Increasing Whooping Cough: The Outbreak in the First Half of 2025 Surpasses a Total of 31,966 Cases and Measures Foreign Families Should Take Now

1. Current Situation and Statistics of the Epidemic

1-1 Surpassing the Previous Record by a Large Margin

• Cumulative Number of Patients from Weeks 1 to 24 in 2025: 31,966 people (Preliminary Figures)nordot.app

• Already nearly double the highest record in 2019 (16,845 people), the highest since the start of the complete enumeration system (2018~).

• Weekly report numbers have exceeded 2,000 people every week since the 15th week. As of the 22nd week, the cumulative total is 22,351 people, more than five times the annual total of last yearid-info.jihs.go.jp.
  
  
  

1-2 Age Distribution and Regional Differences

• 58.7% of patients are aged 10-19. Ages 5-9 account for 21.0%, and ages 0-4 show a slight decreasing trendid-info.jihs.go.jp.

• Top reporting areas are Niigata, Tokyo, and Osaka, with the highest population ratio in Miyazaki (81.1 per 100,000 people)id-info.jihs.go.jp.
  
  
  

1-3 Comparison with International Trends

In Europe and the United States, a resurgence has been reported since the latter half of 2024, with the U.S. recording 35,435 cases in 2024, more than five times the previous yearid-info.jihs.go.jp. The common factors are considered to be the "immunity gap" during the pandemic and the decline in vaccination rates.

2. Basic Knowledge of Whooping Cough

1. Pathogen: Bordetella pertussis (rarely B. parapertussis).

2. Incubation Period: 7-10 days.

3. Typical Course: Catarrhal stage → Paroxysmal stage (continuous cough with whooping sound) → Recovery stage.

4. Complications: Pneumonia, seizures, and encephalopathy in infants; rib fractures and urinary incontinence in adults.

5. Treatment: Macrolides are the first choice. However, there is an increasing report of resistant strains (MRBP)id-info.jihs.go.jp.
   
   

3. Analysis of Factors Contributing to the Epidemic Spread

4. Points Foreign Residents Should Note

4-1 Discrepancies in Vaccine Schedules

Japan's five-in-one (DPT-IPV-Hib) four times + DT booster differs in number and interval from the DTaP three times + booster in the U.S. and EU, so completion in your home country ≠ full immunity in Japan. It is recommended to submit your vaccination history to the local government upon moving in and to cover any deficiencies with public or private funds.

4-2 Medical Institution Consultation Flow

• Prolonged cough (over two weeks) should raise suspicion of whooping cough, and you should first consult internal medicine or pediatrics.

• Check the list of clinics offering English and Chinese services on the websites of the international division or tourism bureau of each local government.

• Tests are mainly PCR/LAMP, covered by insurance (30% copayment). Even without insurance, you can consult for an estimate in advance.
  
  
  

4-3 Cocooning Vaccination

A strategy where family members, babysitters, and childcare workers surrounding infants receive Tdap (adult triple vaccine) to block the introduction into the household. In Japan, the recommended target was expanded to "cohabiting relatives and pregnant women" from 2023.

5. Symptom Checklist and Self-Care

6. Points on Treatment and Home Care

• Antibiotics: Early administration shortens symptoms and infectious period. Change based on culture results if resistant strains are suspected.

• Cough Attack Measures: Humidify the room (40-60%), provide small amounts of fluids frequently.

• Isolation Period: 5 days after starting antibiotics or 3 weeks after cough onset. Masks and ventilation are essential within the family.

• Return to Nursery/School: A medical certificate of recovery is generally required.
  
  

7. Latest Measures by Government and Companies

1. Ministry of Health, Labour and Welfare: Revised infection control guidelines for school facilities (dated June 14).

2. Tokyo: Distribution of multilingual leaflets for foreign parents (English, Chinese, Korean, Vietnamese).

3. U.S. Forces Japan and International Schools: Mandatory Tdap booster shots.

4. Companies: Promotion of telecommuting and flexible use of childcare leave.
   
   

8. Frequently Asked Questions (FAQ)

Q1. Do pregnant women need booster shots?
A. Tdap vaccination at 27-36 weeks of pregnancy transfers maternal antibodies to the fetus, enhancing early protection after birth.

Q2. Are masks effective?
A. The droplet nuclei size is larger than that of influenza, providing a certain protective effect with surgical masks.

Q3. Is PCR painful for infants?
A. Nasopharyngeal swabs are used, but it takes about 5 seconds. Prioritize breathing even if the infant cries, with no aftereffects.

9. Future Outlook

According to the IDWR bulletin, the 23rd week also exceeded 2,800 cases, remaining high. There is concern about inter-regional transmission during summer homecoming and travel, with experts pointing out that "the increasing trend may continue at least until the end of August." The timing of convergence will be influenced by the rate of additional vaccinations and the trend of resistant strains. Please check the weekly reports of the National Institute for Health Crisis Management for the latest information.

Reference Article List

1. Kyodo News "Whooping Cough Patients Exceed 30,000 - Nearly Eight Times Last Year, Infant Caution" June 24, 2025nordot.app

2. National Institute for Health Crisis Management IDWR 2025 Issue 22 "Notable Infectious Diseases: Whooping C