Pertussis Control and Response: A State Health Department Perspective Claudia Miller, M.S. claudia.miller@health.state.mn.us Minnesota Department of Health

Pertussis Pathogenesis Respiratory infection caused by Bordetella pertussis Toxin-mediated

Pertussis Clinical Manifestations Insidious onset; Catarrhal stage lasts 1-2 weeks Paroxysmal coughing with whooping and post-tussive vomiting lasts 1-6 weeks Convalescence over weeks or months, and symptoms may recur with subsequent URIs

Pertussis Epidemiologic Factors Incubation period: Generally 7-10 days (range from 5-21 days) Infectious period: During the catarrhal period until 2-3 weeks after cough onset Transmission occurs via aerosolized droplets

Pertussis Prevention Strategies: Immunization Vaccination is the best prevention strategy Standard recommendations: 3 doses at 2, 4, and 6 months of age Boosters at 15-18 months and 4-6 years of age Tdap for adolescents (and adults) Pertussis vaccine 70-90% efficacious after 3 doses Protection wanes after 5-10 years

Pertussis Prevention Strategies: Immunization, cont. Targeted pertussis vaccination proved to be a less-than-optimal strategy Vaccinating adolescents and adults is expected to decrease pertussis incidence, and should be promoted as part of public health investigations

Pertussis Prevention Strategies, cont. As an adjunct to immunization, additional pertussis prevention strategies include: Treatment of cases with antimicrobials Prophylaxis of case contacts with antimicrobials Minimizing exposures

The Role of Surveillance in Pertussis Prevention Surveillance data are used to: Measure disease burden and monitor trends Identify risk factors for infection and disease Identify pockets of need and prioritize resource allocation Inform prevention and control program planning and evaluation Enable public health officials to identify cases and recognize outbreaks for the purpose of implementing case-based disease prevention and control measures

Pertussis Surveillance in Minnesota Case-specific Universal (not sentinel) Passive supplemented by active laboratory audits which demonstrate that passive surveillance is effective

Surveillance Team Cases, suspect cases, case contacts Health care providers Laboratories Other professionals in work or institutional settings The “general public” Local public health Epidemiologists

Laboratory testing is performed Surveillance Pyramid Case is reported Laboratory testing is performed Specimen is obtained Person seeks care Person becomes ill

Pertussis Surveillance Challenges and Artifacts Pertussis is considered to be under-diagnosed Relatively mild symptoms in older children and adults May not seek medical care Laboratory testing is challenging May be treated empirically Higher index of suspicion increases diagnosis and reporting

REPORTED PERTUSSIS CASES BY COUNTY, MINNESOTA, 2005 (N =1571) Kittson Roseau Lake of the Woods 2 Marshall 2 Koochiching Beltrami 5 St. Louis 21 Polk Pennington 3 65 Cook 2 1 Red Lake Clear Water Lake Itasca 4 13 Norman Mahnomen 7 Hubbard Cass 1 Clay Becker 24 7 Aitkin REPORTED PERTUSSIS CASES BY COUNTY, MINNESOTA, 2005 (N =1571) Wadena Crow Wing Carlton Wilkin Ottertail 16 9 5 2 Pine Todd Mille Lacs 2 Kanabec Grant Douglas 8 2 1 1 7 Morrison 8 Benton Traverse Stevens Pope 6 Stearns 9 Isanti 29 Big Stone 104 6 Sherburne Greater Minnesota: 866 (55%) Metro 7-County Region : 705 (45%) 1 29 Chisago Swift 10 Anoka Kandiyohi 120 Wash- ing- ton 6 Meeker Wright Lac Qui Parle Chippewa 12 25 238 Ram- sey 4 108 19 Hennepin McLeod 70 Renville Carver 16 9 124 Yellow Medicine 2 12 Scott 36 Sibley 1 Dakota Lincoln Lyon Redwood Le Sueur 12 6 1 Nicollet Rice Goodhue 19 7 4 12 Wabasha Brown 12 Pipe-stone 2 Blue Earth Steele Murray Cottonwood Watonwan Waseca Dodge Olmsted 11 42 29 7 160 Winona 4 1 Rock Nobles Jackson Martin Faribault Freeborn Fillmore Houston 3 3 Mower 2 9 4 18 3 6

REPORTED PERTUSSIS CASES BY COUNTY, MINNESOTA, 2003 (N = 207) Kittson Roseau Lake of the Woods Marshall Koochiching Beltrami St. Louis Polk Pennington 6 7 Cook 1 Red Lake Clear Water Lake Itasca Norman Mahnomen Hubbard Cass Clay Becker Aitkin REPORTED PERTUSSIS CASES BY COUNTY, MINNESOTA, 2003 (N = 207) Wadena Crow Wing Carlton Wilkin Ottertail 4 1 Pine Todd Mille Lacs 2 Kanabec Grant Douglas Morrison 1 Benton Traverse Stevens Pope 4 Stearns Isanti 3 Big Stone 2 Sherburne 3 Chisago Metro 7-County Region : 137 (66%) Greater Minnesota: 70 (34%) Swift 1 Anoka Kandiyohi 7 Wash- ing- ton 2 Meeker Wright Lac Qui Parle Chippewa 1 1 68 Ram- sey 1 14 Hennepin McLeod 11 Renville Carver 2 26 Yellow Medicine 2 1 Scott 9 Sibley Dakota Lincoln Lyon Redwood Le Sueur 4 2 Nicollet Rice Goodhue 1 Wabasha Brown Pipe-stone Blue Earth Steele Murray Cottonwood Watonwan Waseca Dodge Olmsted 1 1 7 Winona 1 1 Rock Nobles Jackson Martin Faribault Freeborn 1 Mower Fillmore Houston 4 1 5

Pertussis Prevention: Identification and Reporting of Suspect Cases Pertussis should be suspected in: Individuals exhibiting a prolonged cough, especially lasting >2 weeks Individuals exhibiting paroxysmal cough of any duration and/or post-tussive vomiting, whooping, or apnea Individuals exhibiting a cough illness with known exposure to an infectious case of pertussis within 3 weeks prior to onset

Preventing Pertussis: Treatment of Cases Recommended within first 3 weeks of cough Antimicrobial treatment is less effective as cough progresses Antimicrobials reduce the contagious period Cases are rendered noninfectious after five days of appropriate antimicrobials

Preventing Pertussis: Prophylaxis of Case Contacts Recommended for “close contacts”of confirmed cases of pertussis Of benefit within the three weeks of exposure The same regimen is used for both treatment of cases and prophylaxis of case contacts Recommendations should be made in support of judicious use of antimicrobials

Preventing Pertussis Transmission, cont. Close contacts* include: Persons who have been exposed to an infectious case of pertussis for at least 10 hours/week, generally within arms’ length of the case Persons with direct face-to-face exposure to an infectious case while the case is coughing * Criteria determined by Minnesota state and local health department epidemiologists who are experienced with pertussis case investigations

Preventing Pertussis: Minimizing Exposures Potentially infectious persons should stay home to avoid exposing others, and be excluded from school, childcare, and other activities

Pertussis Investigation When a suspected or confirmed case of pertussis is reported, epidemiologists at the state or local health department contact the case (or parent/guardian) to: Answer questions and address concerns Determine potential exposure situations Request permission to discuss suspect case/case with others as necessary (e.g., school nurse) Note: Personally identifying information is not shared without consent.

Pertussis Investigation, cont. Public health interventions are initiated only for confirmed cases; however, Reporting of suspect cases enables public health to: Direct health care providers to current treatment and control guidelines Assist providers in responding to patients’ concerns Address and occasionally correct misinformation or avert inappropriate actions

Pertussis in School or Childcare Parents of close contacts receive: Notification of exposure General information about pertussis Instruction to contact their healthcare provider regarding: Prophylaxis (in accordance with standard guidelines) Vaccination, if indicated Medical evaluation, if symptoms develop

Pertussis in School or Childcare: Prophylaxis Recommendations Prophylaxis is routinely recommended for: All home daycare contacts Childcare contacts in the same classroom, and perhaps for others depending on Age of contacts Extent of exposure Elementary school: classroom Secondary school: activities

Pertussis Transmission in Secondary Schools: Outbreaks in secondary schools have been demonstrated to occur primarily among social circles and students participating in the same activities (e.g., sports, music)

Pertussis in School or Childcare, cont. Parents of students who are not close contacts may receive: Notification of pertussis in the school or community General information about pertussis Instruction to contact their health care provider regarding: Vaccination, if indicated Medical evaluation if symptoms develop

Pertussis in School or Childcare, cont. Decisions about broad notification are based on: Outbreak potential “Rumor mill” Local healthcare providers are apprised of any broad notification and public health recommendations Health alerts are issued for large outbreaks or situations affecting the broader community

Issues and Challenges Case-based investigations and public health interventions are very labor-intensive and costly Cases may not be identified in a timely manner Not recognized Testing not performed Not reported

Issues and Challenges, cont. Parents often oppose exclusion recommendations Healthcare providers may not support exclusion recommendations Communication with parents and healthcare providers can help avert problems with school exclusion

In Conclusion Early identification and reporting of cases; prompt public health intervention; and proactive communication with cases, contacts, and healthcare providers are essential to pertussis prevention and control. Uptake of Tdap vaccine will likely decrease pertussis incidence, thus reducing the need for public health investigations and interventions.

Acknowledgements Cynthia Kenyon, MPH Epidemiologist Minnesota Department of Health cynthia.kenyon@health.state.mn.us Local Epidemiology Network of Minnesota MDH District Epidemiologists