Measles: Concerns and Implications for Dental Professionals

Measles: Cause for Concern and Implications for Dental Professionals

Measles is a highly infectious disease with potentially serious complications and consequences, while an effective killed-virus vaccine was developed to combat it and introduced in the United States (US) in 1963.1Berche P. History of measles. Presse Med 2022;51(3):104149. doi:10.1016/j.lpm.2022.104149.^,2Centers for Disease Control and Prevention. Measles Symptoms and Complications. https://www.cdc.gov/measles/signs-symptoms/index.html#cdc_symptoms_seek_help-complications.^,3The College of Physicians of Philadelphia. History of Vaccines. Measles. Timeline. https://historyofvaccines.org/history/measles/timeline. ^,4Chen SP, Glenn Fennelly. Measles. Medscape. Chief Editor: Steel RW. Updated May 2, 2024. https://emedicine.medscape.com/article/966220-overview. Subsequently, a live attenuated measles, mumps and rubella (MMR) vaccine was introduced, and by 1989 a two-dose schedule was recommended.3The College of Physicians of Philadelphia. History of Vaccines. Measles. Timeline. https://historyofvaccines.org/history/measles/timeline. ^,5Centers for Disease Control and Prevention. Vaccines and Preventable Diseases. MMR and MMRV Vaccine Composition and Dosage. https://www.cdc.gov/vaccines/vpd/mmr/hcp/about.html. This vaccine is 93% effective in preventing measles after one dose and 97% effective after two doses,6Centers for Disease Control and Prevention. Measles Vaccination. https://www.cdc.gov/measles/vaccines/index.html. and vaccination programs globally are believed to have saved 57 million lives between 2000 and 2022.7Katz SL, Hinman AR. Summary and conclusions: measles elimination meeting, 16-17 March 2000. J Infect Dis 2004;189(Suppl 1):S43-7. doi: 10.1086/377696.

An effective vaccine combined with widespread vaccination programs among children has enabled the successful control and prevention of measles in much of the developed world.8World Health Organization. Measles. April 16, 2024. https://www.who.int/news-room/fact-sheets/detail/measles. By 2000, the CDC declared the elimination of measles in the US,8World Health Organization. Measles. April 16, 2024. https://www.who.int/news-room/fact-sheets/detail/measles. based on no new reported cases caused by transmission within the US and a lack of spread of measles. Unfortunately, the success of vaccination programs has led to misperceptions that measles belongs in the distant past and is no longer a danger.9Szinger D, Berki T, Drenjančević I et al. Raising Epidemiological Awareness: Assessment of Measles/MMR Susceptibility in Highly Vaccinated Clusters within the Hungarian and Croatian Population-A Sero-Surveillance Analysis. Vaccines (Basel) 2024;12(5):486. doi: 10.3390/vaccines12050486. There is, however, warranted concern in light of recent outbreaks (defined as 3 or more related cases) and the endemic nature of measles in some areas of the world. It is important that dental professionals understand recent trends, measles transmission, its clinical presentation and prevention.

Measles Outbreaks

Numerous measles outbreaks have occurred in recent years. The largest number of cases in the US since 1992 occurred in 2019, with 22 outbreaks and almost 1300 confirmed cases.10National Foundation for Infectious Diseases. What is Measles? https://www.nfid.org/infectious-disease/measles/. ^,11Patel M, Lee AD, Clemmons NS et al. National Update on Measles Cases and Outbreaks – United States, January 1-October 1, 2019. MMWR Morb Mortal Wkly Rep 2019;68(40):893-6. doi: 10.15585/mmwr.mm6840e2. Of eight outbreaks in communities that were unvaccinated/inadequately vaccinated, two began in 2018 in large, close-knit populations in New York City and New York State.12Zucker JR, Rosen JB, Iwamoto M et al. Consequences of Undervaccination – Measles Outbreak, New York City, 2018-2019. N Engl J Med 2020;382(11):1009-17. doi: 10.1056/NEJMoa1912514. These two outbreaks began with individuals arriving from overseas already infected, and together accounted for 75% of cases in 2019.11Patel M, Lee AD, Clemmons NS et al. National Update on Measles Cases and Outbreaks – United States, January 1-October 1, 2019. MMWR Morb Mortal Wkly Rep 2019;68(40):893-6. doi: 10.15585/mmwr.mm6840e2. Outbreaks have also occurred in Europe, and in areas where measles is endemic including Indonesia, India, Venezuela, Brazil, Africa, and the Middle East.13Newswire. Millions warned about deadly disease. July 3, 2024. https://www.msn.com/en-au/health/other/millions-warned-about-measles-outbreak/ar-BB1pjQnW?&ad=dirN&prod=HP&cmpgn=newinst&annot=false&sameTabLaunch=false&o=APN12425&installSource=direct&browser=Edge&darkMode=false&lang=en_us&ueid=6665C417-8388-42B4-8223-F478027E6DAF&doi=2022-08-31. ^,14World Health Organization. Immunization, vaccines and biologicals: new measles surveillance data for 2019. https://www.who.int/immunization/newsroom/measles-data-2019/en/.

In 2024, as of July 25, 188 cases of measles were reported across 27 jurisdictions in the US, with 123 of these related to 13 outbreaks.15Centers for Disease Control and Prevention. Measles (Rubeola). Measles cases in 2024. https://www.cdc.gov/measles/data-research/index.html. In the United Kingdom, 1,767 confirmed cases of measles were reported during the first half of 2024 (compared to 362 cases for the whole of 2023).16Callingham F, Sharma S. Three early warning signs of measles to look out for in your children as infections rise. Yahoo news. July 4, 2024. https://uk.news.yahoo.com/three-early-warning-signs-measles-090423403.html?&ad=dirN&prod=HP&cmpgn=newinst&annot=false&sameTabLaunch=false&o=APN12425&installSource=direct&ctype=web&browser=Edge&darkMode=false&lang=en_us&ueid=6665C417-8388-42B4-8223-F478027E6DAF&doi=2022-08-31&guccounter=1. Additionally, the Victoria Department of Health in Australia issued an urgent health warning on July 3, 2024 about the risk of a measles outbreak following the return of an individual from overseas while infected.13Newswire. Millions warned about deadly disease. July 3, 2024. https://www.msn.com/en-au/health/other/millions-warned-about-measles-outbreak/ar-BB1pjQnW?&ad=dirN&prod=HP&cmpgn=newinst&annot=false&sameTabLaunch=false&o=APN12425&installSource=direct&browser=Edge&darkMode=false&lang=en_us&ueid=6665C417-8388-42B4-8223-F478027E6DAF&doi=2022-08-31. Most recently, three cases of measles in children were confirmed on July 25, 2024 in three different counties in Minnesota, leading to the health department notifying individuals who were potentially directly exposed and urging unvaccinated individuals to watch for signs of measles.17Minnesota Department of Health. Health officials confirm three measles cases in metro area. News Release, July 25, 2024. https://www.health.state.mn.us/news/pressrel/2024/measles072524.html?&ad=dirN&prod=HP&cmpgn=newinst&annot=false&sameTabLaunch=false&o=APN12425&installSource=direct&browser=Edge&darkMode=false&lang=en_us&ueid=32B6C1C1-0426-40F7-B9B1-602126A48E74&doi=2022-08-31. Travel was not a factor and the three cases were unrelated.

Transmission

Measles is an airborne disease, primarily transmitted by aerosolized droplet nuclei.18Minnesota Department of Health. Measles Clinical Information. https://www.health.state.mn.us/diseases/measles/hcp/clinical.html#NaN. Direct contact, and indirect contact with contaminated surfaces, are minor modes of transmission.19Koenig KL, Alassaf W, Burns MJ. Identify-isolate-inform: A tool for initial detection and management of measles patients in the emergency department. West J Emerg Med 2015;16:212-9. Individuals are infectious from four days prior to onset of the measles rash until four days after the rash develops, and each infected individual infects up to 90% of exposed individuals.10National Foundation for Infectious Diseases. What is Measles? https://www.nfid.org/infectious-disease/measles/. ^,20Centers for Disease Control and Prevention. Clinical overview of measles. https://www.cdc.gov/measles/hcp/clinical-overview/index.html.

Signs and Symptoms of Measles

Signs and symptoms during the prodromal phase of measles develop one to two weeks after infection, with affected individuals typically experiencing increasing fever, a cough, runny nose and/or conjunctivitis.2Centers for Disease Control and Prevention. Measles Symptoms and Complications. https://www.cdc.gov/measles/signs-symptoms/index.html#cdc_symptoms_seek_help-complications.^,7Katz SL, Hinman AR. Summary and conclusions: measles elimination meeting, 16-17 March 2000. J Infect Dis 2004;189(Suppl 1):S43-7. doi: 10.1086/377696. ^,18Minnesota Department of Health. Measles Clinical Information. https://www.health.state.mn.us/diseases/measles/hcp/clinical.html#NaN. Affected individuals may develop a fever as high as 104° F, and may experience visual sensitivity to light and myalgia.4Chen SP, Glenn Fennelly. Measles. Medscape. Chief Editor: Steel RW. Updated May 2, 2024. https://emedicine.medscape.com/article/966220-overview. Two to three days after the onset of symptoms, Koplik spots appear on the buccal mucosa – usually opposite the second molars, presenting as tiny red spots with bluish-white centers that appear to superimpose the spots.19Koenig KL, Alassaf W, Burns MJ. Identify-isolate-inform: A tool for initial detection and management of measles patients in the emergency department. West J Emerg Med 2015;16:212-9. ^,20Centers for Disease Control and Prevention. Clinical overview of measles. https://www.cdc.gov/measles/hcp/clinical-overview/index.html. Koplik spots are pathognomic for measles (specific to measles), and fade within one to two days of the rash developing.2Centers for Disease Control and Prevention. Measles Symptoms and Complications. https://www.cdc.gov/measles/signs-symptoms/index.html#cdc_symptoms_seek_help-complications. (Figure 1)

The measles rash initially develops as flat red spots along the facial hairline before spreading over the neck, torso, limbs, then hands and feet.2Centers for Disease Control and Prevention. Measles Symptoms and Complications. https://www.cdc.gov/measles/signs-symptoms/index.html#cdc_symptoms_seek_help-complications. Within two days of forming, the spots coalesce to form patches and are superimposed with small, raised bumps. The rash usually lasts for between 5 and 7 days before fading. (Figures 2,3) Infected individuals who are immunocompromised may remain rash-free.4Chen SP, Glenn Fennelly. Measles. Medscape. Chief Editor: Steel RW. Updated May 2, 2024. https://emedicine.medscape.com/article/966220-overview.

While breakthrough cases in individuals who are fully vaccinated do occur, and account for around 5% of cases, the disease course is generally milder than for unvaccinated individuals.6Centers for Disease Control and Prevention. Measles Vaccination. https://www.cdc.gov/measles/vaccines/index.html. In addition, individuals vaccinated between 1963 and 1967 received the original measles vaccine, which conferred incomplete immunity, and may contract atypical measles which presents with milder signs and symptoms than typical measles.4Chen SP, Glenn Fennelly. Measles. Medscape. Chief Editor: Steel RW. Updated May 2, 2024. https://emedicine.medscape.com/article/966220-overview.

Measles Complications

Measles complications occur in around 30% of cases, most frequently in children under 5 years-of-age, adults over age 20, and immunocompromised individuals.18Minnesota Department of Health. Measles Clinical Information. https://www.health.state.mn.us/diseases/measles/hcp/clinical.html#NaN. ^,20Centers for Disease Control and Prevention. Clinical overview of measles. https://www.cdc.gov/measles/hcp/clinical-overview/index.html. Complications include otitis media (ear infections), pneumonia, severe breathing issues, severe diarrhea and dehydration.1Berche P. History of measles. Presse Med 2022;51(3):104149. doi:10.1016/j.lpm.2022.104149.^,2Centers for Disease Control and Prevention. Measles Symptoms and Complications. https://www.cdc.gov/measles/signs-symptoms/index.html#cdc_symptoms_seek_help-complications.^,7Katz SL, Hinman AR. Summary and conclusions: measles elimination meeting, 16-17 March 2000. J Infect Dis 2004;189(Suppl 1):S43-7. doi: 10.1086/377696. Less frequent complications include encephalitis, seizures and blindness. Approximately 20% of unvaccinated infected individuals in the US are hospitalized. During pregnancy, measles results in an increased risk of spontaneous abortion, premature birth and low birth-weight babies.21Australian Government. Department of Health and Aged Care. Measles and Pregnancy. https://www.pregnancybirthbaby.org.au/measles-and-pregnancy. Lastly, subacute sclerosing panencephalitis (SSPE) is a rare and fatal long-term complication of measles. This degenerative disease of the central nervous system is believed to be a greater risk for individuals who were under age 2 when infected, and usually develops on average 7 years after experiencing measles.18Minnesota Department of Health. Measles Clinical Information. https://www.health.state.mn.us/diseases/measles/hcp/clinical.html#NaN. ^,20Centers for Disease Control and Prevention. Clinical overview of measles. https://www.cdc.gov/measles/hcp/clinical-overview/index.html.

Among children, common complications include ear infections and pneumonia, affecting ~10% and up to 5% of childhood cases, respectively, in the US.10National Foundation for Infectious Diseases. What is Measles? https://www.nfid.org/infectious-disease/measles/. In addition, 1 in 1,000 infected children develop encephalitis, which can result in convulsions, deafness and intellectual disability. (Figure 4) Up to 3 in 1,000 affected children in the US die, either from respiratory complications associated with pneumonia or neurologic complications of encephalitis.20Centers for Disease Control and Prevention. Clinical overview of measles. https://www.cdc.gov/measles/hcp/clinical-overview/index.html. In countries with low income per capita and/or poor vaccination programs, measles infections and complications are more frequent, with an estimated mortality rate of more than 5% in developing countries.1Berche P. History of measles. Presse Med 2022;51(3):104149. doi:10.1016/j.lpm.2022.104149. (Figure 5)

Vaccination Rates and Herd Immunity

Vaccine hesitancy and refusal within groups is significantly associated with measles outbreaks, as is the importation of measles from areas where it is endemic.22Gupta K, Chen M, Rocker J. Measles: taking steps forward to prevent going backwards. Curr Opin Pediatr 2020;32(3):436-45. doi: 10.1097/MOP.0000000000000895. For example, the 2019 outbreak in New York was associated with importation and also fostered by inadequate immunization caused by misinformation about the safety of the MMR vaccine.23Measles cases and outbreaks: measles cases in 2019. Atlanta: Centers for Disease Control and Prevention, 2019. https://www.cdc.gov/measles/cases-outbreaks.html. In the 2024 outbreak in the US (January to June), 84% of individuals were either confirmed to be unvaccinated or their vaccination status was unknown, and a further 11% had received only one dose of vaccine. Furthermore, the COVID-19 pandemic impacted immunization efforts globally,9Szinger D, Berki T, Drenjančević I et al. Raising Epidemiological Awareness: Assessment of Measles/MMR Susceptibility in Highly Vaccinated Clusters within the Hungarian and Croatian Population-A Sero-Surveillance Analysis. Vaccines (Basel) 2024;12(5):486. doi: 10.3390/vaccines12050486. with 17% of infants missing out on a first dose of the MMR vaccine and vaccination rates in 2022 the lowest since 2008.7Katz SL, Hinman AR. Summary and conclusions: measles elimination meeting, 16-17 March 2000. J Infect Dis 2004;189(Suppl 1):S43-7. doi: 10.1086/377696.

While herd immunity does help to protect individuals who are unvaccinated or inadequately vaccinated, this requires that more than 95% of the ‘herd’, i.e., community, is fully vaccinated. Unfortunately, between 2019-2020 and 2022-2023, MMR vaccination rates among young children in the US decreased from 95.2% to 93.1% and varied within communities.24Centers for Disease Control and Prevention. Measles (Rubeloa). Measles Cases and Outbreaks. https://www.cdc.gov/measles/data-research/index.html. (Figure 6) The most recent data shows that 11 States and the District of Columbia have overall vaccination rates of less than 90%, and only 10 States have an overall vaccination rate of ≥95%.24Centers for Disease Control and Prevention. Measles (Rubeloa). Measles Cases and Outbreaks. https://www.cdc.gov/measles/data-research/index.html.

Figure 6. Vaccination rates in the United States by jurisdiction, 2022-2023.

Additionally, seropositivity rates (immunity) in adults are inadequate, as demonstrated in a recent study. Among adults in Croatia, just 75.7%, 77.5% and 73.3% of individuals ages 20 to 30, 30 to 40 and 40 to 50 years, respectively, were immune to measles.9Szinger D, Berki T, Drenjančević I et al. Raising Epidemiological Awareness: Assessment of Measles/MMR Susceptibility in Highly Vaccinated Clusters within the Hungarian and Croatian Population-A Sero-Surveillance Analysis. Vaccines (Basel) 2024;12(5):486. doi: 10.3390/vaccines12050486. In Italy, where outbreaks are frequent, the reported median age for measles cases in 2017 reached 27 years.25The Economist. Measles is often spread by adults. May 25th 2019. https://www.economist.com/science-and-technology/2019/05/25/measles-is-often-spread-by-adults?utm_medium=cpc.adword.pd&utm_source=google&ppccampaignID=17210591673&ppcadID=&utm_campaign=a.22brand_pmax&utm_content=conversion.direct-response.anonymous&gad_source=5&gclid=EAIaIQobChMIl4WknJ2NhwMVeRitBh1p5QIHEAAYASAAEgKNsPD_BwE&gclsrc=aw.ds.

Implications for Dental Professionals

Screening patients
In addition to a current medical history, patients should be screened for measles by asking them how they are doing and observing them for any indications of illness.26California Dental Association. Dentists must screen patients for measles, other ATDs, before providing treatment. March 20, 2024. https://www.cda.org/newsroom/cal-osha-regulations/dentists-must-screen-patients-for-measles-other-atds-before-providing-treatment/. If a patient is suspected of having measles, it is recommended to ask the patient (or child’s parent/guardian) about their vaccination status and any recent international travel, or contact or proximity with individuals who recently returned or arrived in the US.26California Dental Association. Dentists must screen patients for measles, other ATDs, before providing treatment. March 20, 2024. https://www.cda.org/newsroom/cal-osha-regulations/dentists-must-screen-patients-for-measles-other-atds-before-providing-treatment/. ^,27American Dental Association. Infectious Diseases: Measles. https://www.ada.org/en/resources/practice/practice-management/patients/infectious-diseases-measles. In addition, if patients are suspected (or confirmed) to have measles they should be rescheduled and referred immediately to their primary care facility.28Gordon SC, MacDonald NE, OSAP, The Safest Dental Visit. Managing measles in dental practice: a forgotten foe makes a comeback. J Am Dent Assoc 2015;146:558-60. If measles is present in the community it is also recommended that patients be asked to provide written documentation confirming that they are vaccinated against measles; infected individuals should be isolated while they are infectious.26California Dental Association. Dentists must screen patients for measles, other ATDs, before providing treatment. March 20, 2024. https://www.cda.org/newsroom/cal-osha-regulations/dentists-must-screen-patients-for-measles-other-atds-before-providing-treatment/. DHCP should receive training on screening patients, and having and following a facility written policy and procedure for the dental office for screening patients for aerosol-transmitted diseases can be recommended.

Reporting measles cases
Healthcare personnel, including DHCP, are required to report suspected/confirmed cases of measles to their State Department of Health.27American Dental Association. Infectious Diseases: Measles. https://www.ada.org/en/resources/practice/practice-management/patients/infectious-diseases-measles. ^,28Gordon SC, MacDonald NE, OSAP, The Safest Dental Visit. Managing measles in dental practice: a forgotten foe makes a comeback. J Am Dent Assoc 2015;146:558-60.

Promoting vaccination
Dental professionals have an opportunity to educate patients and parents, and to encourage vaccine uptake, by providing accurate information and, if necessary, quelling concerns generated by misinformation and disinformation.

The CDC recommends that children receive a first dose of MMR vaccine or MMRV vaccine between 12 and 15 months of age, followed by a second dose between age 4 and 6 years.29Centers for Disease Control and Prevention. Vaccines and Preventable Disease. Measles, Mumps, and Rubella (MMR) Vaccination: What Everyone Should Know. https://www.cdc.gov/vaccines/vpd/mmr/public/index.html. If travelling overseas, children 12 months and older should receive two doses. In children age 12 months through age 12 years only, the MMRV vaccine may be given in place of the MMR vaccine to additionally provide protection against varicella (chickenpox). If children 6 to 11 months old will be traveling, it is recommended that they receive one dose of the MMR vaccine. In addition, students at post-high school educational institutions who do not have presumptive evidence of immunity need two doses of MMR vaccine, separated by at least 28 days. Adults without presumptive evidence of immunity should receive a single dose of MMR vaccine, unless at greater risk – in which case a second dose is recommended. As with all vaccines, individuals with contraindications to the MMR vaccine (or MMRV) should not receive these.

Dental Healthcare personnel (DHCP)
In accordance with recommendations from the Advisory Committee on Immunization Practices (ACIP), DHCP should have documentation showing evidence of immunity against measles.27American Dental Association. Infectious Diseases: Measles. https://www.ada.org/en/resources/practice/practice-management/patients/infectious-diseases-measles. ACIP recommends two doses of the MMR vaccination, 28 days apart, for all DHCP who do not have evidence of immunity.29Centers for Disease Control and Prevention. Vaccines and Preventable Disease. Measles, Mumps, and Rubella (MMR) Vaccination: What Everyone Should Know. https://www.cdc.gov/vaccines/vpd/mmr/public/index.html. In addition, a third dose is recommended during an outbreak for at-risk DHCP previously vaccinated. If exposure to measles occurs or is suspected, it is recommended that DHCP who are not known to be immune be offered and receive appropriate post-exposure prophylaxis through their primary care team.

Standard precautions in the dental setting are always needed for infection control and prevention. Airborne precautions should also be instituted if a patient arrives who is suspected/confirmed with measles, as well as when measles is present in the local community. Airborne precautions require the use of a fit-tested N95 respirator (or an equivalent respirator) by DHCP (even if immunized) in accordance with regulations and recommendations.27American Dental Association. Infectious Diseases: Measles. https://www.ada.org/en/resources/practice/practice-management/patients/infectious-diseases-measles.

Conclusions

Recent outbreaks in the US and elsewhere highlight the risk of measles elimination being reversed, while in other areas measles remains endemic and an estimated 136,000 deaths occur annually worldwide.1Berche P. History of measles. Presse Med 2022;51(3):104149. doi:10.1016/j.lpm.2022.104149.^,8World Health Organization. Measles. April 16, 2024. https://www.who.int/news-room/fact-sheets/detail/measles. Furthermore, given that measles is more infectious than any other vaccine-preventable disease, herd immunity is particularly fragile in the face of imported cases, vaccine hesitancy and refusal.30Feemster KA, Szipszky C. Resurgence of measles in the United States: how did we get here? Curr Opin Pediatr 2020;32(1):139-44. doi: 10.1097/MOP.0000000000000845. Several outbreaks have occurred recently in the United States, causing considerable human and resource costs. It is important that dental professionals understand current trends and are able to screen and identify signs and symptoms of measles, enabling appropriate actions including patient referral to primary care teams, rescheduling of patients if required and the use of transmission-based precautions. Vaccine promotion has been shown to be effective in improving vaccination rates when collaboration exists between communities and health departments.12Zucker JR, Rosen JB, Iwamoto M et al. Consequences of Undervaccination – Measles Outbreak, New York City, 2018-2019. N Engl J Med 2020;382(11):1009-17. doi: 10.1056/NEJMoa1912514. Dental professionals can also play an important role in providing patients with proper information, debunking misinformation and disinformation, and encouraging vaccination and protection against measles.

References

• 1.Berche P. History of measles. Presse Med 2022;51(3):104149. doi:10.1016/j.lpm.2022.104149.
• 2.Centers for Disease Control and Prevention. Measles Symptoms and Complications. https://www.cdc.gov/measles/signs-symptoms/index.html#cdc_symptoms_seek_help-complications.
• 3.The College of Physicians of Philadelphia. History of Vaccines. Measles. Timeline. https://historyofvaccines.org/history/measles/timeline.
• 4.Chen SP, Glenn Fennelly. Measles. Medscape. Chief Editor: Steel RW. Updated May 2, 2024. https://emedicine.medscape.com/article/966220-overview.
• 5.Centers for Disease Control and Prevention. Vaccines and Preventable Diseases. MMR and MMRV Vaccine Composition and Dosage. https://www.cdc.gov/vaccines/vpd/mmr/hcp/about.html.
• 6.Centers for Disease Control and Prevention. Measles Vaccination. https://www.cdc.gov/measles/vaccines/index.html.
• 7.Katz SL, Hinman AR. Summary and conclusions: measles elimination meeting, 16-17 March 2000. J Infect Dis 2004;189(Suppl 1):S43-7. doi: 10.1086/377696.
• 8.World Health Organization. Measles. April 16, 2024. https://www.who.int/news-room/fact-sheets/detail/measles.
• 9.Szinger D, Berki T, Drenjančević I et al. Raising Epidemiological Awareness: Assessment of Measles/MMR Susceptibility in Highly Vaccinated Clusters within the Hungarian and Croatian Population-A Sero-Surveillance Analysis. Vaccines (Basel) 2024;12(5):486. doi: 10.3390/vaccines12050486.
• 10.National Foundation for Infectious Diseases. What is Measles? https://www.nfid.org/infectious-disease/measles/.
• 11.Patel M, Lee AD, Clemmons NS et al. National Update on Measles Cases and Outbreaks – United States, January 1-October 1, 2019. MMWR Morb Mortal Wkly Rep 2019;68(40):893-6. doi: 10.15585/mmwr.mm6840e2.
• 12.Zucker JR, Rosen JB, Iwamoto M et al. Consequences of Undervaccination – Measles Outbreak, New York City, 2018-2019. N Engl J Med 2020;382(11):1009-17. doi: 10.1056/NEJMoa1912514.
• 13.Newswire. Millions warned about deadly disease. July 3, 2024. https://www.msn.com/en-au/health/other/millions-warned-about-measles-outbreak/ar-BB1pjQnW?&ad=dirN&prod=HP&cmpgn=newinst&annot=false&sameTabLaunch=false&o=APN12425&installSource=direct&browser=Edge&darkMode=false&lang=en_us&ueid=6665C417-8388-42B4-8223-F478027E6DAF&doi=2022-08-31.
• 14.World Health Organization. Immunization, vaccines and biologicals: new measles surveillance data for 2019. https://www.who.int/immunization/newsroom/measles-data-2019/en/.
• 15.Centers for Disease Control and Prevention. Measles (Rubeola). Measles cases in 2024. https://www.cdc.gov/measles/data-research/index.html.
• 16.Callingham F, Sharma S. Three early warning signs of measles to look out for in your children as infections rise. Yahoo news. July 4, 2024. https://uk.news.yahoo.com/three-early-warning-signs-measles-090423403.html?&ad=dirN&prod=HP&cmpgn=newinst&annot=false&sameTabLaunch=false&o=APN12425&installSource=direct&ctype=web&browser=Edge&darkMode=false&lang=en_us&ueid=6665C417-8388-42B4-8223-F478027E6DAF&doi=2022-08-31&guccounter=1.
• 17.Minnesota Department of Health. Health officials confirm three measles cases in metro area. News Release, July 25, 2024. https://www.health.state.mn.us/news/pressrel/2024/measles072524.html?&ad=dirN&prod=HP&cmpgn=newinst&annot=false&sameTabLaunch=false&o=APN12425&installSource=direct&browser=Edge&darkMode=false&lang=en_us&ueid=32B6C1C1-0426-40F7-B9B1-602126A48E74&doi=2022-08-31.
• 18.Minnesota Department of Health. Measles Clinical Information. https://www.health.state.mn.us/diseases/measles/hcp/clinical.html#NaN.
• 19.Koenig KL, Alassaf W, Burns MJ. Identify-isolate-inform: A tool for initial detection and management of measles patients in the emergency department. West J Emerg Med 2015;16:212-9.
• 20.Centers for Disease Control and Prevention. Clinical overview of measles. https://www.cdc.gov/measles/hcp/clinical-overview/index.html.
• 21.Australian Government. Department of Health and Aged Care. Measles and Pregnancy. https://www.pregnancybirthbaby.org.au/measles-and-pregnancy.
• 22.Gupta K, Chen M, Rocker J. Measles: taking steps forward to prevent going backwards. Curr Opin Pediatr 2020;32(3):436-45. doi: 10.1097/MOP.0000000000000895.
• 23.Measles cases and outbreaks: measles cases in 2019. Atlanta: Centers for Disease Control and Prevention, 2019. https://www.cdc.gov/measles/cases-outbreaks.html.
• 24.Centers for Disease Control and Prevention. Measles (Rubeloa). Measles Cases and Outbreaks. https://www.cdc.gov/measles/data-research/index.html.
• 25.The Economist. Measles is often spread by adults. May 25th 2019. https://www.economist.com/science-and-technology/2019/05/25/measles-is-often-spread-by-adults?utm_medium=cpc.adword.pd&utm_source=google&ppccampaignID=17210591673&ppcadID=&utm_campaign=a.22brand_pmax&utm_content=conversion.direct-response.anonymous&gad_source=5&gclid=EAIaIQobChMIl4WknJ2NhwMVeRitBh1p5QIHEAAYASAAEgKNsPD_BwE&gclsrc=aw.ds.
• 26.California Dental Association. Dentists must screen patients for measles, other ATDs, before providing treatment. March 20, 2024. https://www.cda.org/newsroom/cal-osha-regulations/dentists-must-screen-patients-for-measles-other-atds-before-providing-treatment/.
• 27.American Dental Association. Infectious Diseases: Measles. https://www.ada.org/en/resources/practice/practice-management/patients/infectious-diseases-measles.
• 28.Gordon SC, MacDonald NE, OSAP, The Safest Dental Visit. Managing measles in dental practice: a forgotten foe makes a comeback. J Am Dent Assoc 2015;146:558-60.
• 29.Centers for Disease Control and Prevention. Vaccines and Preventable Disease. Measles, Mumps, and Rubella (MMR) Vaccination: What Everyone Should Know. https://www.cdc.gov/vaccines/vpd/mmr/public/index.html.
• 30.Feemster KA, Szipszky C. Resurgence of measles in the United States: how did we get here? Curr Opin Pediatr 2020;32(1):139-44. doi: 10.1097/MOP.0000000000000845.