Adverse Drug Reaction (ADR) surveillance

ADR surveillanceADR surveillanceA surveillance system designed to collect adverse drug reactions following administration of a drug used for prophylaxis, diagnosis, or therapy of diseases, or for the alteration of a physiological process. This type of surveillance typically relies on health professionals associating an adverse reaction in an individual as a possible consequence of the drug and reporting it to the national pharmacovigilance centre, NRA or appropriate authority. is responsible for detecting and responding to adverse events associated with drugs. Although vaccines represent less than 1% of all drug products, their use and purpose is very specific and requires a modified ADR system able to detect and respond adequately and rapidly to occurring adverse events. The following pages of this module will look into why vaccines are different and what the specific needs and expectations are towards vaccine surveillance.

Post-licensure ADR surveillance is mainly conducted by national pharmacovigilance centres. In collaboration with WHO's Uppsala Monitoring Center (UMC), they have achieved a great deal in:

• Collecting and analyzing case reports of ADRs,
• Distinguishing signals from background 'noise' (or coincidental occurrences),
• Supporting regulatory decisions based on strengthened signals,
• Alerting prescribers, manufacturers and the public to new risks of ADRs.

The number of 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. participating in WHO's PIDM has increased from 10 in 1968 (when the programme started) to 108 as of June 2012.⁴² The centres vary considerably in size, resources, support structure and scope of activities. Collecting spontaneous reports of suspected ADRs remains their core activity.

The stronger the national system of pharmacovigilancePharmacovigilanceThe science and activities relating to the detection, assessment, understanding, and prevention of adverse effects or any other drug-related problem. and ADR surveillance, the more likely it is that evidence-basedEvidence-basedResearch based on systematic investigation of the outcomes of controlled interventions; the results have been verified by other researchers using the same methods. regulatory decisions will be made for the early release of new drugs with the promise of therapeutic advances. Legislation governing the regulatory process in most countries allows for conditions to be placed on approvals, such as the requirement that there should be detailed pharmacovigilance in the early years after a drug's release.

In many countries, pharmacovigilance and NRA approvals are linked by an ADR advisory committee appointed by, and directly reporting to, the NRA. An ADR committee may include independent experts in clinical medicine, epidemiologyEpidemiologyThe study of the distribution and determinants of health and disease in human populations., paediatrics, toxicology, clinical pharmacology and other disciplines. Such an arrangement inspires confidence amongst health personnel and can make a substantial contribution to public health.