Unprecedented increase in syphilis cases among heterosexual men and women in Japan, 2021-2022

Based on national surveillance data, we describe an unprecedented increase in syphilis case reports in Japan, with a surge in 2021-2022 reaching 10 141 cases in Week 42, 2022, a 1.7-fold increase over the same period in 2021. This already represented the highest annual case count in nearly half a century; by Week 52, 2022, the number reached 12 966, far surpassing the 7978 cases in 2021. Predominantly affecting heterosexual men and young women, the proportionate increase in primary and secondary syphilis cases suggests a true increase in incidence. The syphilis surge during the pandemic poses a serious public health concern and underscores the importance of adequate testing and preventive measures.

Automated summary

Based on national surveillance data, there has been an unprecedented increase in syphilis cases in Japan. In 2021-2022, the number of cases surged to 10,141 in Week 42, 2022, marking a 1.7-fold increase compared to the same period in 2021. This represents the highest annual case count in almost 50 years, reaching 12,966 cases by Week 52, 2022, far exceeding the 7,978 cases in 2021. The increase in primary and secondary syphilis cases, predominantly among heterosexual men and young women, suggests a true rise in incidence. The syphilis surge during the pandemic poses a serious public health concern and highlights the importance of adequate testing and preventive measures.