Epidemiology Lecture Notes

Definition and Scope

• Epidemiology: Study of the emergence, distribution, and control of disease, disability, and death in populations.
• Combines elements from various fields:
  • Biology
  • Clinical Medicine
  • Sociology
  • Mathematics
  • Ecology

Role of Epidemiologists

• Professionals: Doctors and scientists.
• Objectives:
  • Understand the source of diseases.
  • Estimate exposure levels.
  • Track the spread of diseases.
• Areas of Study:
  • Infectious diseases (e.g., COVID-19 pandemic)
  • Non-infectious health issues (e.g., lung cancer from smoking, community violence rates)

Epidemiologic Triangle

• A tool to explain disease causation and spread conditions.
• Three Corners:
  • Who: Host or people with the disease.
  • What: Agent or cause of the disease.
  • Where: Environment in which the disease occurs.
• Objective: Break the connection between host, agent, and environment to stop disease spread.

Case Study: COVID-19 Pandemic

• Early March 2020: Imperial College London's epidemiologists released a model during the pandemic.
• Model Insights:
  • Showed potential impacts if prevention methods were implemented or not.
  • Recommended large-scale social distancing.
• Outcome:
  • Severed the connection between 'where' and 'who'.
  • Resulted in fewer cases and deaths.
  • Recommendations influenced public policy worldwide.