Navigating the complexities of measles control in primary care
Measles presents unique challenges that demand proactive measures for containment. Below are some key challenges associated with measles control, along with suggested strategies for family physicians to approach those challenges.
1. Highly Infectious Nature of Measles: The measles virus is the most known infectious virus.1 Achieving vaccination coverage of over 95% within the community, especially among children, is essential to control the extensive transmission of the virus. The COVID-19 pandemic has resulted in a gap in vaccination globally. In the current landscape and with misinformation about measles-containing vaccines, employing persuasive communication techniques, such as motivational interviewing, while addressing parental concerns about vaccine safety is essential for increasing vaccination uptake.2
2. Misdiagnosis in Early Stages of Measles: Initial symptoms of measles mimic those of common respiratory illnesses, leading to potential under-recognition by both patients and healthcare providers. In addition, due to the rarity of measles cases in the last two decades, physicians may overlook its possibility, resulting in delayed testing and diagnosis. It is imperative to suspect measles in patients exhibiting fever, respiratory symptoms, and conjunctivitis, with or without rash, particularly in those who lack documented vaccination with two doses of MMR or MMRV and recent travel outside of Canada.3
3. Testing Challenges: To ensure timely identification and containment of measles, it is imperative to conduct serological, nasopharyngeal swabs (NPS), and urine PCR tests simultaneously when suspicion arises.3,4 Clinical specimens should be obtained from suspected patients during their initial contact with healthcare providers. Serology tests measuring IgM and IgG levels may yield misleading interpretations when used alone. During the early stages of the disease, IgM and IgG levels may not reach diagnostic thresholds, leading to false negative results. Furthermore, in individuals previously vaccinated against measles, other viral infections may elevate measles IgM levels, resulting in a false positive result. Although PCR tests necessitate more time for completion, they can complement serological findings, enhancing diagnostic accuracy. That is why all the three tests should be done simultaneously.
4. Inadequate Infection Control Knowledge Among Clinicians: Limited awareness of measles infection prevention and control measures among healthcare providers, in addition to the disease's high infectiousness, airborne nature, and the virus's lasting in the air for up to two hours, can contribute to nosocomial transmission. Utilizing available resources and tools4,5 can enhance clinician preparedness and confidence in potential measles encounters in primary care offices. Patients should be advised to call before visiting the office to minimize exposure to others. Upon arrival, they should be offered a medical mask and isolated immediately in a single room with a closed door, ideally with negative pressure. Clinicians should take respiratory precautions and use N95 masks during the encounter. While most patients can receive care in the office, if a referral to an emergency department is necessary, communication with the facility should occur before the arrival of the patient to prevent transmission to other patients in the waiting room.
5. Brief Window of Opportunity for Post-Exposure Prophylaxis in Exposed Individuals: Prompt intervention following measles exposure is critical, as the window for preventive measures is limited to six days. Administering the measles vaccine or immunoglobulin promptly, considering individual circumstances, can significantly reduce the risk of disease manifestation in susceptible individuals.6 Family physicians should report all suspected measles cases to the local public health agencies immediately without waiting for diagnostic test results to expedite identifying the susceptible contacts.
6. Lack of Effective Antiviral Treatments: There is no antiviral treatment for measles. Most people do not require hospitalization, but they need isolation at home until 4 days after the rash first appears to limit the spread of the virus. Treatment should be directed toward relieving symptoms, including fever and dehydration, and managing complications (e.g. pneumonia and otitis media) if they happen.7 Vitamin A deficiency is linked to higher complications with measles, and measles may precipitate a vitamin A deficiency. Therefore, family physicians may consider giving two doses of vitamin A supplements immediately on diagnosis and repeating the next day to all children diagnosed with measles: 50000 IU to infants aged <6 months, 100000 IU to children aged 6-11 months, and 200000 IU to children >12 months.8
Addressing these challenges through tailored strategies and heightened awareness among healthcare providers and communities is essential for effective measles prevention, control and treatment.
Dr. Mehdi Aloosh is a public health and preventive medicine specialist and family physician with two decades of clinical and academic experience internationally and in Canada. Currently, he serves as the Medical Officer of Health for Windsor and Essex County, Ontario. In addition to his public health leadership role and family medicine practice, he is an assistant professor in the Department of Health Research Methods, Evidence, and impact at McMaster University.
References
1. Durrheim DN, Andrus JK, Tabassum S, Bashour H, Githanga D, Pfaff G. A dangerous measles future looms beyond the COVID-19 pandemic. Nature Medicine. 2021;27(3):360-361.O’Leary ST, Opel DJ, Cataldi JR, et al. Strategies for Improving Vaccine Communication and Uptake. Pediatrics. 2024;153(3).
2. O’Leary ST, Opel DJ, Cataldi JR, et al. Strategies for Improving Vaccine Communication and Uptake. Pediatrics. 2024;153(3).
3. Public Health Agency of Canada. Measles: For health professionals. 2024; https://www.canada.ca/en/public-health/services/diseases/measles/health-professionals-measles.html. Accessed March 10, 2024.
4. Ontario Agency for Health Protection and Promotion (Public Health Ontario). Measles: Information for Health Care Providers 2024; https://www.publichealthontario.ca/-/media/Documents/M/24/measles-information-health-care-providers.pdf?rev=739ee7f9b7304584b21bfe82dbe9043f&sc_lang=en. Accessed March 10, 2024.
5. Ontario Agency for Health Protection and Promotion (Public Health Ontario), Provincial Infectious Diseases Advisory Committee. Best practices for environmental cleaning for infection prevention and control [Internet]. 3rd ed. Toronto, ON: Queen’s Printer for Ontario; 2018. Available from: https://www.publichealthontario.ca/-/media/documents/B/2018/bp-environmental-cleaning.pdf. Accessed March 10, 2024.
6. Public Health Agency of Canada. Measles vaccines: Canadian Immunization Guide. 2023; https://www.canada.ca/en/public-health/services/publications/healthy-living/canadian-immunization-guide-part-4-active-vaccines/page-12-measles-vaccine.html#pep. Accessed March 10, 2024.
7. Rota PA, Moss WJ, Takeda M, de Swart RL, Thompson KM, Goodson JL. Measles. Nature Reviews Disease Primers. 2016;2(1):16049.
8. World Health Organization. Measles vaccines: WHO position paper, April 2017–Recommendations. Vaccine. 2019;37(2):219-222.