Measles is a highly contagious disease caused by the measles virus, primarily transmitted through airborne droplets. This virus can survive in the air for several hours, and unvaccinated individuals are at extremely high risk of infection upon exposure. The World Health Organization classifies it as a preventable infectious disease, but outbreaks still occur in some areas due to insufficient vaccination coverage.
This disease is more common in children, but adults without immunity can also become infected. Typical symptoms include high fever, cough, and characteristic rashes; severe cases may lead to complications such as pneumonia or encephalitis. The World Health Organization indicates that vaccination with the MMR vaccine (measles, mumps, and rubella combined vaccine) is currently the most effective preventive measure.
The RNA genome of the measles virus is encapsulated in a lipid envelope, making it extremely contagious. When an infected person coughs or sneezes, the virus can remain suspended in the air, and individuals without immunity will show symptoms approximately 7 to 18 days after inhalation. The virus can survive in the environment for several hours, making public places or enclosed spaces prone to outbreaks.
High-risk groups include:
Additionally, areas with scarce medical resources or communities with low vaccination rates have a higher risk of outbreaks. The virus first replicates in the upper respiratory tract before spreading throughout the body, leading to an overreaction of the immune system, which may damage the respiratory system and skin.
The incubation period is about 10 to 14 days, and initial symptoms resemble those of influenza, including high fever (which can exceed 39.5°C), conjunctivitis, and cough. Patients typically exhibit the "three C's" symptoms: cough, conjunctivitis, and Koplik's spots (small white spots in the mouth), which are important clinical indicators for diagnosis.
The characteristic rash appears 3 to 4 days after the fever begins, starting behind the ears and gradually spreading throughout the body. The skin exhibits red maculopapular rashes that may merge into larger patches, with significant itching. Severe cases may be accompanied by:
About 30% of patients may experience complications, with pneumonia being the most common severe complication, and mortality rates can reach 1-2% in underdeveloped areas. A very small number of cases may develop subacute sclerosing panencephalitis (SSPE) years after infection, which is a progressive neurological disease caused by reactivation of the latent virus.
Diagnosis is primarily based on clinical symptoms and epidemiological history. Physicians will observe the development of Koplik's spots and skin rashes and inquire about exposure history or vaccination records. In suspected outbreak situations, laboratory tests can confirm the diagnosis.
Common laboratory methods include:
During the diagnostic process, it is necessary to differentiate from rubella, chickenpox, or other febrile exanthematous diseases. For example, rubella symptoms are milder and may present with swollen lymph nodes behind the ears, while chickenpox rashes are vesicular and distinctly different from measles' maculopapular rashes.
Currently, there are no specific antiviral medications, and treatment is mainly supportive. Hospitalization is usually reserved for patients with severe dehydration or pneumonia complications. Common management strategies include:
Severe patients may require intensive care monitoring and antibiotic treatment for secondary bacterial infections. Importantly, vaccinated individuals who become infected typically experience milder symptoms and a reduced risk of complications.
Vaccination is the key measure to prevent measles. Two doses of the MMR vaccine (measles, mumps, and rubella combined vaccine) can provide over 97% protection. The vaccination schedule typically involves administering the first dose at 12 to 15 months and a booster dose at 4 to 6 years.
During an outbreak, high-risk groups who have been exposed to patients may consider receiving immune globulin for immediate protection. Public health measures include:
The global initiative to eliminate measles emphasizes that vaccination coverage must exceed 95% to achieve herd immunity. In recent years, vaccine hesitancy has led to decreased coverage in some areas, contributing to resurgence.
If a high fever is accompanied by a characteristic rash, or if fever develops after contact with a confirmed case, immediate medical attention is necessary. The following situations require urgent care:
Pregnant women, individuals with immune system deficiencies, or infants under 6 months old who exhibit suspected symptoms should seek immediate medical attention. Even vaccinated individuals should receive professional evaluation if they develop atypical symptoms after exposure.
About 5% of individuals may develop a mild rash within 2-3 weeks after receiving the live measles vaccine, which is a normal reaction caused by the weakened strain in the vaccine and not a true measles infection. This phenomenon usually requires no treatment and will resolve on its own within a few days, but it is advisable to monitor for any other severe symptoms after vaccination.
What other methods can prevent infection after exposure to a measles patient?Within 72 hours of exposure to measles, vaccination with measles immune globulin (MMR immune globulin) can reduce the risk of infection, especially for unvaccinated infants or individuals with compromised immunity. If vaccinated, individuals typically have sufficient protection but should still monitor for symptoms.
Will there be permanent damage after recovering from measles?The vast majority of patients do not experience sequelae after recovery; however, severe complications such as encephalitis or intrauterine infections may lead to neurological damage. Younger patients or those with low immunity are at higher risk, and regular health follow-ups should be conducted after recovery to ensure no long-term effects.
What impact does measles infection during pregnancy have on the fetus?Pregnant women infected with measles may have an increased risk of miscarriage or premature birth, and intrauterine infection may lead to fetal developmental abnormalities. If infection is suspected, immediate medical attention should be sought, and health authorities should be notified, but vaccination should be avoided until after delivery.
Why do measles patients need to be isolated until four days after the rash appears?The measles virus is highly contagious from two days before to four days after the rash appears; during this period, droplets expelled by the patient or contact with contaminated objects may transmit the virus. Isolating until four days after the rash appears effectively interrupts transmission, especially in enclosed spaces or densely populated areas.
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