In a concerning development, the US Centers for Disease Control and Prevention (CDC) has issued a warning that measles could once again become endemic in the country. Measles cases in the first quarter of 2024 have surged to more than 17 times the number of cases reported between 2000 and 2023.

Back in 2000, the US achieved the highly sought-after status of measles elimination after an intensive vaccination campaign. This meant that the highly contagious measles virus was no longer continuously transmitted in the country for 12 or more months, thanks to an effective disease monitoring system. The number of children falling ill with measles was significantly reduced from millions to just a few travel-linked cases.

However, the current situation poses a threat to the US' elimination status. Measles cases in the first quarter of 2024 have skyrocketed, raising concerns among health officials. Compounding the issue, measles vaccination rates among kindergarteners have declined over the years, falling below the critical 95 percent target required to prevent sustained transmission.

Moreover, disruptions caused by the COVID-19 pandemic to routine childhood vaccination programs worldwide have contributed to a surge in measles cases globally. This increases the risk of imported cases spreading within the US.

To address this alarming trend, the CDC has published an analysis in its Morbidity and Mortality Weekly Report, examining the current measles cases and surveillance systems. The analysis reveals that the country's surveillance systems are effective in detecting transmission chains and isolated cases.

However, the CDC warns that relying solely on surveillance systems may not be enough. In 2019, the US came close to losing its elimination status during prolonged outbreaks in New York and New York City. With the worsening conditions, it is crucial to prepare for a potential resurgence.

The analysis highlights that the most likely scenario for a resurgence is when an unvaccinated US resident acquires the infection abroad and brings it back to an under-vaccinated community. Unvaccinated children in that community then contract the virus, leading to sustained transmission.

Between January 2020 and the end of March 2024, there were 338 reported measles cases, with a median age of 3 years old. Among these cases, 326 (96 percent) were linked to importation, and 12 cases (4 percent) had an unknown source. Of the 93 cases directly imported into the country, 59 (63 percent) were in US residents who were eligible for vaccination but remained unvaccinated or had an unknown vaccination status.

Out of the total 338 cases, 309 (91 percent) were either unvaccinated (68 percent) or had an unknown vaccination status (23 percent). The CDC stresses the need to address these gaps in vaccination coverage to prevent large-scale outbreaks and the potential return of measles as an endemic disease.

The analysis also reveals that in 2024, European and East Asian regions accounted for an increased percentage of measles importations into the US, further raising concerns about the global rise in measles incidence.

In conclusion, the CDC emphasizes the importance of improving measles vaccination rates, encouraging vaccination before international travel, identifying under-vaccinated communities, and promptly investigating suspected cases. These measures are essential to prevent measles from regaining its foothold in the US and maintain the country's hard-won elimination status.

Overall, while the US currently has sufficient vaccination coverage to prevent widespread outbreaks, it must remain vigilant and actively work to protect its population from the resurgence of measles.