Series of National Guidelines (SoNGs)
Pertussis
National guidelines for public health units
The Series of National Guidelines have been developed in consultation with the Communicable Diseases Network Australia and endorsed by the Australian Health Protection Committee. Their purpose is to provide nationally consistent advice and guidance to public health units in responding to a notifiable disease event. These guidelines capture the knowledge of experienced professionals, build on past research efforts, and provide advice on best practice based upon the best available evidence at the time of completion.
Communicable disease factsheet
Print friendly version of Pertussis: National guidelines for public health units (includes the Investigation form) (PDF 326 KB)
Endorsed by CDNA: 29-30 July 2008
Endorsed by AHPC: OOS item, September 2008
Released by DoHA: 19 February 2009
| Revision history | |||
|---|---|---|---|
| Version | Date | Revised by | Changes |
1.0 |
19 February 2009 |
VPDS, OHP |
Updated URL links and addition of link to state and territory legislation |
Disclaimer
The guidelines are necessarily general and readers should not rely solely on the information contained within these guidelines. The information contained within these guidelines is not intended to be a substitute for advice from other relevant sources including, but not limited to, the advice from a health professional. These guidelines are intended for information purposes only. The membership of the Communicable Disease Network Australia (‘CDNA’) and the Commonwealth of Australia (‘the Commonwealth’), as represented by the Department of Health and Ageing, does not warrant or assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, or process disclosed at the time of viewing by interested parties.
The CDNA and the Commonwealth expressly disclaim all and any liability to any person, in respect of anything and of the consequences of anything done or omitted to be done by any person in reliance, whether in whole or in part, upon the whole or any part of the contents of this publication.
1. Summary
Public health priority
High for cases notified within 5 weeks of onset of symptoms who are:No action is required for cases notified > 5 weeks after date of onset of cough or > 5 weeks after the date of the laboratory result, unless they are reported to be part of a cluster.
Case management
It is the responsibility of the treating doctor to treat infectious cases. For cases under 5 years of age or cases of any age who are NAT or culture confirmed, contact the treating doctor and the case to identify contacts at high risk of disease, and advise infectious cases against mixing with vulnerable contacts, and to identify risk factors. Exclude infectious cases from work, school, preschool and childcare. For other cases, an advisory letter may be sent to the treating doctor, as required.Contact management
For cases under 5 years of age or cases of any age who are NAT or culture confirmed, or cases reported to have close contacts who may be at high risk for pertussis, counsel contacts at risk of disease and facilitate preventive therapy. Recommend that contacts’ immunisations be updated if need be. Exclude unimmunised children from preschool and childcare.2. The disease
Infectious agents
The bacillus Bordetella pertussis.Mode of transmission
Pertussis is transmitted by droplet infection and direct contact with discharges from respiratory mucous membranes of infected persons.Timeline
The incubation period ranges from 6 to 20 days, but on average is 7 to 10 days.Infectious period
Pertussis is highly communicable in the catarrhal and early coughing stage. Communicability gradually decreases thereafter and is negligible 3 weeks after onset of cough. For practical purposes, a case is considered non-infectious 3 weeks after onset of cough, or until they have completed 5 days of a course of effective antibiotics.Clinical presentation
The usual clinical presentation is an initial catarrhal stage with an irritating cough and sneezing, which gradually becomes paroxysmal. The paroxysms become more severe, and may end in vomiting, cyanosis and/or a characteristic high-pitched inspiratory “whoop”. The cough may last >3 months after resolution of the infection. Infants <6 months old, immunised children and adolescents and adults often do not show a typical clinical picture. Classical whooping is more likely in unimmunised children. In adult index cases, paroxysmal cough is often the main symptom but in adult contacts, a cough may be non-specific. Note that sub-clinical infections may occur.Top of page
3. Risk assessment
Routine prevention activities
Pertussis immunisation, as part of DTPa vaccine, is recommended for all Australian children at ages 2, 4, and 6 months, with a DTPa booster at 4 years of age and dTpa booster at 12–17 years of age. Since 2003, dTpa vaccine has been recommend for health care workers and people working or living with small children, including parents, grand parents, those planning pregnancy and child care workers who have not previously had a dose of the acellular vaccine.Threat and vulnerability
Pertussis was very common in infants before immunisation programs were introduced into Australia in the 1940s with deaths rates reported to be >4/100,000. Infants may not be protected until they have received the primary vaccine series. An individual’s immunity wanes after a few years, and so a booster dose is required at age 4 years. Pertussis has only been recently recognised widely as a common disease of older children and adults and lower-dose vaccines suitable for use in this age group have only been available since 2001. Despite improved rates of childhood vaccination, pertussis notifications in babies <6 months of age have changed little, and deaths are occasionally reported in this group (nine were reported nationally in the 1996-7 outbreak). Studies of cases notified in NSW in 2004 and 2006 found that cases aged <5 years (followed by 5 to 9 year olds) were the age group most likely to have to have close contacts eligible for preventive therapy.Top of page
Risk mitigation
The main aim of public health measures against pertussis is to protect those at risk for most severe disease and death, i.e., infants who have not received the primary vaccination series. For infants younger than 6 months, protection through immunisation of likely contacts, and reducing exposure to persons with cough are the only available strategies. Persons with coughing illnesses should be encouraged to seek medical attention and treatment if pertussis is diagnosed (to reduce infectiousness). Preventive antibiotic therapy is of limited benefit and best focussed on those most likely to be infectious and in contact with vulnerable infants.Because children <5 years of age are most likely to have high risk contacts who will benefit from preventive therapy, and cases of any age who are NAT or culture positive are most likely to be infectious to other people, these cases have priority for follow up.
4. Surveillance objectives
5. Data management
Within 3 working days of notification, enter confirmed, and probable cases onto the notifiable diseases database. Vaccination status, including “number of doses”, and “last dose verified by”, must be completed for all cases under 5 years of age. ACIR should be entered as the verification method where available. If not available, then GP record or Blue book (as quoted by the doctor or parent) should be entered.6. Communications
Within 1 working day of a death from pertussis:Top of page
7. Case definition
The current national surveillance pertussis case definition can be found at: www.health.gov.au/casedefinitions8. Laboratory testing
Testing guidelines
Routine testing of patients is at the discretion of the treating doctor. Where a probable case who has neonatal contacts is reported, the PHU should encourage testing to confirm the case.The best tests to confirm the diagnosis of pertussis varies according to age.
Nucleic acid testing (NAT)
Culture
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Serology
IgA on respiratory samples
Direct fluorescent antibody (DFA)
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9. Case investigation
Response times
Investigation
Begin the investigation within 1 day of notification of a probable or confirmed case who is:No action is required for cases notified > 5 weeks after date of onset of cough or > 5 weeks after the date of the laboratory result, unless they are reported to be part of a cluster.
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Response procedure
Case investigation
Cases aged under 5 years of age or cases of any age who are NAT or culture confirmed or cases reported to have close contacts who may be at high risk for pertussis
Only these cases need be investigated by PHU staff, unless assistance is requested. The response to a notification will normally be carried out in collaboration with the case’s doctor. PHUs should contact the treating doctor and the patient (or carer) if need be and:Cases aged 5 years and older who are not NAT or culture confirmed
For these cases, follow up may be limited to sending a letter and Fact Sheet to the treating doctor with recommended follow up actions. The offer for PHU staff to assist may be made where either high risk contacts or clusters are identified by the treating doctor. Follow up letters to the treating doctor are not required routinely if the PHU believes that the doctor is aware of the information in the letter.Case treatment
Antibiotics given early in the catarrhal stage may attenuate the disease but may have little effect on symptoms if given later. Importantly, antibiotics reduce the period of communicability and should be initiated as soon as possible and within three weeks of the onset of the cough.Treatment is the responsibility of the attending doctor. For recommended treatment see the latest edition of Therapeutic Guidelines: Antibiotic. In 2006 this was updated to:
In babies <1 month old, erythromycin is not recommended because of concerns it may cause pyloric stenosis, and clarithromycin is not recommended because safety data are not available.
Therapeutic Guidelines: Antibiotic notes that there is currently insufficient clinical evidence to recommend the use of roxithromycin for the management of pertussis.
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Education
The case or relevant care-giver should be counselled about the nature of the infection and the mode of transmission. Emphasis should be placed on minimising exposure to susceptible persons, especially infants. The Fact sheet is useful for this purpose.Isolation and restriction
Cases should be excluded from work, school, preschool, and childcare, and should be advised not to attend other settings, especially where there are young children, until they are no longer infectious (i.e., for 21 days from the onset of cough, or until they have completed 5 days of a course of effective treatment).Active case finding
None routinely required, except in special situations (see 12).10. Control of environment
None routinely required.11. Contact management
Identification of contacts
The aim of identifying contacts is to:Direct contact with respiratory secretions from the case is generally considered significant. However, it is necessary to take into account the degree of risk to the individual contact and the nature of exposure. For example, a high probability of infection could be assumed for an infant who remained in the same room as a case for an hour or a newborn directly exposed to a case coughing. Children <1 year old are at the greatest risk from pertussis and its complications, especially if they have received fewer than three doses of DTP vaccine. Because pertussis is spread by droplets rather than by airborne particles, contacts who have been within 1 metre of the case are at highest risk. High-risk activities include kissing, mouth-to-mouth resuscitation, dental examination or medical examination of the nose, mouth or throat.
Contact definition
Contacts are defined as people exposed to an infectious cases in the previous 3 weeks who are in the following categories:These contacts should be alerted to the possibility that they could develop disease. Note that the PHU can inform contacts via a third party (eg, doctor, parent or friend) where the PHU is confident that accurate information will be conveyed to the contact by the third party. Where the PHU becomes aware of settings with multiple cases, the PHU should inform others in the group at risk by organising for them to receive a letter and Fact Sheet (see section 12).
Prophylaxis
Passive immunisation
Normal human immunoglobulin (NHIG) is not effective against pertussis.Active immunisation
Since a primary course of 3 or more injections is required to protect against pertussis, infant vaccination cannot be effectively used to control an outbreak. However, incompletely vaccinated contacts and others who are routinely recommended to receive adult pertussis vaccination (such as healthcare workers and others in regular contact with young children) are likely to benefit in the future if they receive pertussis vaccination.Antibiotic prophylaxis
There is little evidence that preventive antibiotics reduce secondary transmission outside of household settings. The recommended antibiotics may have associated side effects (especially gastrointestinal) that reduce compliance. Therefore preventive antibiotics should be limited to those close contacts of cases who may either develop severe complications of pertussis or transmit pertussis in settings such as childcare facilities or healthcare facilities. If a case occurs in childcare settings, where there is a child under 12 months of age, the rationale for prophylaxis is to protect both the individual and stop transmission to vulnerable child(ren). If a case occurs in a care group that does not contain a child under 12 months the primary rationale is to protect the individual.Based on these principles, prophylaxis is recommended only for the following contacts of pertussis cases:
Antibiotic prophylaxis is not considered valuable in other settings such as primary schools, high schools, tertiary institutions and work places.
The antibiotics, doses and duration are the same as for cases (Section 9). Antibiotics should only be given if they can be commenced within 21 days of the last contact with an infectious case.
Prophylaxis is usually arranged through the contacts’ usual doctor, to ensure that the contacts are provided with medical support and follow up. However it should be noted that Azithromycin, especially the syrup form, may be difficult and/or expensive to obtain and that specific assistance may be required.
Prophylaxis may be recommended for each new episode of exposure satisfying the above criteria unless the contact was receiving prophylaxis at the time.
Education
PHU staff should manage the distribution of information to contacts (usually in the form of a letter and Fact Sheet) through the treating doctor, or if required, directly, or via the case or other intermediatory (e.g., director of the childcare centre, school principals, hospital infection control staff, etc).Isolation and restriction
Child contacts in the same room as the case who have not received 3 effective doses of vaccine should be excluded from preschool and childcare until the expiry of 14 days from their last exposure to the infectious case, unless they have already completed 5 days of a course of effective antibiotic treatment, in which case they may return.12. Special situations
Cases among children at school or in childcare
In addition to usual case investigation, it is important to emphasise to parents, school principals and directors of childcare facilities the need to verify each child’s immunisation status and the need for parents to remain alert for symptoms and to comply with the recommended immunisation schedule.It is also important to recommend that the facility remain alert for respiratory illness within 21 days of last contact with the infectious case and to recommend appropriate management of any further cases.
The PHU should prepare a letter for distribution through the school or childcare facility detailing the risk and actions to take (sample attached) to be sent with a Fact sheet to parents of children attending the same class as the case.
Antibiotic prophylaxis recommendations for other children and adults in the same classroom as the case are listed in Section 11.
Case in a health care worker in a maternity ward or newborn nursery
For probable or confirmed cases, consult immediately with facility management and staff from infection control or staff health to institute a management plan appropriate to the facility. This should include procedures for:The decision to administer post exposure prophylaxis is made after considering the infectiousness of the patient, the intensity of the exposure (within a distance of a metre and cumulative exposure for more than one hour is usually required for infection), the potential consequences of severe pertussis in the contact and the possibilities for secondary exposure of person at high risk from the contact (i.e. infants). In light of this, prophylaxis is usually recommended for:
Contacts among pregnant women
Maternal antibodies may not protect newborn babies against pertussis. For this reason, pregnant women with pertussis onset within a month of expected delivery should be given oral erythromycin (250 mg 4 times daily for 7 days). If the baby is born within 3 weeks of the mother’s onset of cough, then the baby and all household contacts should receive preventive therapy.Outbreaks
Where outbreaks of pertussis are identified, then additional control measures should be considered. Depending on the people affected and nature of the setting, control strategies may include:Use of antibiotic prophylaxis beyond the groups recommended in section 5 is difficult to justify.
If an outbreak occurs in a health care facility, an outbreak management team should be convened, including a senior facility manager, PHU staff, an infection control practitioner and appropriate clinical staff.
13. Additional sources of information
14. Appendices
15. Jurisdiction specific issues
Links to State and Territory Public Health Legislation and the Quarantine Acthttp://www.health.gov.au/internet/main/publishing.nsf/Content/cda-state-legislation-links.htm
NSW
Legislation
NSW Public Health Act 1991Pertussis is to be notified by:
Policies
Occupational Assessment, Screening & Vaccination Against Specified Infectious Diseases PD2007_006Cases aged 5 to 19 years are followed up by public health units to verify their case status and immunisation history and consequently the impact of the school-based immunisation program.
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Follow up of cases 5-19 years of age
In NSW, to assess the impact of high school based adolescent pertussis immunisation program cases aged 5-19 years are also followed up by PHUs; and to assess whether additional population-based control measures may be required to prevent infection in infants, the likely source of infection in children <2 years old is sought.Top of page
PHU Checklist for pertussis cases notified with 5 weeks of date of onset who are:
Patient ID number: ____________
Contact the patient’s doctor to:
Contact the patient’s care giver to:
Contact ACIR to:
Confirm case
Contact patient’s contacts to:
Other issues:
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Sample letter to doctors who diagnose pertussis in a case aged 5 years or older who is not NAT or culture confirmed
ConfidentialDear Doctor,
We recently received a notification from <notifier> that one of your patients <name> tested positive for pertussis on <date>. In patients who have symptoms consistent with pertussis, a positive test can help confirm the diagnosis. If your patient has pertussis, the following recommendations can help prevent further spread of pertussis to your patient’s close contacts.
Step 1. Case management
Specific antibiotics are recommended to treat pertussis. These are useful to reduce the patient’s infectiousness and may also reduce symptoms if given early. Antibiotics are not required if more than 3 weeks has elapsed since onset of coughing.
Cases should be treated with clarithromycin, azithromycin or erythromycin. If an alternative is needed, use: trimethoprim+sulfamethoxazole (see: Therapeutic Guidelines: Antibiotic for details).
Advice to the patient:
Advise the patient to stay away from susceptible people -- especially infants or young children -- until he/she is no longer infectious (i.e., the first 5 days of a course of treatment, or for 21 days after the onset of the cough.)Step 2. Identification of close contacts who may be at high risk
It’s important to identify other people who may be at high risk of pertussis in whom infection could be severe, as these will require preventative antibiotics. These people include any woman in the last month of her pregnancy regardless of her vaccination status, and all household members if the household includes a child aged <24 months who has not had 3 effective doses of pertussis vaccine.
Antibiotic prophylaxis may be recommended for other contacts too. Please call the public health unit to help follow up contacts, including those in institutions, if your patient:
Immunisation is the mainstay of pertussis control. Adults who have contact with young children should be offered immunisation against pertussis.
A fact sheet about pertussis is attached for your patient. Please ask your patient to share this information with any other household members or close friends that may have been exposed.
Pertussis is a notifiable disease and doctors should notify patients diagnosed with pertussis by telephoning the local public health unit as soon as the diagnosis is suspected.
If you believe that your patient has contacts at high risk of pertussis in whom infection could be severe, is part of an outbreak or you would like further advice on the public health management of pertussis, please call the public health unit on <telephone>. Thank you for your help in this important matter.
Yours sincerely,
<Name> <Director, xxx PHU> <date>
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Sample letter to doctors who diagnose pertussis in a case within 5 weeks of date of onset who is <5 years of age or of any age and nucleic acid test (NAT) or culture confirmed
ConfidentialDear Doctor,
We recently received a notification from <notifier> that one of your patients <name> tested positive for pertussis on <date>. In patients who have symptoms consistent with pertussis, a positive test can help confirm the diagnosis. If your patient has consistent symptoms, the following recommendations can help prevent further spread of pertussis to your patient’s close contacts.
Step 1. Case management
Specific antibiotics are recommended to treat pertussis. These are useful to reduce the patient’s infectiousness and may also reduce symptoms if given early. Antibiotics are not required if more than 3 weeks has elapsed since onset of coughing.
Cases should be treated with clarithromycin, azithromycin or erythromycin. If an alternative is needed, use: trimethoprim+sulfamethoxazole (see: Therapeutic Guidelines: Antibiotic for details). [In babies <1 month old, erythromycin is not recommended because of concerns it may cause pyloric stenosis, and clarithromycin is not recommended because safety data are not available.]
Advice to patient and parent
Advise the patient to stay away from school, preschool, childcare or other settings where there may be susceptible young children until he/she is no longer infectious (i.e. the first 5 days of a course of recommended treatment, or for 21 days after the onset of the cough.)
Step 2. Identification of close contacts who may be at high risk
It’s important to identify other people who may be at risk of pertussis in whom infection could be severe, as these will require preventative antibiotics. These people include any woman in the last month of her pregnancy regardless of her vaccination status, and all household members if the household includes a child aged <24 months who has not had 3 effective doses of pertussis vaccine.Antibiotic prophylaxis may be recommended for other contacts too. Please call the public health unit to help follow up contacts, including those in institutions, if your patient:
A public health unit staff member will contact you directly to assist in the public health follow up of this patient. If you require information sooner, please call the unit on <telephone<.
Immunisation is the mainstay of pertussis control. Adults who have contact with young children should be offered immunisation against pertussis.
A fact sheet about pertussis is attached for your patient. Please ask your patient or the parent to share this information with any other household members and close friends that may have been exposed.
Pertussis is a notifiable disease and doctors should notify the diagnosis by telephoning the local public health unit as soon as the diagnosis is suspected.
Thank you for your assistance in this important matter.
Yours sincerely,
<Name> <Director, xxx PHU> <date>
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Sample letter to parents of a child in a childcare facility or preschool with pertussis
Dear Parent,
Pertussis (whooping cough)
A child from the [name of the particular class at the particular facility] has been diagnosed with pertussis (whooping cough). I am writing to provide advice and to ask that you watch out for the symptoms of pertussis in your child, especially over the next 3 weeks.What is pertussis?
Pertussis is an infection of the throat that can cause bouts of coughing, and sometimes breathing difficulties and vomiting. It can be a very serious infection in small children. The illness can last for many weeks. It usually starts with a snuffle or a cold.What should people sick with pertussis do?
If your child develops symptoms, please take your child and this letter to your local doctor as soon as possible. Your doctor can advise whether pertussis is likely and arrange for early treatment if needed. Treating people who have pertussis with antibiotics can stop the infection spreading, but is more effective if started early.To help prevent this infection spreading, people who have been diagnosed with pertussis should not attend [the facility] until they have completed the first 5 days of a course of the recommended antibiotics. If antibiotics cannot be taken, then they must stay away for 3 weeks after onset of the cough.
How is it prevented?
Vaccination is the most important way of reducing pertussis in our community. It is important to double check that your child is fully up to date with his or her immunisations against pertussis. If in doubt, please ask your doctor to check.-----------------------------------------------------------------------------------------------------------------------------------------
Option 1: If the child care group includes a child <12 months who have received fewer than 3 effective doses of pertussis vaccine
Small children can have severe disease, and we recommend that all children in the class take special antibiotics to help prevent pertussis. While the pertussis vaccination greatly reduces the risk of disease, there is still a chance your child could get pertussis even if they have been fully vaccinated. Given that there is a high chance your child has been exposed to the disease while at childcare, we recommend that he/she takes antibiotics even if he/she has been vaccinated. Antibiotics have been arranged through [the child’s own doctor, or other arrangement].
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Option 2: If the child care group does not have a child < 12 months who have received fewer than 3 effective doses of pertussis vaccine
We recommend that children who are not fully vaccinated against pertussis in the class take special antibiotics to help prevent infection.
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If your child is unable to take the antibiotics and is not fully vaccinated, he/she should not attend the [facility] until [14 days after exposure].
Need more information?
For more information, please see the attached Pertussis Fact sheet, or call <name> at the Public Health Unit on <phone>.Yours sincerely
Director, Public Health Unit
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