Measles: Importance Of Vaccination
Measles is an extremely infectious and highly contagious viral disease that affects all ages. Despite the availability of a vaccine, more than 140,000 deaths occurred globally in 2018, mostly in children under five. Before measles vaccinations were available, measles epidemics occurred every 2 to 3 years. The WHO also reported that the vaccine has decreased measles deaths by 73% and prevented 23.2 million deaths from occurring in 2018.
What are measles?
Measles, also known as rubeola, is one of the most contagious infectious diseases known. The measles virus is from the paramyxovirus family.
The measles virus is transmitted through respiratory droplets that can remain contagious in the air and on surfaces for up to 2 hours.
The virus first infects the respiratory system before spreading throughout the body. Within the first two days, viral replication occurs in the trachea and bronchial tubes of the lung. After 4 days, the virus travels through the lymphatic system to infect other parts of the body.
Up to 90% of people who are unvaccinated or who have never contracted the disease before are prone to developing measles after coming into contact with someone with the disease.
Someone infected with measles is contagious several days before and after the onset of rashes and the infection usually clear between 7 to 10 days.
Symptoms of measles
Symptoms may take up to 10 to 14 days after infection to surface. They include:
- Flu symptoms e.g. runny nose, sneezing and cough
- Red and sore eyes
- High fever
- Small greyish-white spots on the inside of the cheeks (Koplik spots) with a sore throat
- Light sensitivity
- Eye inflammation (conjunctivitis)
- Red-brown blotchy rash on the head and upper neck before spreading to the rest of the body
- Mild itchy rash that appears after 3 to 5 days of other symptoms that start at the sides of the neck as irregular red patches that slowly become bumpy before spreading to the rest of the body. Rashes last for about 5 days before fading.
Measles can also cause swelling of the lymph nodes, alongside diarrhoea and vomiting.
Blood tests are also conducted to trace infections in some communities to ensure that transmissibility can be accounted for to limit the spread of disease.
Severe measles is most common in children under the age of 5 who are malnourished and in adults above the age of 30. Patients with HIV or AIDS are also more susceptible to infection.
Ear and brain infections are very common in children infected with measles. Swelling of the brain (measles encephalitis) occurs in 1 in 1000 children, which can lead to uncontrolled muscle spasms along with altered consciousness (convulsions), coma, deafness, and intellectual disabilities. Recovery usually takes a week but can also lead to brain damage if left untreated.
Pneumonia is another complication caused by measles that is the usual cause of death in infants. In individuals with cellular immunity deficiency, giant cell pneumonia is a common and fatal complication that occurs because of complications.
Liver inflammation and diarrhoea may occur concurrently during an active measles infection.
Immunocompetent individuals are predisposed to secondary opportunistic infections after being infected with measles. Wild-type measles, however, can induce an immune response that confers lifelong immunity after recovery.
Prevention of measles
Measles can be prevented by taking the measles, mumps and rubella (MMR) vaccine that is usually given first between 12 months of age and a second dose between 15 to 18 months (Singapore) or 4 through 6 years (USA). The vaccine is preventive when administered within 3 days of exposure and may cause mild fever or rashes.
Human immunoglobulin is a special concentration of antibodies that gives short-term but immediate protection against measles administered within 6 days of exposure. It is usually given to:
- Infants aged between 6 months to 1 year
- Pregnant women
- Immunocompromised patients who cannot take the vaccine
- Infants born to mothers without measles immunity
Treatment for measles
There is no specific antiviral treatment for measles. In children who are malnourished or who have a vitamin A deficiency, Vitamin A supplementation oral tablets are prescribed in two doses, given 24 hours apart. This helps to restore low vitamin A levels and prevents blindness.
Ibuprofen or acetaminophen (paracetamol) are also given for patients who present with fever. Patients who are severely dehydrated and febrile are also treated with intravenous rehydration or given oral rehydration to replace fluids and electrolytes lost through diarrhoea.
Secondary infections such as bacterial pneumonia are treated with antibiotics.
Measles is a highly infectious acute communicable disease which warrants high levels of immunisation. If not treated properly, serious complications including death can occur. Immunisation can greatly help to reduce measles death from this vaccine-preventable disease.
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Speaker: Dr Lee Guan Huei 李冠辉, Senior Consultant, Gastroenterology, NUH Sponsors/Organising parties: 365 Cancer Prevention Society (365CPS), Singapore National University Hospital (NUH), Singapore National University