In heath care, it’s long been conventional to refer to two or three classes of prevention.
- Primary prevention is about implies stopping a person from developing a problem in the first place. It can be done by
- changing the environment, which has been been the approach of public health services;
- changing people’s behaviour. This is attempted through health education; advertising; legal restrictions, like licensing of pubs; and financial disincentives, like taxation on cigarettes and alcohol; or
- changing people’s physical condition. Vaccination is the obvious example.
- Secondary prevention. This implies identifying a problem in its early stages to prevent its progression, for example through screening of women for breast and cervical cancer.
- The third class, tertiary prevention, is not used as widely as the others, because the category is difficult to distinguish from treatment; it aims to reduce the impact of an illness that has happened, or treating diseases so as to stop them from spreading. To stop cancer recurring, for example, treatment has to be thorough and comprehensive.
It ought to be possible to extend this classification to other things we need to prevent. I don’t claim to know much about terrorism, but it seems to me obvious that we cannot describe policing of any kind as the “front line” dealing with the problem. The front line is primary: the people who occupy it include teachers, religious leaders and the broader public. Primary prevention would aim to change culture, attitudes and behaviour at the source, through social inclusion, education, and civic engagement. Community policing and early detection by the security services – the focus of much of the present debate – are forms of secondary prevention. Control orders or the “Prevent” programme, which respond to stop committed terrorists from acting on their convictions, are tertiary. The response of successive governments in the UK has been heavily geared to tertiary prevention, and that means that while it can limit the damage, it comes in too late for effective prevention.