What are the basics of measles and its importance?

Measles: Basic Facts and Importance

Measles is a highly contagious, potentially fatal, but vaccine-preventable viral disease that requires aggressive vaccination campaigns for prevention, as it can lead to severe complications including pneumonia, encephalitis, and death, particularly in vulnerable populations. 1

Clinical Characteristics and Disease Burden

Measles is characterized by:

• Incubation period of 10-12 days from exposure to prodrome and 14 days from exposure to rash (range: 7-18 days) 2
• Clinical presentation includes:
  • Fever ≥38.3°C (≥101°F)
  • Generalized maculopapular rash lasting ≥3 days
  • At least one of: cough, coryza (runny nose), or conjunctivitis 1
  • Pathognomonic Koplik spots (enanthem) 3

Before vaccination was available:

• An estimated 3-4 million people in the US acquired measles annually 2
• Approximately 500,000 cases were reported yearly, resulting in:
  • 500 deaths
  • 48,000 hospitalizations
  • 1,000 cases of permanent brain damage from encephalitis 2

Complications and Severity

Measles can cause severe complications in 10-40% of patients 3:

• Common complications include:

  • Diarrhea
  • Middle ear infection (otitis media)
  • Bronchopneumonia
  • Laryngotracheobronchitis
  • Stomatitis 4

• Serious complications include:

  • Encephalitis (1 per 1,000 cases) - can lead to permanent brain damage
  • Death (1-2 per 1,000 cases in the US; up to 25% in developing countries) 2
  • Subacute sclerosing panencephalitis (SSPE) - rare but fatal degenerative CNS disease 2, 5

• High-risk populations:

  • Infants and young children
  • Adults
  • Pregnant women (increased risk of premature labor, spontaneous abortion, low birth weight)
  • Immunocompromised individuals (may have atypical presentation without rash) 2, 1

Transmission and Contagiousness

Measles is one of the most contagious diseases known:

• Transmitted primarily via respiratory aerosols/droplets 1
• Contagious period: 4 days before rash appearance to 4 days after rash onset 1
• Virus can remain active on surfaces for several hours 1
• Almost every infection becomes clinically manifest 5
• Causes long-lasting memory B and T cell impairment, predisposing to opportunistic infections for years 5

Prevention Through Vaccination

Vaccination is the cornerstone of measles prevention:

• MMR (measles, mumps, rubella) vaccine is highly effective and well-tolerated 6

• Current vaccination schedule:

  • First dose at 12-15 months
  • Second dose at 4-6 years 2, 1
  • In countries with high transmission rates, WHO recommends first dose at 9 months 3

• Vaccination impact:

  • Decreased reported cases by >99% 2
  • Saved millions of lives globally 6
  • Nearly eliminated SSPE in the US 2
  • Measles was declared eliminated from the US in 2000 2

Current Challenges

Despite vaccination success, challenges remain:

• Measles is still endemic in many countries with approximately 107,500 deaths in 2023, mostly in children under five 7
• Requires >95% vaccination rate with two doses to achieve herd immunity 5
• Decreasing vaccination rates and COVID-19 pandemic disruptions threaten progress 4, 7
• International importations continue to cause outbreaks 2
• One confirmed case constitutes a public health emergency 1

Management Approach

For confirmed cases:

• Supportive care is the mainstay of treatment 4
• Vitamin A supplementation is recommended for all children with clinical measles 1
• Antibiotics only for secondary bacterial infections 1
• Isolation for at least 4 days after rash onset 1
• No specific antiviral therapy is available 4
• Immediate reporting to public health authorities is required 1

Why Measles Control Is Important

Measles control is critical because:

1. It's highly contagious and potentially fatal
2. It causes significant morbidity and mortality, especially in vulnerable populations
3. It leads to long-term immune suppression, increasing susceptibility to other infections
4. It's preventable through safe, effective vaccination
5. Global eradication is theoretically possible since humans are the only reservoir 6, 5

Maintaining high vaccination coverage and strong surveillance systems remains essential to prevent resurgence of this serious but preventable disease.