25/03/2024

PAHO briefs health professionals on measles as cases increase in the Americas

By PAHO

A webinar organized by the Pan American Health Organization (PAHO) this week updated medical, nursing, laboratory, and epidemiology personnel on the clinical, surveillance, and vaccination aspects of measles. The webinar was organized following a recent uptick in cases in the Americas.

As of March 16, 2024, a total of 92 confirmed cases have been reported in seven countries of the region - the vast majority in the United States and Canada, but representing  a 28% increase compared to the total number of cases reported in 2023.

"Measles cases are increasing everywhere," PAHO Regional Immunization Advisor Dr. Gloria Rey warned.  Globally, cases reported to the World Health Organization (WHO) increased by 79% in 2023 compared to 2022, with more countries worldwide (51) experiencing large outbreaks. For Rey, the early increase in cases this year suggests that the situation could intensify over the coming months.

Despite the existence of an effective vaccine against measles, cases and deaths from the disease continue to occur worldwide. In 2022, an estimated 136,216 measles-related deaths were reported, representing a 43% increase compared to the previous year.

The Americas is at risk of more cases and outbreaks due to the decline in vaccination coverage. In 2024, 70% of measles cases occurred in those under the age of 10 years, and 78% of cases were contracted outside their countries or were due to imported cases.

For years, coverage with the first dose of the measles, mumps, and rubella (MMR) vaccine remained above 90% in the Americas, but in 2019, it dropped to 87%, reaching its lowest point in 2022 at 85%, well below PAHO's recommended ideal of at least 95% to prevent outbreaks.

"The COVID-19 pandemic exacerbated the downward trend in measles vaccination coverage, which has not yet recovered and remains stagnant," Desiree Pastor, Regional Immunization Advisor at PAHO, said. 

On an encouraging note, Dr. Pastor pointed out that despite the pandemic, countries in the region continued to implement vaccination campaigns, reaching more than 36 million children aged 1 to 12 years between 2021 and 2023.

During the webinar, Dr. Tracy Evans-Gilbert, Clinical Pediatrics expert at West Virginia University and member of the Regional Commission for Monitoring and Sustaining the Elimination of Measles, Rubella, and Congenital Rubella Syndrome (CRS) in the Americas, provided a briefing on the clinical aspects of measles and rubella, highlighting their differences from other diseases such as dengue. Her presentation aimed to familiarize healthcare workers with measles so that they can recognize, report, and address it promptly.

Dr. Evans-Gilbert emphasized that measles, in addition to fever and rash, often produces respiratory symptoms such as cough and runny nose, which are not observed in dengue, for example. The virus is also highly contagious, with an infected person being capable of infecting between 12 and 18 people at once. It is transmitted through respiratory droplets when an infected person speaks, coughs, or sneezes and can remain active in the air for up to 2 hours, spreading within a radius of 2 to 4 meters.

Faced with the possible arrival of more imported measles cases in the region, PAHO advisors highlighted the importance of implementing essential prevention and control measures. This includes swift and intensified vaccination in high-risk areas, enhanced epidemiological surveillance, including active case searches in the field and a focus on areas such as border municipalities, and a rapid response to outbreaks, requiring trained teams and protocols to identify and manage cases promptly.

In January this year, PAHO issued an alert urging countries in the Americas to strengthen surveillance and increase vaccination efforts, given the rise in measles cases worldwide. Since March 2023, the Organization has made two free self-learning courses available on its virtual campus aimed at improving measles surveillance and outbreak response.