Information about vaccine safety comes from several sources:

• Vaccine manufacturers;
• Information published in scientific studies; 
• Databases that collect information about disease and causes of deaths; 
• Systems that collect reports of adverse drug reactions. In the UK this is called the Yellow Card Scheme; and 
• International regulatory agencies.

When the MHRA approves a vaccine it also issues guidance for health professionals on its use. This includes details of extra measures that need to be put in place to protect patient safety. 

The Yellow Card Scheme

দ্য Yellow Card Scheme collects and monitors information on safety concerns about medicines, medical devices and e-cigarettes. This includes all adverse events as well as concerns related to product quality or counterfeit products.

It relies on voluntary reporting by health professionals and patients when events occur. There is a dedicated page for COVID-19 vaccines and treatments with an online reporting tool. Adverse events can also be reported using the Yellow Card App. The system acts as a real-time early warning system, as reports will highlight areas of concern that require investigation.

Yellow card reports are then combined with information from other data sources so that medicine safety experts can assess the risks and benefits for each product. Having databases like this, and other data resources that can be linked, are important research tools. For vaccine safety monitoring, data from electronic health records are a particularly valuable research resource.

As more countries roll out COVID-19 immunisation programmes, more data about overall safety and any adverse events will accumulate.