Understanding measles and the role of vaccination

Understanding measles and the role of vaccination

With measles cases increasing in Canada and around the world, it is important for physicians to understand the disease and the role of vaccination against measles. Two practice articles inCMAJ(Journal of the Canadian Medical Association) https://www.cmaj.ca/lookup/doi/10.1503/cmaj.240371Provide a brief overview of this highly contagious disease. Many physicians may not have direct experience diagnosing and treating measles since Canada achieved measles elimination status in 1998.

The increase in measles activity worldwide and in Canada is a reminder of the importance of vaccination. Routine childhood vaccinations, including measles, that were missed during the COVID-19 pandemic should be urgently caught up. Physicians should also be alert for measles when evaluating patients, particularly those with a travel history or those who may have been infected in local outbreaks.”

Dr. Sarah Wilson, author, physician at Public Health Ontario

Measles is one of the most contagious respiratory diseases. People with measles develop fever, cough, runny nose, and conjunctivitis. About 4 days later, a rash may appear that begins on the face and spreads throughout the body. Complications due to measles infection are reported in 30% of cases. These can include ear infections, pneumonia, pregnancy complications, and neurological complications, including encephalitis. Measles can also cause a temporary secondary immune deficiency. Most cases of measles in Canada occur in unvaccinated people, particularly children.

Given the contagiousness of measles, healthcare providers should preemptively contact healthcare facilities when referring suspected cases for assessment or investigation to ensure that appropriate infection prevention and control measures are taken to avoid endangering other patients and staff.

Despite effective vaccination programs, measles outbreaks are increasing, highlighting the need for increased vaccination efforts. TheCanadian vaccination guiderecommends administration of the measles, mumps and rubella (MMR) vaccine to all individuals in Canada, with specific dosing schedules and catch-up recommendations.

During travel or outbreaks, MMR vaccination may occur beyond standard schedules, with guidelines for accelerated vaccination and post-exposure prophylaxis. Adults without measles immunity or proof of vaccination may receive 1-2 doses of the MMR vaccine depending on age, travel history, and risk factors. The MMR vaccine is safe and effective. However, individuals with immunocompromised conditions must be carefully evaluated.

"Measles is highly contagious and is making a comeback worldwide. The measles vaccine is effective and safe. However, immunocompromised or pregnant people cannot receive it. Herd immunity through mass vaccination is therefore crucial. Our article summarizes who should receive it." Vaccination occurs outside of the typically recommended vaccination schedule, particularly in children who are particularly vulnerable to complications from measles. We also recommend adults receive one or more doses of the vaccine depending on their year of birth, travel or location in an outbreak-affected area and occupation,” says Dr. Samira Jeimy, Program Director and Assistant Professor of Clinical Immunology and Allergy, Western University, London, Ontario.

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