Measles (Human)

Primary reference(s)

WHO, 2019. Measles. World Health Organization (WHO). Accessed 11 September 2020.

Additional scientific description

Despite a long-running, global, childhood routine immunisation programme, measles has been resurgent in recent years, and countries which had previously achieved good control have experienced new outbreaks. Even though a safe and cost-effective vaccine is available, in 2018, there were more than 140,000 measles deaths globally, mostly among children under the age of five (WHO, 2019a).

Measles is a highly contagious viral disease which affects susceptible individuals of all ages and remains one of the leading causes of death among young children globally, despite the availability of safe and effective measles-containing vaccines. It is transmitted via droplets from the nose, mouth, or throat of infected persons. Initial symptoms, which usually appear 10 to 12 days after infection, include high fever, usually accompanied by one or more of the following: runny nose, conjunctivitis, cough and tiny white spots on the inside of the mouth. Several days later, a rash develops, starting on the face and upper neck and gradually spreads downwards. A patient is infectious four days before the start of the rash to four days after the appearance of the rash. Most people recover within two to three weeks (WHO, 2019b).

Detection of specific immunoglobulin M (IgM) antibodies in a serum sample collected within the first few days of rash onset can provide presumptive evidence of a current or recent measles virus infection. Serological tests can result in false-negative results when serum specimens are collected too early with respect to rash onset (CDC, 2019).

Serious complications are more common in children under the age of 5 years, or in adults over the age of 30 years. The most serious complications include blindness, encephalitis (an infection that causes brain swelling), severe diarrhoea and related dehydration, ear infections, or severe respiratory infections such as pneumonia (CDC, 2019; WHO, 2019a).

Even with implementation of routine immunisation, measles continues to circulate globally due to suboptimal vaccination coverage and population immunity gaps. Any community with less than 95% population immunity is at risk for an outbreak. If an outbreak response is not timely and comprehensive, the virus will find its way into more pockets of vulnerable individuals and potentially spread within and beyond the affected countries (WHO, 2019b).

The impact on public health will persist until the ongoing outbreaks are controlled, routine immunisation coverage is continuously high (≥95%) and immunity gaps in the population are closed. As long as measles continues to circulate anywhere in the world, no country can be assured to avoid importation. However, countries can protect their populations through high vaccine coverage achieved primarily through routine immunisation programmes, and where necessary through supplemental immunisation activities designed to ensure that susceptible individuals are vaccinated (WHO, 2019b).

Although the measles virus is related to several other viruses that infect animals, humans are the only reservoir for the measles virus. It is therefore theoretically possible that measles, could be eradicated from the world (ECDC, no date). 

Metrics and numeric limits

Not applicable.

Examples of drivers, outcomes and risk management

World Health Organization (WHO) advice states that immunisation is the most effective preventive measure against measles. Two doses of measles-containing-vaccine are recommended to ensure immunity. While there is no specific antiviral treatment for measles, prompt provision of vitamin A is recommended by WHO for all children infected with measles. It is critical to quickly recognise and treat complications of measles in order to reduce mortality and severity of disease (WHO, 2019b).

The WHO (2019b) urged all Member States to do the following: 

• Maintain high measles vaccination coverage (≥95%) with two doses of measles-containing-vaccine, in every district.
• Offer vaccination to individuals who do not have proof of vaccination or immunity against measles, and who are at risk of infection and transmission of the virus, such as healthcare workers, people working in tourism and transportation, and international travellers.
• Strengthen epidemiological surveillance for cases of ‘fever with rash’ for timely detection of all suspected cases of measles in public and private healthcare facilities.
• Ensure that collected blood samples from suspect measles cases are appropriately tested by laboratories within five days.
• All countries need to provide a rapid response to imported measles cases to prevent the establishment or re-establishment of endemic transmission.
• Recognise complications early and provide comprehensive treatment to reduce the severity of disease and avoid unnecessary deaths.
• Administer vitamin A supplementation to all children diagnosed with measles to reduce complications and mortality: two doses of 50,000 IU for a child less than 6 month of age, 100,000 IU for children between 6 and 12 months of age or 200,000 IU for children 12 to 59 months of age, immediately upon diagnosis and on the following day.
• Ensure health care workers are vaccinated in order to avoid infections acquired in a health care setting. 

The WHO and partners coordinate their support to Member States via their public health response by calling for the following activities: enhancing preparedness for measles outbreak response; strengthening public trust in vaccines; strengthening surveillance, risk assessment and outbreak investigations; improving clinical management of measles cases; implementing outbreak response immunisation activities; and evaluating outbreak response activities (WHO, 2019b).

The WHO has established a measles outbreaks Incident Management Support system to coordinate its support to affected countries (WHO, 2019b).