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Slide 7 - Monitoring vaccine safety Routine testing before release. As most vaccines are given to healthy individuals (mostly children) in order to prevent disease, extremely high standards of safety are needed. Each batch of vaccine goes through: Extensive quality control and safety testing during the manufacturing process Manufacturers must submit samples of each batch and results of their own potency, safety and purity tests for independent assessment before release into general use. Phase lV studies - Post-licensing monitoring of vaccines and vaccination programmes. When a vaccine is in general use, post-licensing monitoring continues to: Detect rare or new reactions not apparent in clinical trials Measures the effect of the programme on target diseases by: monitoring vaccine coverage surveillance of infectious disease through routine reports or special surveys. Yellow card scheme In the UK the Medicine and Healthcare products Regulatory Agency (MHRA) and the Committee on Safety of Medicines (CSM) monitor the safety of all medicines by the Yellow card system. Doctors, dentists, pharmacists, nurses and coroners are required to report all suspected reactions, which may be linked to a vaccine. Studies of vaccine safety. Information on safety is also collected from clinical trials and safety studies of marketed medicines, epidemiological studies and surveys, disease and death registries, regular safety updates supplied by pharmaceutical companies, the information from other regulatory authorities and published literature. Cohort studies. These compare groups of children who have had the vaccine with a similar group of children except that they have not had the vaccine, measuring the frequency of adverse events, such as fits, in both groups. The true frequency of these events, and therefore the risk figures, can then be worked out. Case-control study. This method is better for investigating rare events. Most vaccines are given to children in the first two years of life when problems such as delayed development, convulsions, autism and cerebral palsy are newly recognised and diagnosed. Vaccination histories of vaccination are taken from patients with a specific condition that is possibly related to vaccination. These are compared with a control group who do not have the condition, but are of a similar age and the same sex. Record linkage. Widespread use of computers can link hospital admission records with immunisation records. This methodology can: Estimate the chance of an adverse event following an immunisation (absolute) Estimate the risk of an adverse event which is due to the vaccine (attributable risk) rather than to some other factor. This method will form the basis of a new national system for routinely monitoring vaccine safety. Reference Childhood Immunisation The Facts. (2001) Bedford H, Elliman D. Health Promotion England, London

Slide 8 - Contraindications A contraindication is a condition in a recipient that greatly increases the chance of serious adverse reaction. For example, administering influenza vaccines to individuals with a true anaphylactic allergy to egg. The only permanent contraindications to any vaccines are defined in Immunisation against Infectious Disease (1996), page 20-21, paragraphs 7.2-7.3 Severe local reactions to a preceding dose Severe systemic reaction to a preceding dose Anaphylactic reaction to any component of a vaccine Generally at least one dose must have been administered before further doses are withheld. A growing body of knowledge and experience shows vaccines can be safely given in the presence of past or present contraindications, e.g. anaphylactic reaction to egg is no longer a contraindication to MMR vaccine. Contraindications to live vaccines In cases of immunosuppression by treatment the decision to withhold vaccines should be temporary. This decision is made for live vaccines because of the risk of developing the actual disease the vaccines are designed to prevent, e.g. disseminated infections with BCG or paralytic polio from live polio vaccine. Every attempt should be made to immunise such individuals when immune function is restored – between 3 months (high dose corticosteroids) and 6 months (chemo- or radiotherapy). Precautions are defined as any condition in a recipient that: May increase the chance of a serious adverse reaction, e.g. previous local or systemic reaction to a preceding dose May compromise the ability of the vaccine to produce immunity, for example inactivated vaccines in immunocompromised individuals Where the benefit of protection from a vaccine outweighs the perceived potential harm from the vaccine, e.g. in a pertussis epidemic, the decision may be to vaccinate and treat the adverse reaction if it occurs. Immunising a child that is suffering an acute illness with fever will not make the child any sicker. This is to avoid wrongly associating any cause of fever or its progression with the vaccine and to avoid increasing any pre-existing fever. Reference: Epidemiology and Prevention of /vaccine-preventable Diseases. (2003) Atkinson W, Wolfe C (Eds). Department of Health and Human Sciences Centers for Disease Control and Prevention, Atlanta

Slide 9 - Adverse reactions Vaccines are mainly given to the childhood population, starting routinely in very young babies at two months of age. Although vaccines are amongst the safest of all medicines, there is still a risk of adverse events or side effects. There is a statutory requirement for pharmaceutical companies to report serious adverse reactions to their products on a world-wide basis as a further safety check that children are not put at risk. Definition … “An untoward effect caused by a vaccine that is extraneous to the vaccine’s purpose of production of immunity.” A vaccine adverse event refers to any adverse event that occurs following immunisation: it could be a true adverse event just coincidental with further research needed to distinguish between them. Local reactions: Local reactions are relatively common with inactivated vaccines (DTP-Hib) Pain, redness and swelling at the injection site usually mild and self limiting Systemic: Fever, malaise, headache May be unrelated to the vaccine Live attenuated vaccines Antigens must replicate to produce immunity Mimic the diseases they protect against Symptoms occur after an incubation time, usually 7-21 days Allergic Due to the vaccine or vaccine component Very rare Risk can be minimised by screening Real versus myth Coincidences between two events, e.g. vaccination and getting a disease, may suggest cause and effect. Event A happening before event B doesn’t mean they are related, e.g. MMR is commonly given at 13 months of age, and 13 months is the average age a child starts walking - therefore MMR causes walking! Chance alone may appear to link events, e.g. the suggestion of a link between MMR and autism. As diseases disappear, the balance of risk shifts and the risk of adverse events appears to increase This gives rise to an increase of mythical adverse events, e.g. hair loss or autism. Reference: Epidemiology and Prevention of /vaccine-preventable Diseases. (2003) Atkinson W, Wolfe C (Eds). Department of Health and Human Sciences Centres for Disease Control and Prevention, Atlanta

Slide 10 - Benefits and risks Every human activity has risk attached to it. Parents listen to and act on science-based advice to protect their children, e.g. putting babies to sleep on their backs to decrease the risk of cot death. The law sometimes supports behaviour changes, e.g. seat belts and baby seats in cars. But despite these measures, there are still incidents of serious injury or death in road traffic accidents. A successful immunisation programme means that certain diseases disappear, e.g. polio. Previously serious diseases become preventable with the development of new vaccines, e.g. meningococcal C disease. But as the incidence of a disease decreases, it may appear that the risks from adverse reactions from the vaccine outweigh the risk of the actual disease or it’s complications. These fears have been around since 1796 when Edward Jenner discovered that inoculating individuals with cow-pox protected them against the far more deadly smallpox. In modern society, the advent of so-called investigative journalism and the Internet has ensured these fears live on and continue to fuel the anti-vaccination lobby.

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