About Active Surveillance System for Adverse Reactions to Medicines and Vaccines (ASAR)

The national spontaneous adverse event (AE) monitoring programme by the Vigilance and Compliance Branch (VCB) of Health Sciences Authority of Singapore (HSA) ensures that health products used in Singapore are safe. To enhance the AE monitoring programme, Synapxe and HSA have developed an Active Surveillance System for Adverse Reactions to Medicines and Vaccines (ASAR) to detect and validate safety signals.

ASAR is the first nation-wide application that analyses structured healthcare data and unstructured clinical notes from all public acute hospitals to detect and validate drug safety signals to protect public health in Singapore.

New approach of active surveillance

First nation-wide application that analyses such data

Programmed to pool > 2 million de-identified records daily

Six modules built to facilitate safety analysis


ASAR at a glance


COVID-19 vaccination is a critical tool to control the spread of the infection and to enable resumption of pre-pandemic life. As COVID-19 vaccines are developed under compressed timelines with much shorter safety experience pre-approval compared to conventional vaccines, an enhanced safety monitoring programme is needed to promptly detect and address any emerging safety concerns to maintain public trust in the deployed vaccines.


The back-end engine of ASAR pools more than two million de-identified structured and unstructured records from multiple sources daily.

The front-end application helps HSA analysts facilitate data analysis, signal detection, signal validation and benefit-risk assessment of medicines and vaccines. 

The AI-powered deep-learning drug-AE detection algorithm allows HSA officers to screen for potential associations between medicines/vaccines and AEs.


The capacity to develop algorithms and tools for near-real time   monitoring of COVID-19 vaccines is crucial to facilitate appropriate regulatory decisions. HSA was able to provide timely and relevant safety assessments of COVID-19 vaccines to MOH policymakers for making decisions on Singapore's COVID-19 vaccination strategy.

Future Outlook

HSA and Synapxe will continue to refine and strengthen ASAR to enhance the AE monitoring programme and in preparation for impending Disease X.

Moving forward, the system’s infrastructure, technology, and operations will be continuously enhanced. This enables HSA to tap on real world data to detect and quantify the risk of AEs and determine the overall benefit-risk balance of medicines and vaccines used in Singapore to ensure public safety.




By continuing to use and navigate this website, you consent to the use of cookies in accordance with our Privacy Policy.