactivated RSV vaccine and the dengue infection.
- It is important to recognize and treat vaccine-induced adverse reactions, such as anaphylaxis, and to ensure appropriate vaccine preparation and administration to minimize the risk of vaccine-associated side effects.
Test your knowledge on vaccine safety, pharmacovigilance, and the process of evaluating potential side effects of vaccines throughout their development. Explore the importance of monitoring vaccine safety data at both national and international levels.
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