Professor Takeda will give a special lecture on measles at the 57th Ammual Meeting of the Japanese Society for Pediatric Infectious Diseases.

https://square.umin.ac.jp/jspid57/

November 8-9, 2025

Grand Nikko Tokyo Bay Maihama

Chair: Tomoyo Matsubara (Professor, Department of Pediatrics, Saitama Medical Center, Dokkyo Medical University)

Special Lecture: Measles Control, Advances in Measles Virus Research, and Future Challenges

November 9, 2025, 10:40-11:40

Measles is an acute viral infection caused by the measles virus, characterized by high fever, widespread rash, and transient but profound immunosuppression. It is known for its extraordinary contagiousness and high mortality rate. Fortunately, live attenuated vaccines with excellent efficacy and safety were developed and has been in use for more than half a century. During this time, no clinically significant antigenic changes have been identified, and this classic vaccines continue to demonstrate uniformly high effectiveness against all circulating strains. Furthermore, since humans are the only natural host, thorough vaccination could theoretically lead to eradication. In fact, since the late 1990s, strengthened global control measures have resulted in a dramatic decline in measles cases. However, following the COVID-19 pandemic, control efforts have regressed, and resurgence has become a major concern.

Current measles control relies on the premise that “vaccine efficacy remains unchanged,” yet the scientific basis for this assumption is not fully understood. Because measles virus exhibits markedly different antigenic properties from other viruses in the genus Morbillivirus, the possibility of antigenic variation in measles virus itself cannot be ruled out.

The measles virus uses two cellular receptors, allowing infection of both immune and epithelial cells. After targeting immune tissues and establishing systemic infection, it releases massive amounts of progeny virus from the respiratory tract. However, whether this alone explains its extraordinary transmissibility remains uncertain. Moreover, the mechanisms underlying its rare but lethal central nervous system infections are still poorly understood, and no effective treatment is currently available.

From a clinical standpoint, differentiating circulating strains of measles virus is unnecessary; they can all be considered the same virus. Genotype classification was introduced mainly for epidemiological tracking. In recent years, however, only genotypes B3 and D8 have continued to circulate globally, while other genotypes have disappeared. Although it is possible that B3 and D8 possess features that favor transmission, no scientific evidence currently supports this assumption.

In this lecture, I would like to share what is known so far about measles and the measles virus, as well as the challenges that remain to be addressed.