Interventions in communicable disease control are by preference guided by evidence, coming from existing scientific knowledge and newly generated by assessment methods for burden of disease and field epidemiology.

Interventions are aimed to prevent or interrupt transmission of an infectious agent to hosts and may be proactive (prevention measures) or reactive (control response measures). Each of those measures can be targeted at critical control points' in the chain of transmission of infectious agents (see figure).

For example, measures targeting reservoirs may include rodent control / extermination in case of leptospirosis or culling of poultry flocks in case of avian influenza. A large portion of control measures include measures targeted at specific sources,  for example remove botulism contaminated olives from the market or searching for an infectious tuberculosis patient in order to treat the infection.

Examples of measures targeted at transmission routes include vector control, behavioural education (e.g. safe sex, safe cooking, promotion of hand hygiene) and treatment of drinking water. Interventions targeting barriers around the host could include provision of personal protective equipment, treatment and covering of skin lesions. Among the most well known intervention measures are immunisations (vaccinations and prophylaxis through immunuglobulins) to enhance the specific immunity against micro organisms.

Finally, treatment and / or quarantine of infectious patients or carriers ensure that risk of person to person transmission is reduced in certain diseases.

Question:

What is the difference between preventive measures, response control measures and intervention measures?

Reflection:

In various textbooks and articles, these terms are used in different ways. In the FEMWiki, we prefer the following distinction:

Preventive interventions in communicable disease control:

  1. Primary prevention: Intervention in the population, targeting healthy population (i.e. not infected) at risk in order to avoid infection (e.g. immunisations)
  2. Secondary prevention: intervention in the population infected, in order to mitigate symptomatic disease or avoid complications (e.g. screening)
  3. Tertiary prevention: intervention targeting the population with disease symptoms aimed at limiting the impaired functions in daily life or society, due to the disease (e.g. rehabilitation regimes for paralytic polio patients)

In addition to these 3 levels of preventive interventions, a more generic level is often used: primordial prevention, which includes generic measures such as improvements in civil engineering (clean drinking water, sewage systems etc).

Communicable disease control response measures that do not include primary, secondary or tertiary prevention are for example treatment or quarantine of carriers, culling of infected poultry flocks or removing certain food items from the market.

However it is important to be aware that these classifications of prevention are under debate in public health, since they do not offer a complete framework for disease prevention and control, and several alternatives have been suggested.

References

  1. Barbara Starfield. Public Health and Primary Care: A Framework for Proposed Linkages. Am J Public Health, 1996 Oct.;86(10):1365–1369.
  2. B Starfield, J Hyde, J Gérvas, I Heath. The concept of prevention: a good idea gone astray? J Epidemiol Community Health 2008;62:580–583. doi:10.1136/jech.2007.071027