Whooping cough on record-setting pace, fueled by resistant strains

Asahi Shimbun

22-06-2025

Cases of whooping cough are nearing record levels in Japan with the emergence of drug-resistant bacteria that are difficult to treat with conventional therapies.
So far this year, 16,475 patients were confirmed to have whooping cough as of May 11, approaching the record annual total of 16,850 for all of 2019, according to figures released by the Japan Institute for Health Security on May 20.
The current counting system for cases of whooping cough started in 2018. The illness is also known as pertussis or the '100-day cough,' since patients can suffer severe coughing fits for two to three months.
In March, a 1-month-old girl died from the illness at the Tokyo Metropolitan Children's Medical Center in Fuchu, western Tokyo.
She had initially been admitted to another hospital where she received an antimicrobial agent to treat her breathing difficulties. The infant was transferred to the medical center following respiratory failure.
The medical center believed the girl was infected with a pertussis-resistant bacterium and placed her on an artificial ventilator. She was given another antimicrobial drug known to work against resistant strains.
Nevertheless, her pneumonia progressed, leading to respiratory failure, pulmonary hypertension and renal insufficiency. She underwent extracorporeal membrane oxygenation (ECMO) and dialysis, among other treatments.
She died on the fifth day of her hospitalization at the medical center.
The girl had no underlying health problems, but she had yet to be inoculated against whooping cough from the Bordetella pertussis bacteria.
Yuho Horikoshi, head of the department of infectious disorders at the Tokyo Metropolitan Children's Medical Center, who was involved in the girl's treatment, noted the difficulty in treating babies with pertussis.
'Unvaccinated infants experience a much more rapid progression of the disease and are at higher risk of developing serious symptoms,' Horikoshi said. 'Lung damage brought on by Bordetella pertussis resulted in multiple organ dysfunction, making it virtually impossible for us to save her.'
Particular attention should be given to babies in the first few months of life as they are not immune to the disease, he said. Such infants are highly susceptible to lapsing into a severe condition while contracting encephalopathy and pneumonia.
They may die following convulsions, respiratory arrest or breathing cessation in apnea attacks, he said.
Macrolide antimicrobials are usually used in pertussis treatment. However, reports of bacterial strains resistant to this type of medicine have recently increased.
Five patients suffering from whooping cough, including the deceased girl, were found with 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 across Tokyo,' Horikoshi said. 'Specific steps should be taken, such as administering drugs known to be effective against resistant strains at an early stage for babies, who are especially prone to severe symptoms.'
Outside the capital, whooping cough cases caused by resistant bacteria have been confirmed since last year in Okinawa, Osaka and Tottori prefectures.
Vaccines can be effective against whooping cough, even antimicrobial-resistant strains, according to health experts.
Four doses are recommended for children between the ages of 2 months and 18 months under Japan's regular vaccination program.
Vaccinated individuals can still be infected after the effectiveness of the medicine wanes.
For this reason, the Japan Pediatric Society recommends that children receive an additional dose of the triple-combination vaccine containing the anti-pertussis component before entering elementary school or when they are 11 to 12 years old.
The voluntary vaccination costs 5,000 yen to 6,000 yen ($34 to $41). It is not covered by the public health program.
'Parents should get their babies vaccinated under the periodic preventive inoculation framework as soon as they turn 2 months old,' Horikoshi said.
'Whooping cough is discovered primarily among children from elementary school age to teenagers,' he continued. 'I ask that families with small children consider having siblings inoculated to protect their younger brothers and sisters if there are babies at home or when new babies are expected.'