What Is Measles?
Measles is a highly contagious viral disease caused by the measles virus, a member of theParamyxoviridaefamily. It spreads through respiratory droplets when an infected person coughs or sneezes, and the virus can remain airborne for up to two hours. Typical symptoms appear 1014 days after exposure and include high fever, cough, runny nose, red eyes, and a characteristic redbrown rash that starts on the face and spreads downward.
Complications can be severe, especially in young children, malnourished individuals, or people with weakened immune systems. These complications include pneumonia, encephalitis, otitis media, severe diarrhoea, and, in rare cases, death. Before the introduction of a vaccine, measles caused an estimated 2.6 million deaths each year worldwide.
Why Immunisation Is Crucial
Vaccination is the single most effective tool for preventing measles. The measles vaccine provides strong, longlasting immunity and has an excellent safety record. When enough people are immunised, community (or herd) immunity is achieved, reducing the chance that the virus can find a susceptible host.
Herd immunity for measles requires about 95% of the population to be vaccinated because the virus is so contagious (basic reproduction numberR1218). Below this threshold, outbreaks can occur rapidly, as seen in recent resurgences linked to vaccine hesitancy and gaps in routine immunisation programs.
The Vaccine
The measles vaccine is usually given as part of the combined measlesmumpsrubella (MMR) or measlesmumpsrubellavaricella (MMRV) preparation. It contains a liveattenuated (weakened) virus that stimulates the immune system without causing disease.
- Schedule: In most countries the first dose is administered at 1215months of age, with a second dose at 46years (or before school entry). In some regions, an earlier dose at 69months is recommended for infants at high risk.
- Efficacy: One dose provides about 93% protection; two doses raise efficacy to >97%.
- Safety: Common side effects are mildpain at the injection site, lowgrade fever, or rash. Serious adverse events are extremely rare (approximately 1 in a million).
Who Should Get Vaccinated?
Routine measles immunisation is recommended for all children according to the national schedule. Additional groups should receive the vaccine or a booster dose:
- Adolescents and adults who have not received two documented doses or lack evidence of immunity.
- Pregnant women who are not immune (vaccination should be deferred until after delivery).
- Healthcare workers, teachers, and anyone who works with vulnerable populations.
- Travelers to regions where measles is still endemic.
Addressing Common Concerns
The vaccine can cause measles. The liveattenuated virus in the vaccine is weakened so it cannot cause the disease in healthy individuals. Immunocompromised persons should avoid the vaccine and seek passive immunisation (immune globulin) if exposed.
I heard it causes autism. Multiple largescale studies have found no link between the MMR vaccine and autism. The myth originated from a discredited 1998 study that has been thoroughly retracted.
My child is too young. While the first dose is given at 1215months, infants born to immune mothers may receive an early dose at 69months in outbreak settings. The early dose does not replace the routine twodose schedule.
Global Impact of the Measles Vaccine
Since the introduction of the measles vaccine in the 1960s, global mortality has dropped dramatically. The World Health Organization (WHO) estimates that measles deaths fell by 73% between 2000 and 2018, saving an estimated 23 million lives.
However, measles remains endemic in several lowincome countries, and periodic outbreaks continue in highincome nations where vaccination coverage slips below the herdimmunity threshold. Strengthening routine immunisation, maintaining accurate coverage data, and rapid outbreak response are essential to sustain progress.
What To Do If You Suspect Measles
- Isolate the patient. Keep the person at home and avoid contact with unvaccinated individuals.
- Seek medical advice. A healthcare professional can confirm diagnosis (clinical assessment and laboratory testing) and advise on supportive care.
- Notify publichealth authorities. Prompt reporting helps trigger contacttracing and vaccination campaigns.
- Verify immunity of close contacts. Offer MMR vaccine to anyone unvaccinated or with uncertain status, ideally within 72hours of exposure.
How You Can Help
Everyone can contribute to measles elimination:
- Ensure that your children receive both recommended doses of MMR on schedule.
- Check your own vaccination status and get a booster if needed.
- Support local immunisation programmes through volunteering or advocacy.
- Share accurate information and debunk myths on social media.
- Donate to organisations that provide vaccines to underserved communities.
Further Reading & Resources
For detailed guidelines and the latest data, visit:
