University:
The University Of Western Ontario
Course:
Biology 2290F | Scientific Method in Biology
Academic year:

2024
Views:

300

Pages:

3
Author:

Kyuwon J.

Public Health Achievements of the 21st Century • Worldwide: – Reductions in child mortality. – Vaccine preventable diseases. – Access to safe water and sanitation. – Malaria prevention and control. – Prevention and control of HIV. – TB control. – Control of neglected tropical diseases. – Tobacco control. – Awareness/response for road safety. – Preparedness and response to global health threats (including pandemics). • USA: – Vaccine preventable diseases. – Prevention and control of infectious diseases. – Tobacco control. – Maternal and infant health. – Motor vehicle safety. – Cardiovascular disease prevention. – Occupational safety. – Cancer prevention. – Childhood lead poisoning prevention. – Public health preparedness/response (including bioterrorism). Factors Leading to Emergence and Re-Emergence of Infectious Diseases • Population growth. • Speed and ease of travel. • International commerce. • Climate change. • Antibiotic misuse/abuse – human and animal. • War and social disruption. • Vaccine refusal. 1 Seasonal Patterns of Influenza Influenza Cases by Season 30 Percentage of Cases 25 20 15 10 5 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Northern Hemisphere Southern Hemisphere Influenza Virus Types Influenza Type Hosts Influenza Influenza Influenza Influenza Humans, birds, pigs High mutation rate; pandemic potential Humans, seals Limited antigenic variation Humans Mild illness; rare Cattle, pigs Emerging; potential zoonotic transmission A B C D Characteristics Table 1: Summary of influenza virus types. Herd Immunity Threshold Calculation • Herd immunity threshold is calculated as: Pc = 1 − 1 R0 where R0 is the basic reproduction number. • For example: – If R0 = 2.5, then P c = 1 − – If R0 = 5.0, then P c = 1 − 1 2.5 1 5.0 = 0.6 or 60%. = 0.8 or 80%. 2 Challenges in Vaccine Development and Uptake • Rapid pathogen mutation (e.g., influenza, SARS-CoV-2, HIV). • Non-sterilizing immunity for some diseases. • Need for vaccines in developing countries. • Public confidence in vaccines undermined by anti-science movements and misleading social media. • Universal vaccine research: – Influenza universal vaccine – testing (phase 1) in USA. – Six-valent influenza vaccine under development by NIAID. 3