Measles is a highly contagious viral infection caused by the measles virus, a member of the Paramyxoviridae family. It primarily affects children but can occur in unvaccinated individuals of any age. The virus spreads through respiratory droplets from infected individuals when they cough or sneeze. It can remain in the air and on surfaces for several hours, making it highly transmissible. While measles is preventable, outbreaks still occur, particularly in areas with low vaccination coverage, leading to significant morbidity and mortality worldwide.
The disease progresses through several stages, beginning with an incubation period of 10–14 days, followed by the prodromal phase, characterized by fever, cough, coryza and conjunctivitis. The hallmark of measles is the appearance of Koplik spots, small bluish-white lesions on the inner lining of the cheeks, preceding the development of a widespread maculopapular rash. Without proper medical intervention, measles can lead to severe complications.
This article explores the diagnosis and prevention strategies for measles.
Diagnosis of Measles
1.Clinical Diagnosis
Measles is typically diagnosed based on its characteristic symptoms, which include:
a. High Fever, with temperature ≤105°F (≤40.6°C)
b. Cough, Coryza and Conjunctivitis
c. Koplik Spots, Small, bluish-white spots with a red background on the inner lining of the cheeks, appearing 1-2 days before the rash.
d. Maculopapular Rash, A widespread red rash that starts on the face and spreads downward to the neck, trunk and extremities.
2. Laboratory Confirmation
Since other viral illnesses can present with similar symptoms, laboratory tests are used for confirmation:
a. Serologic Testing: Detection of measles-specific IgM antibodies in serum, which typically appear within three days of rash onset and remain detectable for several weeks.1
b. Measles PCR Test:2 Measles RT-PCR (Reverse Transcription Polymerase Chain Reaction) is a highly sensitive and specific test used to detect measles viral RNA in clinical specimens. This test is particularly valuable during the early phase of the disease, shortly after symptom onset, when the virus is actively replicating in the body. To maximize detection, healthcare providers may collect specimens as early as possible after symptoms appear. RT-PCR can confirm measles even before IgM antibodies are detectable, making it crucial for early diagnosis and outbreak control.
The preferred specimens include Nasopharyngeal Swab, Throat Swab and Urine Sample.
Prevention of Measles
1. Vaccination
The most effective way to prevent measles is through vaccination:
a. Measles, Mumps, and Rubella (MMR) Vaccine:
The MMR vaccine (Measles, Mumps and Rubella vaccine) is a live attenuated vaccine. It contains weakened forms of viruses that cause measles, mumps and rubella. These weakened viruses cannot cause diseases in healthy individuals, but they are strong enough to stimulate an immune response, leading to the production of antibodies that provide long-term immunity.3 However, because it is a live vaccine, it is not recommended for individuals with weakened immune systems, such as those undergoing chemotherapy or with certain immunodeficiencies.
Recommended MMR Vaccination Schedule:-
a. First Dose:
○ Given at 9 months in countries where measles is common (high endemicity) because early protection is crucial.4
○ Given at 12–15 months in countries where measles is less common.4
b. Second Dose:
○ Given at 15–18 months in some countries.4
○ In many countries, it is given at 4–6 years to ensure long-term immunity.5
b. Measles, Mumps, Rubella, and Varicella (MMRV) Vaccine:
The MMRV vaccine is a combination vaccine that protects against measles, mumps, rubella and varicella (chickenpox). It is an extension of the MMR vaccine, with the addition of the varicella (chickenpox) vaccine. This vaccine is made using live attenuated (weakened) viruses, which help the immune system recognize and fight these diseases without causing the actual infections.
Recommended MMRV Vaccine Schedule:-
a. First Dose (12–15 months old):5
The first dose is given once the child is at least 12 months old because maternal antibodies (which can interfere with vaccine effectiveness) typically decline by this age.
b. Second Dose (4–6 years old):5
The second dose is usually given before a child starts school (around 4–6 years old). However, it can be given as early as 3 months after the first dose, if necessary, particularly in situations where early protection is needed (such as during an outbreak or for international travel).
c. Catch-up Vaccination:
Unvaccinated adolescents and adults should receive two doses at least 4 weeks (28 days) apart.6
2. Herd Immunity
Herd immunity, also called population immunity, occurs when a large percentage of a community becomes immune to an infectious disease, making it difficult for the disease to spread. This provides indirect protection to individuals who are not immune, such as newborns, elderly people or those with weakened immune systems.7
Herd immunity can develop in two ways:
a. Vaccination (Preferred Method by WHO)
○ When a large portion of the population is vaccinated, the disease has fewer opportunities to spread, leading to a significant decline in infections.
○ Vaccines train the immune system to recognize and fight the disease without causing the actual illness, making it a safe and effective way to achieve immunity.
○ WHO supports herd immunity through vaccination because it prevents unnecessary deaths, reduces long-term health complications and protects those who cannot be vaccinated
b. Natural Infection (Not Recommended by WHO)
If many people get infected and recover, they may develop natural immunity. However, this approach is dangerous because:
○ It can cause severe illness, complications or death, especially in vulnerable groups.
○ The virus can mutate, reducing the effectiveness of natural immunity.
○ Healthcare systems can become overwhelmed due to large outbreaks.
3. Post-Exposure Prophylaxis
Post-exposure prophylaxis (PEP) for measles is a preventive measure given after exposure to the virus to either prevent infection or reduce disease severity in individuals who are not immune.
There are two types of Post-Exposure Prophylaxis for individuals exposed to measles, who are unvaccinated:
a. MMR Vaccine: Healthy, non-immune individuals (≥6 months old) must be administered with MMR vaccine within 72 hours (3 days) of exposure.
b. Immunoglobulin (IG): Recommended for immunocompromised individuals, pregnant women and infants under six months who are exposed to measles and must be administered within 6 days of exposure.
Administering the MMR vaccine and immunoglobulin (IG) together is not recommended because IG can neutralize the live attenuated viruses in the vaccine, making the vaccine ineffective.8
4. Public Health Measures
a. Isolation of Infected Individuals:9
Measles is highly contagious and spreads through respiratory droplets and airborne transmission. The infectious period begins four days before the rash appears and lasts until four days after its onset. Patients with suspected or confirmed measles should be isolated at home or in healthcare settings, preferably in negative pressure rooms if hospitalized. They should be restricted from public places, schools and workplaces until they are no longer infectious to prevent further transmission. Supportive care including adequate hydration, fever management and vitamin A supplementation should be provided to help reduce complications and promote recovery.
b. Health Education:
It is essential to raise awareness about the symptoms, complications and preventive measures of measles through comprehensive community education programs. Emphasizing the importance of vaccination is crucial in preventing outbreaks and safeguarding public health. Additionally, it is important to strongly discourage practices such as hosting “measles parties” to intentionally expose individuals to the virus, as this approach is not recommended by the World Health Organization (WHO). Natural herd immunity achieved through such methods can lead to unnecessary illness, complications, and even death, making vaccination the safest and most effective strategy for disease prevention.
c. Surveillance and Outbreak Response:
Effective surveillance and rapid reporting are critical in the event of a measles outbreak. Prompt identification and investigation of suspected measles cases enable health authorities to quickly implement containment measures and prevent further spread.9 Timely reporting ensures that outbreak control strategies, such as vaccination campaigns, isolation of infected individuals and contact tracing, can be deployed without delay, minimizing the impact of the outbreak and protecting vulnerable populations.
Conclusion
Measles remains a highly contagious and preventable disease, with significant morbidity and mortality, particularly in regions with low vaccination coverage. The most effective strategy for preventing measles is widespread vaccination, with the MMR and MMRV vaccines playing a key role in safeguarding public health. Achieving herd immunity through vaccination is critical to reducing the spread of the virus and protecting vulnerable populations who cannot receive the vaccine.
Post-exposure prophylaxis, through the MMR vaccine or immunoglobulin is also an important tool in reducing disease severity following exposure. To control outbreaks, early diagnosis through clinical symptoms and laboratory testing is essential, alongside immediate isolation of infected individuals and rapid outbreak response measures. Effective public health education programs help raise awareness about the importance of vaccination, the risks of natural herd immunity and the dangers of measles parties. With strong surveillance systems and coordinated outbreak response strategies, measles can be prevented and controlled, ensuring the protection of individuals and communities.
In conclusion, vaccination remains the cornerstone of measles prevention. By continuing to prioritize vaccination, robust public health education and quick response during outbreaks, we can significantly reduce the burden of measles worldwide and move closer to achieving global measles elimination.
References
- Clinical Overview of Measles. CDC. Published on July 15, 2024. Accessed on March 14, 2025. Available from: https://www.cdc.gov/measles/hcp/clinical-overview/index.html
- Public Health Ontario. Measles – Diagnostic – PCR. Public Health Ontario. Accessed on March 14, 2025. Available from: https://www.publichealthontario.ca/en/Laboratory-Services/Test-Information-Index/Measles-Diagnostic-PCR
- Bailey A, Patel P, Sapra A. MMR Vaccine. [Updated 2024 Feb 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK554450
- Measles. WHO. Published on November 14, 2024. Accessed on March 15, 2025. https://www.who.int/news-room/fact-sheets/detail/measles
- Measles Vaccination. CDC. Published on January 17, 2025. Accessed on March 15, 2025. https://www.cdc.gov/measles/vaccines/index.html?CDC_AA_refVal=https%3A%2F%2Fwww.cdc.gov%2Fvaccines%2Fvpd%2Fmmr%2Fpublic%2Findex.html
- Catch-up Immunization Schedule for Children and Adolescents. CDC. Published on November 21, 2024. Accessed on March 15, 2025. Available from: https://www.cdc.gov/vaccines/hcp/imz-schedules/child-adolescent-catch-up.html
- Coronavirus disease (COVID-19): Herd immunity, lockdowns and COVID-19. Updated 31 December 2020. Accessed on March 15, 2025. Available from: https://www.who.int/news-room/questions-and-answers/item/herd-immunity-lockdowns-and-covid-19#:~:text=’Herd%20immunity’%2C%20also%20known,immunity%20developed%20through%20previous%20infection.
- Measles Vaccine Recommendations. CDC. Published on September 20, 2024. Accessed on March 15, 2025. Available from: https://www.cdc.gov/measles/hcp/vaccine-considerations/index.html#:~:text=Post%2Dexposure%20prophylaxis%20for%20measles&text=To%20potentially%20provide%20protection%20or,within%206%20days%20of%20exposure.
- Gastañaduy PA, Banerjee E, DeBolt C, Bravo-Alcántara P, Samad SA, Pastor D, Rota PA, Patel M, Crowcroft NS, Durrheim DN. Public health responses during measles outbreaks in elimination settings: Strategies and challenges. Hum Vaccin Immunother. 2018;14(9):2222-2238. https://pmc.ncbi.nlm.nih.gov/articles/PMC6207419/#S0002
