Would you recognize measles? Canadian docs need to get reacquainted

Canada has seen four cases of measles in the first four months of 2023. Before diagnosis, the patients had multiple interactions with healthcare facilities, prompting fears of an outbreak and suggesting that the diagnosis was not immediately, or easily, made. “We need to get measles up on clinicians’ radar,” said Dr. Vinita Dubey, Toronto’s associate medical officer of health. The most recent cases were in April, one in Halifax and one in Toronto. It was the second case for Toronto in 2023. The Halifax patient visited the IWK Health Centre Emergency Department and a medical clinic before diagnosis. The Toronto patient visited a walk-in clinic and the emergency departments at both Toronto Western and Toronto General hospitals. Both cases in Toronto involved adults who returned from trips to South-East Asia. The incubation period for measles is seven to 21 days, with symptoms appearing after 10 to 14 days. A patient may present with fever, a runny nose, and, after a few days, a maculopapular rash. Conjunctivitis, a cough and diarrhea may also be present. The rash consists of deep, flat red lesions that appear on the face and then spread down the body, lasting up to a week. The patient may have discoloured and peeling skin after the rash leaves. The rash may be harder to detect on patients with darker skin. Small white spots (Koplik spots) may appear inside the mouth. “If someone had a travel history in the past three weeks and developed a fever, rash or was not feeling well, you have to consider measles,” Dr. Dubey said. Testing for measles includes a urine test, a blood test and a nasopharyngeal or throat swab. Dr. Dubey suggests that physicians work with the local public health unit to ensure ordering the appropriate test. There’s no specific treatment for measles, beyond providing supportive medical care and watching for complications such as ear infections, encephalitis or bacterial infection. Complications of measles infection occur in about 10% of cases, according to the Canadian Immunization Guide. Children are at higher risk for further infections, including pneumonia. People who are pregnant can suffer premature labour, miscarriage or give birth to a baby with a low birth weight. Containing the spread People with measles are considered infectious from four days prior to four days after rash onset. This means people can spread the disease before they know that they have it. If possible, encourage patients who suspect they or their child have measles to call before coming to the clinic. Arrange a time to see them when the waiting room won’t be packed and pick an examination room with negative air flow or good ventilation. “It’s really important to prevent the possible spread to the most vulnerable, infants less than one who have not been vaccinated, for example,” Dr. Dubey said. Measles can be transmitted from one person to another through the airborne route, respiratory droplets or with direct contact with throat or nasal secretions. It is highly communicable, with more than 90% secondary rate attacks among susceptible people, according to the Canadian Immunization Guide. The National Advisory Committee on Immunization has information on measles post-exposure prophylaxis. Read: ‘Catch up with confidence:’ National Immunization Awareness Week is focusing on routine jabs Vaccination Despite widespread vaccination in Canada, there are people who could still be susceptible to measles. A study presented at the 2023 Canadian Immunization Conference suggested that only 83.4% of Ontarians had enough antibodies to be sufficiently protected from measles. Archchun Ariyarajah, a PhD candidate from the University of Toronto, and colleagues studied measles IgG antibodies in 349,706 people in Ontario. They concluded that since the percentage of people protected from measles in the general population falls below the 95% needed for herd immunity, the disease could become endemic again in younger populations. The level of protection differed for different ages, with only those born before 1970 reaching herd immunity levels, with 94.9% having sufficient antibody levels to be considered protected from measles. The study supports previous Canada-wide work that showed measles immunity levels in the Canadian population falling below herd immunity levels. Unless they have proof of immunity, consider giving one dose of measles, mumps and rubella (MMR) vaccine (unless there are contraindications, such as pregnancy) to people who may come in contact with measles. This includes: healthcare workers, people travelling outside Canada students in university or college military personnel The Canadian Immunization Guide has a chart to identify which people are considered immune to measles. This includes people who are travelling outside of Canada who’ve had two doses of vaccine (or one dose if born before 1970). Anyone with an insufficient vaccination record can be given an MMR vaccine. There is no risk of adverse events with repeated vaccination. Not having a family physician is a barrier to vaccination, noted Shelley Bolotin, director of the Dalla Lana School of Public Health’s centre for vaccine preventable diseases in Toronto. This means other healthcare professionals need to encourage immunization. “Pharmacists are very well-provisioned to counsel adults on vaccinations,” Bolotin said. Read: A shot prevents frailty: Reframe your message about adult vaccinations, experts say Children age six months should get early vaccine if travelling Children aged six to 12 months travelling to countries where measles is endemic should get an MMR vaccine before they go, Dr. Dubey said. While antibodies against measles are given to infants from their vaccinated mothers, a new study suggests infants aged four months and up don’t have enough antibody protection against measles. Researchers studied antibody levels of 257 full-term infants under 12 months old who were admitted to the Hospital for Sick Children in Toronto with a non-infectious disease. In total, 68.5% of the infants did not have sufficient antibody levels to fight off a measles infection. The risk of having insufficient antibodies more than doubled with each month of life. The study was presented by James Wright of Public Health Ontario at the 2023 Canadian Immunization Conference. The findings are in keeping with a preliminary study conducted by the same team, published in Pediatrics in 2019. The context of these new studies is in an era where a mother’s antibodies against measles are from vaccination. Previous studies had been conducted in areas or time periods when measles had been in the population, and mother’s immunity was reached through either infection or immunization. Children usually get their first MMR dose at 12 months, but it’s safe for them to receive it anytime after six months. Any dose given before 12 months should be considered dose zero instead of dose one, said Bolotin. Doses given before 12 months don’t promote sufficient antibody protection to last until the second MMR dose, given to four to five-year-olds. Increased numbers of cases in the Americas Ontario’s chief medical officer of health issued a memo in February 2023 asking physicians to consider measles as a differential diagnosis, especially in people returning from travel. The memo was sparked by a Feb. 8 epidemiological alert from the Pan American Health Organization and the World Health Organization (WHO) regional office for the Americas. Their alert was due to decline in vaccination coverage for the first and second doses of the MMR vaccine, combined with reported cases of measles. The WHO region of the Americas was declared measles-free in 2016, but cases were reported in other regions, and soon it lost its measles elimination status. An outbreak in Brazil began in June 2022. In 2021 and 2022 there were also cases reported in Argentina, Canada, Ecuador, French Guiana and the U.S. A measles outbreak in Kentucky in February 2023 prompted Health Canada to warn attendees of a religious gathering there to be on the lookout for symptoms. Currently, public Health Agency of Canada gives its own nation a level one travel warning for measles, also applicable for the entire globe. Level one means practice health precautions, which, in this case means to get vaccinated, wash your hands and practice proper cough and sneeze etiquette. Data from UNICEF and the WHO suggest that more than 2.7 million in the Americas don’t have a complete vaccination schedule, and are therefore susceptible to vaccine-preventable diseases. Read: What is the real impact of routine childhood immunization on reducing preventable diseases? Other vaccine-preventable diseases The WHO announced on April 24 that it is promoting “The Big Catch-up,” a push to get immunization goals back on track after being disrupted by the pandemic. More than 40 million children missed measles vaccinations in 2021 alone, the WHO reports. “Measles is usually a warning signal, or a tracer,” said Dr. Folake Olayinka, the immunization technical lead at the global health bureau of the United States Agency of International Development (USAID) in Washington, D.C. “These other diseases are on the trail behind it.” Dr. Olayinka spoke at the Canadian Immunization Conference. The Canadian Immunization Conference, organized by the Public Health Agency of Canada and held from April 25 to 27 in Ottawa. Read: U.S. approves first vaccine for RSV after decades of attempts

Would you recognize measles? Canadian docs need to get reacquainted

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