215 lines
7.9 KiB
Markdown
215 lines
7.9 KiB
Markdown
# Polio Eradication Progress (1980-2020)
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## Overview
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This interactive globe visualization demonstrates one of the greatest public health achievements in human history: the near-eradication of polio through the Global Polio Eradication Initiative (GPEI). The visualization shows vaccination coverage progression across 70+ countries over 40 years.
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## Visualization Features
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### Interactive Timeline
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- **Year Scrubber**: Slide through 1980-2020 to see vaccination coverage evolution
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- **Play/Pause Controls**: Automatic animation showing decade-by-decade progress
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- **Historical Milestones**: Key events displayed for each significant year
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### Visual Encoding
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**Color Scheme (Vaccination Coverage)**:
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- Deep Red (#f44336): 0-19% coverage - Critical risk areas
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- Orange (#ff9800): 20-39% coverage - Low coverage regions
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- Yellow (#ffeb3b): 40-59% coverage - Moderate progress
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- Light Green (#8bc34a): 60-79% coverage - Good progress
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- Green (#4caf50): 80-100% coverage - Optimal protection
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- Dark Green (#1b5e20): Certified polio-free countries
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**Special Markers**:
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- Green border (2px): Countries certified polio-free by their region's certification year
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- Red border (3px) + Red fill: Endemic countries (Afghanistan & Pakistan in 2020)
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### Interactive Features
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- **Click any country**: View detailed vaccination statistics
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- Current year coverage
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- 1980 baseline coverage
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- 2020 final coverage
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- Total improvement percentage
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- Certification year (if applicable)
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- Endemic status (if applicable)
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- **Globe rotation**: Automatic slow rotation (pauses on user interaction)
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- **Real-time statistics**: Global coverage, certified countries, endemic count, cases prevented
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## Data Sources
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### Primary Data
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- **WHO/UNICEF Estimates**: Coverage of third dose of diphtheria-tetanus-pertussis vaccine containing polio (DTP3) used as proxy for Pol3
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- **GPEI Records**: Global Polio Eradication Initiative historical data
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- **WHO Regional Certifications**: Official polio-free certification dates by region
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### Coverage Methodology
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Data represents the percentage of 1-year-old children who received three doses of polio vaccine (Pol3) for each year from 1980-2020. Coverage estimates are based on:
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- Administrative data from national immunization programs
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- WHO/UNICEF joint reporting forms
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- Coverage surveys and demographic health surveys
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### Regional Certification Dates
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- **Americas**: 1994 (Last case: Peru, 1991)
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- **Western Pacific**: 2000 (Including China, Australia, Pacific islands)
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- **Europe**: 2002 (51 countries certified)
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- **Southeast Asia**: 2014 (Including India - major milestone)
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- **Africa**: 2020 (Wild poliovirus eradicated from continent)
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### Endemic Countries (2020)
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Only 2 countries remain with wild poliovirus transmission:
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1. **Afghanistan**: 84% coverage in 2020, ongoing security challenges
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2. **Pakistan**: 90% coverage in 2020, significant progress but transmission continues
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## Key Historical Milestones
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### 1980 - Pre-GPEI Era
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- Global coverage: ~22% (estimated)
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- ~400,000 polio cases annually worldwide
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- Polio endemic in 125+ countries
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### 1988 - GPEI Launch
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- World Health Assembly resolution to eradicate polio
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- Only 22% global immunization coverage
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- Target: Eradication by year 2000
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### 1991 - Americas Progress
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- Last wild poliovirus case in Peru
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- Western Hemisphere on path to eradication
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### 1994 - First Regional Certification
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- Americas certified polio-free by PAHO
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- Demonstrated eradication was achievable
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### 2000 - Western Pacific Certified
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- China and Western Pacific region certified
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- Massive achievement given population size
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### 2002 - Europe Certified
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- 51 European countries certified polio-free
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- Further reduced endemic countries
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### 2012 - India's Breakthrough
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- India achieves 3 years without polio case
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- Previously considered most challenging country
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### 2014 - Southeast Asia Certified
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- India's inclusion marks turning point
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- Only 3 endemic countries remain (Afghanistan, Pakistan, Nigeria)
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### 2020 - Africa Certified
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- Wild poliovirus eradicated from African continent
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- Nigeria (last African endemic country) certified
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- Only Afghanistan and Pakistan remain endemic
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## Impact Statistics (2020)
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### Cases Prevented
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- **20+ million** paralytic polio cases prevented since 1988
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- **99.9%** reduction in global polio cases
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- From 400,000 annual cases (1980s) to ~140 cases (2020)
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### Vaccination Achievement
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- **90%** global coverage in 2020 (up from 22% in 1988)
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- **2.5 billion** children vaccinated through campaigns
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- **184** out of 186 countries now polio-free
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### Economic Impact
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- $27 billion in treatment costs avoided
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- $40-50 billion total economic benefits
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- Prevented lifetime of disability for millions
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## Technical Implementation
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### Technologies
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- **Mapbox GL JS v3.0.1**: Globe projection with atmosphere effects
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- **GeoJSON**: Country polygon data with temporal vaccination properties
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- **Vanilla JavaScript**: ES6 modules for clean architecture
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### Mapbox Features Used
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1. **Globe Projection**: 3D representation with atmospheric effects
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2. **Dynamic Styling**: Choropleth with expression-based coloring
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3. **Data-Driven Borders**: Variable width/color based on certification status
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4. **Popups**: Interactive country details on click
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5. **Fog Effects**: Space atmosphere for visual appeal
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### Data Structure
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Each country feature contains:
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```javascript
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{
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name: "Country Name",
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coverage_1980: 22, // Baseline
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coverage_1985: 35, // +5 years
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coverage_1990: 48, // +10 years
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coverage_1995: 61, // +15 years
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coverage_2000: 74, // +20 years
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coverage_2005: 82, // +25 years
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coverage_2010: 88, // +30 years
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coverage_2015: 92, // +35 years
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coverage_2020: 95, // +40 years (final)
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polio_free_year: 2000, // Certification year or null
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endemic: false // true only for Afghanistan & Pakistan
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}
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```
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## Educational Value
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### What This Visualization Teaches
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1. **Power of Vaccination**: Shows dramatic improvement from 22% to 90% global coverage
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2. **Regional Approach**: Different regions certified at different times based on progress
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3. **Persistence Required**: 32+ years from GPEI launch to near-eradication
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4. **Final Mile Challenge**: Last 2 endemic countries show difficulty of reaching 100%
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5. **Inequality Patterns**: Developed nations achieved high coverage faster than developing regions
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6. **Success Story**: One of the most successful public health campaigns in history
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### Notable Patterns
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- **Americas led the way**: First region certified (1994), showing leadership
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- **Western Pacific achievement**: Despite population size, certified by 2000
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- **India's transformation**: From "impossible" to certified in 2014
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- **Africa's triumph**: Overcame infrastructure challenges to certify in 2020
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- **Final barriers**: Security, conflict, and access issues in Afghanistan/Pakistan
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## Future Outlook
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### Path to Eradication
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- Focus on Afghanistan and Pakistan
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- Improved security and access in conflict zones
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- Continued high coverage in certified countries
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- Surveillance for vaccine-derived poliovirus
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### What Success Means
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- Would be only the second disease eradicated (after smallpox)
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- Annual savings of $1.5 billion in vaccination costs
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- Blueprint for other disease eradication efforts
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## Development
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### Local Setup
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1. Replace Mapbox token in `src/index.js`
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2. Open `index.html` in web browser
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3. No build process required - vanilla JavaScript
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### Data Updates
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To update data, modify `src/data/data.js`:
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- Add new countries to features array
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- Update coverage values for different years
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- Adjust certification years as regions achieve polio-free status
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## Credits
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**Data Sources**:
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- World Health Organization (WHO)
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- UNICEF
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- Global Polio Eradication Initiative (GPEI)
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- CDC Global Immunization Division
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**Visualization**: Mapbox Globe iteration 10
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**Purpose**: Educational demonstration of vaccine impact and public health success
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**Theme**: Vaccine-Disease Correlation Analysis - Polio Eradication
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---
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*This visualization is part of a series exploring the relationship between vaccination campaigns and disease eradication efforts worldwide.*
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