Pharmacovigilance is the science and activities relating to the detection, assessment, understanding, response and prevention of adverse drug reactions (ADRs)Adverse drug reaction (ADR)A response to a drug that is noxious and unintended and occurs at doses normally used in man for the prophylaxis, diagnosis or therapy of disease, or for modification of physiological function. and other potential medicine-related problems – including adverse events following immunizationAdverse event following immunization (AEFI)Any untoward medical occurrence which follows immunization and which does not necessarily have a causal relationship with the usage of the vaccine. The adverse event may be any unfavourable or unintended sign, abnormal laboratory finding, symptom or disease..
The specific aims of pharmacovigilance are to:46
- Improve patient care and safety in relation to the use of medicinesDrug (or medicine)Any substance in a pharmaceutical product that is used to modify or exploit physiological systems or pathological states for the benefit of the recipient. The term drug/medicinal product is used in a wider sense to include the whole formulated and registered product, including the presentation and packaging, and the accompanying information. Vaccines are drugs/medicines. in medical and paramedical interventions, including vaccination,
- Improve public health and safety in relation to the use of all medicines,
- Contribute to the assessment of benefit, harm, effectivenessVaccine effectivenessThe probability that a vaccine, when used in the field under routine vaccination circumstances, confers immunity in a population. Expressed as a percent. and risk of medicines,
- Encourage the safe, rational and effective (including cost-effectiveCost-effectiveThis refers to a type of economic analysis that allows comparison of different intervention options by estimating the cost per health outcome for each alternative intervention. It indicates which interventions provide the greatest impact for a given cost.) use of medicines,
- Promote understanding, education and clinical training in pharmacovigilance and effective communication of its surveillance role to the public.
Origins of pharmacovigilance
The WHO Programme for International Drug Monitoring (PIDM) was established in 1968 in response to the thalidomide disaster in which thousands of infants were born with congenitalCongenitalA condition that is present at birth, though not necessarily hereditary. deformations following fetal exposure to thalidomide, a medicine that had been used to treat morning sickness in pregnancy.
The PIDM, now coordinated through the Uppsala Monitoring Center (UMC) in Sweden, developed an international system for detecting previously unknown or poorly understood adverse drug reactions (ADRs)Adverse drug reaction (ADR)A response to a drug that is noxious and unintended and occurs at doses normally used in man for the prophylaxis, diagnosis or therapy of disease, or for modification of physiological function.. National regulatory authorities (NRAs) are responsible for reporting ADRs, particularly rare ones or new signalsSignalReported information on a possible causal relationship between an adverse event and a drug, the relationship being previously unknown or incompletely documented. Usually more than a single report is required to generate a signal, depending upon the seriousness of the event and the quality of the information., to the UMC so that they can be monitored within the global population.46
In many countries, National pharmacovigilance centresNational pharmacovigilance centreA governmentally recognized centre (or integrated system) within a country with the clinical and scientific expertise to collect, collate, analyse, and give advice on all information related to drug safety. are established or existing entities are designated to serve this function on behalf of the NRA. Such centres collect information about AEFI using standardized methodologies. They analyse this information and communicate regularly with NRAs to update the safety profilesSafety profileA summary of the evidence on the safety of a medical product, such as a vaccine or drug, under ideal conditions of use, including the incidence of any adverse reactions relative to the number of doses given. of the products used in a country. You will learn more about vaccine safety institutions and reporting mechanisms in Module 5.