Medical Advisory: Increase in Reported Pertussis Cases

Background

Hamilton Public Health Services (PHS) is notifying health care providers of an increase in the number of pertussis cases in Hamilton. There have been 17 cases reported between January 1, 2024, and September 30, 2024. In Hamilton, there were 19 confirmed pertussis cases in 2019 and 3 confirmed pertussis cases between 2020 to 2023 during the COVID-19 pandemic.

Key Messages for Health Care Providers

• Ensure your patients are up to date on their Tetanus, Diphtheria, and Pertussis vaccine (Tdap and DTaP), along with all other publicly funded vaccines. Refer to the current Publicly Funded Immunization Schedules for Ontario for more information.
• In Ontario, pertussis containing vaccines should be administered:
  • as part of the routine childhood vaccination series between 2 months old and 4 years old
  • as an adolescent booster at 14 years old
  • once in adulthood 10 years after their last dose of pertussis containing vaccine
• Persons who are pregnant are recommended to receive a pertussis containing vaccination with every pregnancy ideally between 27 to 32 weeks gestation.
• Consider pertussis as a differential diagnosis in patients presenting with clinically compatible signs and symptoms, particularly in patients who are not fully immunized.
• Fully immunized children and adults may also be susceptible to Pertussis due to waning immunity. However, they generally have less severe symptoms and fewer complications.

Signs and Symptoms:

Include a catarrhal stage characterized by mild upper respiratory tract symptoms with a mild cough lasting 1-2 weeks. During the paroxysmal stage, the cough increases in frequency and severity. The cough may be characterized as violent with or without an inspiratory whoop, commonly followed by vomiting. Fever may be absent or minimal. Young infants often have an atypical presentation and are at high-risk for serious complications. Symptoms can last for two to eight weeks. Pertussis is highly communicable in the early catarrhal stage and beginning of the paroxysmal stage (first 2 weeks). Communicability gradually decreases and becomes negligible in about 3 weeks.

Infection Prevention and Control:

Suspect cases of pertussis should be placed under droplet precautions in addition to routine practices. This includes the patient wearing a medical mask if able. Refer to the Public Health Ontario (PHO) best practice document Infection Prevention and Control for Clinical Office Practice for more information - https://www.publichealthontario.ca/en/health-topics/infection-prevention-control/clinical-office-practice

Testing Recommendations:

A nasopharyngeal (NP) swab obtained for PCR, ideally within the first 3 weeks of symptom onset, is recommended. This can be performed in a physician's office using a Bordetella pertussis kit, obtained from the Public Health Ontario Laboratory (PHOL) (kit order# 390052).

Complete all fields of the general test requisition form including symptoms, symptom onset date, exposure history, vaccination history, and test requested. Further information regarding Bordetella pertussis “Specimen Collection and Handling” can be found at the PHOL Test Information Index - https://www.publichealthontario.ca/en/laboratory-services/test-information-index/bordetella-respiratory

Exclusion:

Suspect cases of pertussis should stay home from childcare, school, or work, and should avoid contact with infants, young children and pregnant people. Cases of pertussis are no longer considered infectious after 5 days of effective antibiotic therapy or after 21 days post cough onset. Public Health will follow-up with suspect and confirmed cases of pertussis.

Vaccine Ordering:

Please call Public Health Services, Vaccine Program at 905-546-2424 ext. 7556 for questions about the Pertussis vaccine. To order Pertussis vaccine, physicians should use their Vaccine Order Form and fax it along with 4 weeks of logged (twice daily) current, minimum, and maximum temperatures to Vaccine Program Inventory at 905-546-3472 (fax).

Reporting Requirements:

Pertussis is reportable to the Medical Officer of Health under the Health Protection and Promotion Act,

R.S.O. 1990, c. H.7. To report suspect or confirmed cases of Pertussis, please contact the Infectious Disease Program at 365-323-8170, Monday through Friday, 8:30 a.m. to 4:30 p.m. After-hours, weekends, and holidays please call 905-546-2489 and ask to speak with the on-call Public Health Nurse.