Prevention

The prevention of infectious diseases involves the implementation of interventions, either at population or individual level, which aim to prevent outbreaks and halt or minimise the burden of these diseases. Five levels of disease prevention are generally recognised, each of which focuses on the stage at which the preventive strategy is applied:

Primordial: addresses common risk factors of infectious diseases such as climate, environmental, social-behavioural, and healthcare systems. Examples include health promotion and increasing health literacy

Primary: comprises services and activities aimed at avoiding infection, e.g. immunisation against disease or pre-exposure prophylaxis (PrEP) for HIV

Secondary: aims to detect and address an existing disease prior to the appearance of symptoms. Examples include screening for latent tuberculosis infection or genital chlamydia infection

Tertiary: consists of methods to reduce the harm caused by disease through rehabilitation and treatment, such as physical therapies for children with paralytic polio

Quaternary: aims to avoid or reduce results of unnecessary or excessive interventions in the healthcare system, for example, antimicrobial awareness and stewardship

The public health concepts of preparedness and control are complementary to but different from prevention. Preparedness refers to the readiness and capacity of systems, organisations, and communities, and consists of measures undertaken in advance of an outbreak to respond and cope with public health emergencies. By contrast, control aims to contain the spread of diseases, mitigate their impact on affected individuals and communities, and prevent further transmission.