Outbreak investigation of whooping cough from Bordetella pertussis and Bordetella parapertussis in Chong Maew sub-district, Lam Thamenchai district, Nakhon Ratchasima Province, Thailand, October–December 2018

Abstract

Introduction: On 2018 December 28, Office of Disease Prevention and Control Region 9th Nakhon Ratchasima (DPC9) was notified of 2 confirmed pertussis cases, 2 months old (index and dead) and 8 years old. In Lamthamenchai district, there was no report of pertussis patients during the years 2010-2018. A joint investigation team (JIT) conducted to confirm the outbreak, identify risk factors and implement the control measures on 2 January 2019.
Methods: We reviewed situation of whooping cough situation and medical records of patients. Active case finding was conducted in the school and community between 2 October 2018 to 2 January 2019. A suspected case had one of these symptoms: a history of at least 2 weeks of coughing, persistent cough, wheezing or vomiting after coughing. If there was an epidemiological link with a confirmed case, he/she was a probable case. The case was confirmed by Bordetella pertussis or Bordetella parapertussis from respiratory secretions by PCR method. We surveyed environment and estimated coverage of diphtheria, pertussis, and tetanus (DTP) vaccine based on mother and child health handbook.
Results: We found totally 8 patients, 3 confirmed cases (2 infected with B. pertussis and 1 infected with B. parapertussis) and 5 probable cases. The mean age was 9.5 years (range: 2 months to 28 years). The first patient became ill at early October 2018 and the last patient became ill on 28 December 2018. All patients joined activities with the first patient. DTP vaccine coverage of Lamthamenchai district among age group 0-6 years was 95.65%. Two confirmed cases had completed DTP vaccine but were not listed in the immunization register, as the list was not up to date. One confirmed case was not vaccinated because her age has not yet reached the immunization criteria. Seventy-eight children received catch-up DTP vaccine.
Conclusion: There was an outbreak of whooping cough with B. pertussis and B. parapertussis. The dead patient was younger than the age of vaccination. Therefore, policy for additional Tdap vaccine to pregnant women, to increase the immunity among young children, should be considered. Moreover, children registration and vaccination record should be regularly updated.