Guidelines for the Public Health Management of Pertussis in England

Overview

This summary on the management of whooping cough covers testing and includes a management algorithm.

Algorithm for the Management of Cases and Close Contacts of Pertussis

Case Definition

• Suspected case of pertussis:
  • any person in whom a clinician suspects pertussis infection or
  • any person with an acute cough lasting for 14 days or more, without an apparent cause plus one or more of the following:
    • paroxysms of coughing
    • post-tussive vomiting
    • inspiratory whoop
• AND
  • absence of laboratory confirmation
  • no epidemiological link to a laboratory confirmed case
• Confirmed case of pertussis:
  • any person with signs and symptoms consistent with pertussis with:
    • B. pertussis isolated from a respiratory sample (typically an nasopharyngeal aspirates or nasopharyngeal swabs/pernasal swabs (or throat swab) or
    • anti-pertussis toxin IgG titre >70 IU/ml from a serum or >70 aU from an OF specimen (in the absence of vaccination within the past year)^[A] or
    • B. pertussis polymerase chain reaction (PCR)-positive in a respiratory clinical specimen

Epidemiologically Linked Case of Pertussis

• A suspected case with signs and symptoms consistent with pertussis, but no laboratory confirmation, who was in contact with a laboratory confirmed case of pertussis in the 21 days before the onset of symptoms

Recommended Details to be Recorded When a Case is Reported

• Caller details:
  • name, address, designation and contact number
• Demographic details:
  • name, date of birth, sex, ethnicity, NHS number
  • address including postcode
  • contact details including phone number
  • occupation (if applicable)
  • place of work/education (if applicable)
  • GP name and contact details (including address and phone number)
• Clinical/epidemiological details:
  • clinical information—onset dates, cough (including duration), presence of inspiratory whoop/apnoea/post-tussive vomiting, complications, treatment
  • need for admission to hospital (including dates where relevant)
  • pertussis immunisation history^[B] (including dates)
  • pregnancy status
  • contact with confirmed or suspected case
  • any close contacts within a priority group including:
    • healthcare workers in high-risk settings
    • unimmunised infants born after 32 weeks but less than 2 months of age whose mother did not receive pertussis vaccine after 16 weeks and at least 2 weeks prior to delivery
    • unimmunised infants born ≤32 weeks and less than 2 months of age regardless of maternal vaccine status
    • unimmunised or partially immunised aged 2 months and over regardless of maternal vaccine status
    • pregnant women >32 weeks and have not received pertussis vaccine at least a week prior to exposure
  • context: household, school, healthcare setting (including name)

Risk Assessment for the Index Case

• The positive predictive value (PPV) of a clinical diagnosis of pertussis is not very high, particularly among adolescents and adults who may present with atypical features. However, the PPV will increase during periods of heightened pertussis activity and will vary with age
• Risk assessment should be based on a combination of clinical and epidemiological factors such as clinical presentation, vaccination history and epidemiological links. Management of the index case and any vulnerable contacts should proceed based on this risk assessment without waiting for the results of laboratory testing and prompt public health actions to prevent onward transmission should be considered

Laboratory Confirmation and Public Health Action

• Appropriate public health action should not wait for laboratory results as negative results cannot be used to exclude pertussis infection. In the event of an outbreak, the local Health Protection Team (HPT) and the testing laboratory should be informed in order that testing can be appropriately prioritised
• Please contact Respiratory and Vaccine Preventable Bacteria Reference Unit (RVPBRU) on 0208 327 7327 and discuss with senior staff prior to sending serological specimens for priority testing. Please note, these services are not available outside of regular working hours at PHE Colindale, see user manual for details

Case Management

Exclusion

• See algorithm and full guideline for further details

Antibiotic Therapy

• The decision to offer antibiotics and the choice of treatment is a clinical decision. Ideally antibiotics should be administered as soon as possible after onset of illness in order to eradicate the organism and limit ongoing transmission. The effect of treatment on reducing symptoms, however, is limited or lacking especially when given late during the disease. For suspected, epidemiologically linked or confirmed cases, recommended antibiotic regimens are summarised in Table 1. Antibiotics are not recommended or thought to be beneficial after three weeks of symptoms

Immunisation

• It is important that unvaccinated and partially immunised cases up to 10 years of age complete their course of primary immunisation and booster vaccine once they have recovered from their acute illness, following the PHE guidance document Vaccination of individuals with uncertain or incomplete immunisation status
• Pregnant women who have been diagnosed with pertussis (at any stage of pregnancy) and have not been vaccinated after 16 weeks of pregnancy, should be offered a dose of pertussis containing vaccine in line with national recommendations. Pregnant women diagnosed with pertussis before 16 weeks gestation should wait until they reach 16 weeks of pregnancy (and ideally following the detailed ultrasound scan) to have the vaccine

Table 1: Recommended Antibiotic Treatment and Post Exposure Prophylaxis by Age Group^[A]

Contact Management

• Management of contacts should proceed for all clinically suspected, epidemiologically linked and laboratory confirmed cases

Definition of Close Contacts

• Family members or people living in the same household are considered close ‘household contacts’. Contacts in institutional settings with an overnight stay in the same room, e.g. boarding school dormitories, during the infectious period should also be considered close contacts. Other types of contact, eg contact at work or school, would generally not be considered close contact although each situation would need to be assessed on an individual basis where vulnerable contacts are involved. For the definition of a significant exposure in a healthcare setting, please refer to PHE Guidelines for the Public Health Management of Pertussis Incidents in Healthcare Settings
• Definition of contacts considered as priority groups for public health action These include individuals who are themselves at increased risk of complications following pertussis (Group 1) as well as those at risk of transmitting the infection to others at risk of severe disease (Group 2)
• Contacts of parapertussis do not require public health action

Group 1

• Individuals at increased risk of severe complications (‘vulnerable’):
  • unimmunised infants (born after 32 weeks) less than 2 months of age whose mothers did not receive pertussis vaccine after 16 weeks of pregnancy and at least 2 weeks prior to delivery
  • unimmunised infants (born < 32 weeks) less than 2 months of age regardless of maternal vaccine status
  • unimmunised and partially immunised infants (less than 3 doses of vaccine) aged 2 months and above regardless of maternal vaccine status

Group 2

• Individuals at increased risk of transmitting to ‘vulnerable’ individuals in ‘group 1’ who have not received a pertussis containing vaccine more than 1 week and less than 5 years ago:
  • a) pregnant women (>32 weeks gestation)
  • b) healthcare workers working with infants and pregnant women
  • c) people whose work involves regular, close or prolonged contact with infants too young to be fully vaccinated
  • d) people who share a household with an infant too young to be fully vaccinated

Exclusion of Contacts

• Exclusion for asymptomatic contacts is NOT required

Chemoprophylaxis of Contacts

• Given the limited benefit of chemoprophylaxis, antibiotic prophylaxis should only be offered to close contacts when both of the following conditions apply:
  • onset of disease in the index case is within the preceding 21 days AND
  • there is a close contact in one of the priority groups as defined above
• Where both these conditions are met, ALL close contacts of a confirmed case (regardless of age and previous immunisation history) should be offered chemoprophylaxis. The dose of antibiotics for use as chemoprophylaxis is the same as for the treatment of cases (see Table 1). Chemoprophylaxis is NOT required where there are no close contacts in the priority groups defined above, or for healthy contacts

Special Situations

• Please see full guideline for further details on special situations (e.g. healthcare settings, and nursery and school settings) 

Outbreaks 

• Where disease transmission is widespread, the benefit of wider chemoprophylaxis is likely to be of limited value. In the event of a hospital or community outbreak, an outbreak control team should be convened at the earliest opportunity and the local HPT informed. The priority in these circumstances is active case finding and therefore a less specific case definition should be used to ensure no cases are missed. Once laboratory confirmation of pertussis infection has been demonstrated in a cluster (e.g. school), it is not usually necessary to perform extensive additional testing. Further guidance on the management of cases during heightened periods of pertussis activity is on the PHE intranet
• An appropriate hospital incident control team is likely to include:
  • director of infection prevention and control
  • hospital microbiologist (if different)
  • infection control nurse
  • consultant/s from relevant clinical specialties
  • occupational health physician/nurse
  • Screening and Immunisation team representative
  • HPT representative
  • communications leads (from PHE and acute trust as necessary)
• For community outbreaks, include the relevant individuals listed above plus:
  • director of public health or their nominated representative
  • GPs or GP representative
  • NHS England or clinical commissioning group representative
  • school nursing service representative for a school outbreak
• Where appropriate, relevant lead public health microbiologist, field epidemiologist, RVPBRU and PHE Colindale Immunisation Department representatives should also be included
• Expert advice on outbreak investigation and management is available from Immunisation Services, NIS Colindale, PHE (020 8200 6868/4400) and on laboratory investigation from the Respiratory and Vaccine Preventable Bacteria Reference Unit (0208 327 7327)

Testing for Pertussis in Primary Care

• Suspect pertussis in patients with a cough illness lasting 14 days or more without an apparent cause plus one of the following:
  • (a) paroxysms of coughing
  • (b) inspiratory ‘whoop’
  • (c) post-tussive vomiting
• ALL CASES should be notified to your local HPT
• When notifying, it is helpful to let the HPT know if the case has had contact with pregnant individuals or children aged under 1 year, including through occupational exposure (e.g. healthcare or nursery settings)
• Recommended tests for pertussis testing vary according to the length of time since symptom onset:
  • less than 2 weeks from symptom onset: PCR and culture
  • between 2 and 3 weeks from symptom onset: PCR and culture and either OFK (oral fluid kit) (if aged 2 to < 17 years of age) or serology
  • more than 3 weeks from symptom onset: either OFK (if aged 2 to <17 years of age) or serology

Sending a Pertussis PCR Test—FREE SERVICE

• Please submit samples to your local laboratory as per normal protocol. Samples will then be referred for Pertussis PCR detection your local Public Health Laboratory (PHL). Pertussis PCR testing is not chargeable, when performed at a PHL. Please label clearly ‘for Bordetella pertussis PCR testing’

PCR Testing can be Performed on the Following Specimens:

• Collected using a virology swab or dry swab in a sterile container

Pernasal swabs

• Use a dry swab with a flexible wire shaft and a rayon/Dacron/nylon bud. A rigid shaft is not suitable. Push the swab along the floor of the nasal cavity, as far towards the posterior wall of the nasopharynx as possible

• Use a dry or Copan style nasopharyngeal swab. See this CDC video for further guidance

Nasopharyngeal aspirate

• Provide not less than 400 microlitres in a sterile container. See this CDC video for further guidance

Sending a Pertussis Culture

• A nasopharyngeal swab or pernasal swab may be taken for culture. The swab should be placed in a culture medium (ideally charcoal) and submitted to your local microbiology lab. Please clearly label as ‘for pertussis culture’

Requesting an Oral Fluid Kit—FREE SERVICE

• For cases aged 2 years to less than 17 years, notify the case to your local HPT and they will post an OFK directly to the case
• Note that oral fluid testing is not recommended if the case has been immunised against pertussis in the previous year as a positive result cannot be interpreted

Sending a Pertussis Serology Test

• For cases not aged 2 years to less than 17 years, a charged-for serology test using serum can be arranged via your local laboratory and then sent on to the RVPBRU. Form B3 can be used
• Note that serology is not recommended if the case has been immunised against pertussis in the previous year as the result cannot be interpreted

Managing Cases

• If three weeks or less from symptom onset, treat with appropriate antibiotics once PCR and culture tests have been taken. Exclude the case from school/work until they have completed two days of the antibiotic course. Work with the local HPT to identify and manage vulnerable close contacts. There is no need to prescribe a second course of antibiotics even if  symptoms are not resolving
• If more than three weeks from symptom onset, antibiotics are not required to manage pertussis even if  the case still has symptoms. No exclusion of the case is necessary
• Further information on the testing for and management of pertussis is available at: www.gov.uk/government/publications/pertussis-guidelines-for-public-health-management Or please call your local HPT for further advice

Footnotes

[A] This is currently under review and will be modified as more data is available

[B] Including pertussis vaccines administered to mother during pregnancy for cases born after 30 September 2012