Mass gatherings may have far-reaching effects on medical care because of the potential high load on the health care system. In preparation of large events (mass gatherings), such as music festivals or marathons, an extended risk assessment forms the basis for issuing advice on health and safety and possible necessary precautionary measures. In the Netherlands, the 25 regional Public Health Directors are responsible for public health and safety. This includes responsibility for advice on large-scale events, based on which the local authorities (e.g. the mayor) decide on the approval. Health care professionals are looking for better tools with regard to the arising dilemmas around responsibilities and risks. Also, as new forms of events are created, uniform (safety) regulations are lacking. GGD GHOR Netherlands (Dutch Society of the regional Public Health Services [GGD] and Major Incident Medical Planning and Coordination Offices [GHOR]) has updated the existing national guideline in collaboration with the Academic Network for Applied Public Health and Emergency Management (Anaphem). The focus was on improving the guideline by including all current expertise and experience in the field.

Various expert sessions were held in 2017 and 2018 to collect all relevant knowledge, evidence, and experience that is currently accessible to develop an improved uniform approach for risk assessment and process steps.

A new dynamic national guideline, including factsheets in various topics being effective by 2019. As a result, a list of topics is formulated for further research.

The new guideline includes the current knowledge and raised awareness among the experts of some important gaps in current evidence on several topics.