Syphilis Cases Remain High in Japan as Key Penicillin Treatment Faces Supply Shortage

Japan continues to report high levels of syphilis infections as the country faces a shortage of a key penicillin treatment, raising concerns over access to the first-line therapy, particularly for pregnant women at risk of transmitting the infection to their babies.

Syphilis cases in Japan have increased substantially over the past decade. The country recorded just over 1,000 cases in 2013, rising to nearly 8,000 cases in 2021 and more than 13,000 cases in 2025.

The increase has placed additional pressure on public health efforts to control the sexually transmitted infection at a time when supplies of an important penicillin treatment are constrained.

Japan Faces Shortage of Key Syphilis Treatment

Penicillin remains a first-line treatment for syphilis, with benzathine penicillin G playing a particularly important role in treatment.

Japanese medical societies announced in September that shipments of the long-acting benzathine penicillin product Stelues would stop after existing manufacturer inventories are exhausted. Supply restrictions are also affecting some amoxicillin products.

The supply problem follows a voluntary recall of Pfizer’s syphilis treatment in July 2025 because of foreign-matter contamination, followed by a manufacturing equipment failure in November 2025. The manufacturer expects shipments to resume around the second half of 2027, after preparations at the manufacturing facility and regulatory procedures are completed.

Pregnant Women Given Priority Amid Limited Supply

The shortage is particularly significant for pregnant women with syphilis.

Penicillin is the recommended treatment during pregnancy and is critical for preventing mother-to-child transmission of syphilis. Japanese medical experts have therefore called on healthcare providers to prioritize available supplies for pregnant patients while avoiding unnecessary prescribing and stockpiling during the shortage.

When syphilis is transmitted from a pregnant woman to her fetus through the placenta, it can lead to congenital syphilis, with serious consequences including stillbirth, premature birth and abnormalities affecting the nervous system and bones.

Syphilis Cases Have Risen Sharply Over the Past Decade

Japan has experienced a substantial resurgence of syphilis over the past several years.

Reported infections increased from 1,228 cases in 2013 to 7,983 in 2021, before exceeding 10,000 annually from 2022 onward. More than 13,000 cases were reported in 2025.

Local reports have linked the increase to changes in sexual behavior and the growing use of social media and dating applications, although the pattern of transmission is complex and should not be attributed to a single factor.

The continued high number of infections, combined with constraints on the supply of a key treatment, has prompted Japanese medical organizations to call for careful management of available penicillin supplies.

Syphilis Can Cause Serious Complications Without Treatment

Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum.

Without appropriate treatment, the infection can progress and potentially damage multiple organ systems, including the nervous and cardiovascular systems.

Transmission occurs primarily through sexual contact, while an infected pregnant woman can also transmit the bacterium to her fetus.

The current situation in Japan highlights the dual public health challenge of controlling persistently high syphilis infections while ensuring that limited supplies of essential treatment remain available to patients with the greatest medical need.

 

 

Source : Xinhua Thai News