Whooping Cough Cases Surge in Japan Amid Drug-Resistant Bacteria

Whooping cough cases in Japan are approaching record levels, with the emergence of drug-resistant bacteria posing a significant challenge to treatment. As of May 11th of this year, 16,475 cases had been confirmed, nearing the record annual total of 16,850 for the entire year of 2019. The current system for tracking whooping cough cases began in 2018. This illness, also known as pertussis or the "100-day cough," can cause severe coughing fits lasting for several months.

In March, a one-month-old girl died from whooping cough at the Tokyo Metropolitan Children’s Medical Center. She had initially been treated at another hospital with an antimicrobial agent. However, she was transferred to the medical center due to respiratory failure. The medical center suspected a pertussis-resistant bacterium and placed her on a ventilator, administering another antimicrobial drug known to be effective against resistant strains. Despite these efforts, her condition worsened, leading to multiple organ failure.

The infant, who had no underlying health issues, had not yet been vaccinated against whooping cough. Yuho Horikoshi, head of the department of infectious disorders at the Tokyo Metropolitan Children’s Medical Center, highlighted the difficulty in treating babies with pertussis. Unvaccinated infants experience a rapid disease progression and are at higher risk of serious symptoms. Lung damage caused by the bacteria can lead to multiple organ dysfunction, making it difficult to save them.

Macrolide antimicrobials are typically used to treat pertussis, but reports of drug-resistant bacterial strains are increasing. Five patients, including the deceased girl, were found to have drug-resistant bacteria between November 2024 and March 2025 at the Tokyo Metropolitan Children’s Medical Center. Resistant bacteria are believed to be spreading significantly in Tokyo. Cases caused by resistant bacteria have also been confirmed in other prefectures.

Vaccines remain effective against whooping cough, even against antimicrobial-resistant strains. Japan's regular vaccination program recommends four doses for children between 2 and 18 months old. The Japan Pediatric Society recommends an additional dose of the triple-combination vaccine before elementary school or when children are 11 to 12 years old. Parents are advised to have their babies vaccinated as soon as they turn two months old. Families with young children are encouraged to consider vaccinating siblings to protect younger children.