How international pharmacovigilance systems monitor vaccine safety across borders
Vaccine safety monitoring is a global effort. While each country maintains its own surveillance systems, international coordination is essential for detecting signals that cross borders, sharing data across healthcare systems, and ensuring consistent regulatory responses to emerging safety concerns.
This section covers the major international pharmacovigilance systems — how they work, what data they collect, their strengths and limitations, and how they complement national systems like VAERS.
Some adverse events are too rare to detect in any single country's data. When multiple countries report similar patterns simultaneously, the combined signal becomes statistically meaningful. Global coordination enables detection that national systems alone cannot achieve.
Global systems enable regulatory agencies to share findings, coordinate label updates, and issue consistent safety guidance. When EMA restricts a vaccine, WHO can rapidly communicate that decision to member states worldwide.
International databases use standardised terminology (MedDRA) and case definitions (Brighton Collaboration) to ensure reports from different countries are comparable. Without standardisation, cross-national analysis would be unreliable.
The World Health Organization coordinates global adverse event following immunization surveillance, feeding into the VigiBase global database managed by the Uppsala Monitoring Centre.
The world's largest pharmacovigilance database, managed by the Uppsala Monitoring Centre in Sweden. Contains over 30 million adverse event reports from more than 170 countries.
The European Medicines Agency's centralized database for adverse drug reactions across all EU member states. Enables Europe-wide signal detection and coordinated regulatory response.
The UK MHRA voluntary reporting scheme for adverse drug reactions including vaccines. Data is publicly searchable and regularly published in drug safety updates.
WHO. "Global Vaccine Safety Initiative." World Health Organization. https://www.who.int/vaccine_safety/initiative/en/
Uppsala Monitoring Centre. "VigiBase." WHO Collaborating Centre for International Drug Monitoring. https://www.who-umc.org/vigibase/vigibase/
EMA. "EudraVigilance." European Medicines Agency. https://www.ema.europa.eu/en/human-regulatory/overview/pharmacovigilance/eudravigilance
UK MHRA. "Yellow Card Scheme." Medicines and Healthcare products Regulatory Agency. https://yellowcard.mhra.gov.uk