Measles

The clinical signs of measles usually appear between 6 and 21 days after exposure to the virus. They develop in several successive phases.
The disease begins with a period known as the “prodromal phase,” characterized by high fever, general malaise, dry cough, runny nose (coryza), and conjunctivitis with redness of the eyes. These symptoms often resemble those of the flu. Two to three days after the onset of this phase, small whitish spots appear inside the mouth, known as Koplik spots.
Approximately three to five days after the first symptoms appear, a characteristic rash develops. It is first visible on the face, before spreading to the neck, trunk, and limbs. In some patients, the fever may intensify at the time of the rash, sometimes reaching 104°F (40°C). Respiratory symptoms such as pharyngitis or persistent cough may worsen at the peak of the rash.

Measles is caused by a virus belonging to the Morbillivirus genus of the Paramyxoviridae family. This virus is transmitted exclusively between humans, mainly through the air.
Transmission occurs when an infected person coughs, sneezes, or talks, thereby projecting respiratory droplets into the air. These particles can remain infectious for several hours in the environment. The virus can also be transmitted through direct contact with contaminated surfaces, followed by self-inoculation by touching the mouth, nose, or eyes with the hands.
The virus initially infects immune cells in the respiratory tract, then spreads through the lymphatic system, reaching the spleen and lymph nodes, and returning to the respiratory tract, where it is excreted again.

Measles is one of the most easily transmitted viral diseases from one person to another, affecting mainly unvaccinated individuals. The main risk factor remains lack of immunization. Anyone who has not been vaccinated with two doses of vaccine or who has never had measles is at risk of infection.
Certain populations are particularly vulnerable. The risk of severe complications is significantly higher for infants under one year of age, pregnant women, and immunocompromised patients. Young adults who are partially or unvaccinated are also often affected, particularly when traveling to high-risk areas. International travel is therefore an aggravating factor, especially in regions with low vaccination coverage or during epidemics

Clinical evaluation forms the basis of diagnosis. Measles should be suspected in patients presenting with fever and rash. Koplik spots, small whitish lesions on a red background inside the mouth, are a distinctive sign of this disease, although they are not present in all cases.

Biological confirmation is based on laboratory tests. Specific antibodies (IgM) can be detected in the blood, or PCR can be used to detect viral RNA in nasopharyngeal or urinary samples. In a context of high vaccination coverage, this confirmation is particularly important to avoid misdiagnosis. In Switzerland, all confirmed cases must be reported.

Currently, there is no antiviral treatment for measles. Treatment is primarily symptomatic, aimed at relieving fever, respiratory discomfort, and dehydration. In severe cases or when hospitalization is required, vitamin A administration is recommended to reduce the risk of complications, particularly in children.
In cases of recent exposure, it is sometimes possible to prevent infection by vaccination within 72 hours. This post-exposure strategy helps to limit the progression to a severe form, especially in immunocompromised patients.

Measles is much more than just a viral rash. While most cases resolve within about ten days, the disease can lead to serious complications. The most common complication is pneumonia, which may require hospitalization in intensive care. Other notable complications include ear infections, encephalitis (inflammation of the brain), eye damage, and hepatitis.

Some very rare but serious forms, such as subacute sclerosing panencephalitis (SSPE), can appear several years after infection. This degenerative disease of the central nervous system is always fatal. In addition, measles permanently weakens the immune system, increasing the risk of other infections in the weeks or months following recovery.

Vaccination remains the only reliable way to effectively protect against measles. The combined MMR (measles, mumps, and rubella) vaccine, now often combined with the varicella (chickenpox) vaccine (MMRV), is recommended in Switzerland with a first injection at 9 months, followed by a booster at 12 months. For those who were not vaccinated during childhood, catch-up vaccination is possible at any age. It is particularly important before international travel, especially to high-risk areas. Vaccination coverage of 95% is necessary to prevent the virus from circulating in the population and to avoid epidemics, which is known as herd immunity.
In the event of contact with a person infected with measles, it is sometimes possible to receive the vaccine within 72 hours or immunoglobulins within 6 days, which can prevent or mitigate infection.

In the event of measles, the appropriate response is to consult a physician as soon as the first symptoms appear: fever, rash, cough, and conjunctivitis. If you know you have been in contact with an infected person, or if you have returned from an epidemic area, a medical consultation is essential, especially for unvaccinated or at-risk individuals. If the diagnosis is confirmed, the doctor will alert the cantonal health authorities. The patient must remain in isolation for at least five days after the red spots appear. In all cases, measles requires serious and rapid treatment.

Hôpital de La Tour offers comprehensive care for infectious diseases. The emergency department, open 24/7, provides rapid treatment, particularly in cases of complications such as dehydration or respiratory problems. The most serious cases can be transferred to pediatric or adult intensive care.

How long does measles last?
Generally, between 5 and 10 days without complications. However, the immune system can remain weakened for several weeks.

Why are two doses of the vaccine necessary?
A single dose is not enough to protect everyone. Two doses provide nearly 100% protection.

Is it only a childhood disease?
No. Unvaccinated adults can also contract measles, with more severe forms.