What is measles?

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Last updated: February 28, 2025View editorial policy

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From the Guidelines

Measles is a highly contagious viral disease caused by the measles virus (rubeola) that can lead to serious complications, including pneumonia, encephalitis, and even death, particularly in young children, pregnant women, and immunocompromised individuals. The disease typically begins with symptoms like high fever, cough, runny nose, and red, watery eyes, followed by a characteristic red rash that spreads from the face to the rest of the body 1. Measles is caused by rubeola virus, a paramyxovirus of the genus Morbillivirus, and is known to be spread through droplet transmission from the nose, throat, and mouth of infected persons if they cough or sneeze 1.

Some key points to consider about measles include:

  • The virus can remain infectious in the air for up to two hours after an infected person leaves the area
  • Measles can be prevented through vaccination with the MMR (measles, mumps, rubella) vaccine, which is typically given in two doses - the first at 12-15 months of age and the second at 4-6 years 1
  • The vaccine is highly effective, providing about 97% protection after two doses
  • Measles remains a significant public health concern globally despite the availability of a safe and effective vaccine, with outbreaks occurring in areas with low vaccination rates
  • In 2013, more than 20 million infections of measles occurred worldwide, causing around 145,000 deaths 1

It's worth noting that the MMR vaccine has been shown to be highly effective in preventing measles, with a vaccine coverage of 91.5% of children aged 19–35 months in the United States having received 1 dose of MMR vaccine in 2010 1. However, measles remains a significant public health concern globally, and outbreaks can occur in areas with low vaccination rates. Therefore, it is essential to prioritize vaccination and maintain high vaccination rates to prevent the spread of measles and its associated complications.

From the Research

Definition and Characteristics of Measles

  • Measles is a highly contagious illness that classically presents with a rash, fever, cough, coryza, and conjunctivitis 2.
  • It is a highly communicable viral infection with serious complications 3.
  • Measles is a highly contagious, potentially fatal, but vaccine-preventable disease caused by measles virus 4.
  • The illness typically begins with fever, runny nose, cough, and pathognomonic enanthem (Koplik spots) followed by a characteristic erythematous, maculopapular rash 5.

Transmission and Diagnosis

  • Transmission of measles is dependent on person-to-person spread through respiratory droplets or direct contact 3.
  • Diagnosis is based on recognizing the clinical picture and can be confirmed with results of laboratory testing, such as serologic tests or polymerase chain reaction 3.
  • Laboratory diagnosis relies largely on the detection of specific IgM antibodies in serum, dried blood spots, or oral fluid, or the detection of viral RNA in throat or nasopharyngeal swabs, urine, or oral fluid 4.

Complications and Treatment

  • Complications from measles are relatively common and can be associated with significant morbidity and mortality 2.
  • Complications can affect many organs and often include otitis media, laryngotracheobronchitis, pneumonia, stomatitis, and diarrhoea 4.
  • Treatment is mainly supportive, such as vitamin A supplementation, monitoring for and treatment of secondary bacterial infections with antibiotics, and rehydration in the case of severe diarrhoea 4.
  • There is no specific antiviral therapy for the treatment of measles, and disease control largely depends on prevention 4.

Prevention and Vaccination

  • Vaccination against measles is effective, cost-effective, and safe 3.
  • Measles can be eliminated from a population; this outcome requires coverage with 2 doses of vaccine at rates of 93% to 95% of the population 3.
  • The World Health Organization recommends that the first and second doses of measles-containing vaccine be given at ages 9 months and 15 to 18 months, respectively, in countries with high rates of measles transmission 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

An Update and Review of Measles for Emergency Physicians.

The Journal of emergency medicine, 2020

Research

Measles and Measles Vaccination: A Review.

JAMA pediatrics, 2016

Research

Measles.

Lancet (London, England), 2022

Research

Measles: a disease often forgotten but not gone.

Hong Kong medical journal = Xianggang yi xue za zhi, 2018

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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