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Poliomyelitis

Queensland Health Guidelines for Public Health Units

Revision History

VersionDateChanges
1.0January 2011Full revision of guideline
2.0September 2014Full revision of guideline
   

To be read in conjunction with acute flaccid paralysis (AFP) and EV71 guidelines and An Acute Flaccid Paralysis and Poliomyelitis Response Plan for Australia.

Infectious Agent

The infectious agents are polioviruses types 1, 2 or 3 either wild type, vaccine derived, or vaccine associated (Sabin-like).

Notification Criteria

Clinical Evidence

Paralytic infection
Any child under 15 years of age with acute flaccid paralysis (AFP) [1] (including Guillain-BarrĂ© syndrome) or any person of any age with paralytic illness if polio is suspected. 

For a case to be classified as vaccine-associated paralytic poliomyelitis (VAPP) the determination must be made by the Polio Expert Committee (PEC), a subcommittee of CDNA. 

NB: cases with illness not consistent with AFP, including asymptomatic cases, should be classified using the non-paralytic infection case definition, which requires laboratory definitive evidence only. Only AFP is clinically notifiable under the Public Health Act 2005.    

Paralytic Laboratory definitive evidence

Wild poliovirus infectionIsolation of wild poliovirus (confirmed in the National Enterovirus Reference Laboratory)
OR
detection of wild poliovirus by nucleic acid testing (confirmed in the National Enterovirus Reference Laboratory).

Vaccine-associated paralytic poliomyelitis (VAPP)Isolation of Sabin-like poliovirus (confirmed in the National Enterovirus Reference Laboratory)
OR
detection of Sabin-like poliovirus by nucleic acid testing (confirmed in the National Enterovirus Reference Laboratory).

Vaccine derived poliovirus (VDPV) infectionIsolation of poliovirus (confirmed in the National Enterovirus Reference Laboratory) OR detection of poliovirus by nucleic acid testing (confirmed in the National Enterovirus Reference Laboratory), characterised as a vaccine derived poliovirus according to the current definition of the World Health Organization (reported by the National Enterovirus Reference Laboratory).

Non-paralytic laboratory definitive evidence

Wild poliovirus infectionAs for paralytic laboratory definitive evidence

Sabin-like poliovirus infectionIsolation of Sabin-like poliovirus (confirmed in the National Enterovirus Reference Laboratory) OR detection of Sabin-like poliovirus by nucleic acid testing (confirmed in the National Enterovirus Reference Laboratory) except where there has been vaccination with Sabin oral polio vaccine in the six weeks# prior to the date of specimen collection.

# Note: This period may be longer for immunocompromised individuals

Vaccine derived poliovirus (VDPV) infection
As for paralytic laboratory definitive evidence

[1] AFP syndrome is characterised by rapid onset of weakness of an individual’s extremities, often including weakness of the muscles of respiration and swallowing, progressing to maximum severity within 1-10 days. The term “flaccid” indicates the absence of spasticity or other signs of disordered central nervous system (CNS) motor tracts such as hyperflexia, clonus, or extensor plantar responses. (Excerpt from Acute onset flaccid paralysis; World Health Organization 1993; WHO/MNH/EPI/93.3. Geneva)

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Notification Procedure

Attending Medical Practitioners/Medical Superintendents (or delegates)To notify on clinical diagnosis of AFP by telephone or facsimile to the local public health unit. 

Pathology LaboratoriesTo notify (i) on receipt of request for examination and (ii) upon confirmation of diagnosis by telephone or facsimile.

The public health unit (PHU)
Should immediately notify the Communicable Diseases Unit (CDU) of a clinical diagnosis of AFP by telephone with follow-up email to Senior Director CDU.  If telephone contact is not possible, notify Senior Director CDU by email with the subject line clearly noting that the email is for urgent attention.

Reporting to NOCS

Report both confirmed and probable cases.

Confirmed caseA confirmed case of poliomyelitis (paralytic infection) requires laboratory definitive evidence AND clinical evidence. 

A confirmed case of poliomyelitis (non-paralytic infection) requires laboratory definitive evidence only.  This case definition should be used for asymptomatic patients or patients with illness not consistent with acute flaccid paralysis

NB: For a case to be classified as VAPP the determination must be made by the Polio Expert Committee (a subcommittee of CDNA).

Probable caseA probable case of poliomyelitis (paralytic infection) requires clinical evidence AND the case not discarded as non-polio paralytic illness by the Polio Expert Committee.

Suspected caseA suspected case of poliomyelitis (paralytic infection) requires clinical evidence AND either travel to an endemic/epidemic country or household contact with someone with recent travel to an endemic/epidemic country AND evidence of lack of immunity (i.e. history of inadequate vaccination).

Objectives of surveillance
To identify cases so that appropriate public health measures can be taken.

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Public Health Significance and Occurrence

Prior to the advent of immunisation, poliomyelitis occurred worldwide. Now, due to the global effort to eradicate polio, the number of polio cases have reduced from 350 000 cases in 1988 to 406 reported cases in 2013. In 2014 only three countries – Nigeria, Pakistan and Afghanistan. remained polio-endemic, down from 125 countries in 1988[2]. However, despite these efforts in the first half of 2014 13 cases of wild type polio were reported in non-endemic countries in Africa and the Middle East. In industrialised countries, cases of poliomyelitis are occasionally recognised among unimmunised tourists and unimmunised immigrants revisiting their country of origin. 

Australia had its last cases of locally acquired wild poliovirus infections in 1972.  In 2007 a  22 year old overseas student  was diagnosed with type 1 wild poliovirus, acquired in Pakistan. In May 2014 a probable case was diagnosed in a Victorian man who had returned to Australia from Africa.  As acquisition occurred overseas, Australia maintained its WHO polio free status. 

All cases of poliomyelitis in Australia need immediate investigation. Any case due to wild poliovirus or VDPV should be regarded as a public health emergency. Any locally acquired case due to wild poliovirus would be of particular concern since each case of paralytic infection probably represents 100-200 infected persons.

The Australian National Immunisation Program moved from oral poliomyelitis vaccine (OPV) to injectable polio vaccine (IPV) in November 2005.  The major advantage of IPV over OPV is that it does not cause VAPP.  OPV is no longer available in Australia.

It has been estimated that one case of VAPP occurs for every 2.4 million doses of oral OPV [3]. VAPP may develop either in the vaccine recipient or a close contact. The last reported case of VAPP in Australia was in an unvaccinated mother of a recently vaccinated infant whose onset of illness was in December 1994. A VAPP case could still occur in Australia from importation of Sabin-like viruses. However, the chance of further linked cases would be remote.

Potential scenarios for a poliomyelitis outbreak in Australia include the following:

  • Importation of wild poliovirus from an endemic country or a country with recently imported wild poliovirus
  • Importation of VDPV from a country that has circulating VDPV
  • Laboratory acquisition.

[2] http://www.who.int/mediacentre/factsheets/fs114/en/

[3] http://www.who.int/ith/vaccines/polio/en/

Clinical Features

Poliomyelitis may be clinically inapparent or associated with non-specific fever. If symptoms occur, they may include headache, gastrointestinal disturbance, malaise, and stiffness of the neck and back, with or without paralysis. Aseptic meningitis may also occur. Paralytic poliomyelitis is associated with fever at onset, is asymmetric and evolves over 3 or 4 days. It may be spinal (79%), bulbar (2%), or bulbospinal (19%) The case fatality rate in paralytic poliomyelitis is 2-5% in children, 15-30% in adults and up to 75% overall in bulbar poliomyelitis. The asymptomatic infection to paralytic infection ratio may be as high as 1000:1 in children and 75:1 in adults depending on the poliovirus type and social and environmental conditions [4].

[4] http://www.immunise.health.gov.au/internet/immunise/publishing.nsf/Content/handbook10-4-14

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Reservoir

Humans, most frequently children with unapparent infection are the reservoir of infection.  Long term carriers of wild type viruses have not been found.

Mode of Transmission

  • Faecal-oral route through direct transmission, especially important where sanitation is poor
  • In rare instances, indirect transmission via milk, foodstuffs and other materials contaminated with faeces
  • Pharyngeal spread via secretions directly or indirectly, more important where there is good sanitation and during epidemics.

Incubation Period

The incubation period ranges from 3 to 21 days.

Period of Communicability

Not accurately known, but for as long as excretion of the virus persists. The virus can be detected in throat secretions 36 hours after exposure and in faeces 72 hours after exposure. It typically persists in throat secretions for approximately one week and faeces for 3 to 6 weeks or longer in immune-compromised individuals. Infected persons are most infectious from 7 to 10 days before, to 7 to 10 days after the onset of symptoms[5]. The vaccine virus may be shed in the faeces for six weeks or more, and for up to several years in immunodeficient subjects.

[5] http://www.immunise.health.gov.au/internet/immunise/publishing.nsf/Content/handbook10-4-14

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Susceptibility and Resistance

In the absence of vaccination, susceptibility to infection is universal, but paralysis occurs only in 1% of infections. Second attacks are rare and are due to infection with a poliovirus of a different type. A full primary course of three IPV injections produces long lasting immunity (both mucosal and humoral) to all three poliovirus types. However IPV produces considerably lower levels of intestinal immunity than OPV. A universal booster dose of IPV is recommended at four years of age with further booster doses desirable every ten years for anyone at particular risk of infection.

Management

Management

A case of poliomyelitis due to wild poliovirus or VDPV is considered a public health emergency. Many people may have been exposed to the virus before a case of AFP is detected.  In the event of a suspected case of poliomyelitis, an urgent statewide outbreak control team (SOCT) should be convened. Confirmation of a case would initiate activation of the national response plan by the Chief Health Officer (CHO), with the involvement of the Communicable Diseases Network Australia (CDNA), Polio Expert Committee (PEC) and the Australian Department of Health and Ageing (DoHA). For further details refer to An Acute Flaccid Paralysis and Poliomyelitis Response Plan for Australia.

The main response to a case of polio will be containment of potential spread, including:

  • Isolation and testing of the index case;
  • Tracing and management of contacts;
  • Targeted vaccination campaign;
  • Education on infection control measures such as hand washing; and
  • Increased surveillance.

The critical factors affecting success of this containment will be:

  • Uptake of vaccine by vulnerable populations;
  • Timely recognition of AFP and reporting as part of active surveillance;
  • Identification of the source of infection: and
  • Detailed epidemiological data and case history to identify cause, potential contacts and at risk populations.

All virology laboratories in the jurisdiction will need to be alerted to the potential for poliovirus to be isolated. It will be necessary to take stool specimens from close contacts of the index case. All clinicians will need to participate in intensified surveillance for AFP and hospital records may need to be checked for potential additional AFP cases. If there is laboratory confirmation that a Sabin-like virus is responsible for the case, epidemiological investigation can be limited to determination of the source, with broader contact tracing and public health management measures unnecessary. 

Cases

Investigation
Investigate all suspected and confirmed cases immediately. In consultation with the attending medical practitioner, ensure laboratory confirmation where relevant, ascertain polio vaccination status, and determine whether the case attends a school or other institution.

Virus isolation should be attempted in every suspected case. All viruses isolated should be identified using not only poliovirus antisera, but also those prepared against most of the other enterovirus serotypes. This will distinguish between poliomyelitis and a poliomyelitis-like illness due to infection by other enteroviruses (see EV71, Botulism and AFP guidelines). 

Faeces should be obtained from all live cases. For hospitalised cases, faeces and throat swabs should be obtained. For meningo-encephalitis, CSF samples should also be obtained. For fatalities, obtain samples of tissues from brain stem, spinal cord, descending colon and serum. 

Specimens for virus isolation should be collected as soon as possible after the onset of illness. Two faecal samples should be taken, 24-48 hours apart. Faeces should be stored at 0 - 8oC. Samples of faeces and viral isolates should be sent to the Royal Brisbane Hospital who will arrange for it to be sent to the National Poliomyelitis Reference Laboratory at the Victorian Infectious Disease Research Laboratory, Melbourne. Specimens must reach VIDRL within 72 hours of collection.  

Determine if likely to be vaccine-associated, based on history of OPV vaccination and timing since last vaccination, or contact with a person recently vaccinated with OPV.

Check vaccination history for all recommended vaccinations, and immunocompetence.

Determine if the infection is locally acquired or imported (laboratory worker or history of overseas travel or contact with persons who have recently travelled to endemic/epidemic areas).

Determine if case has carried out an occupation  associated with risk of spread: commercial food handling, childcare worker, health care worker.

Restriction
Cases (unless confirmed to be vaccine associated) should be isolated in hospital with contact precautions in a single room until no longer infectious as determined by two negative stool samples taken a week apart. Exclude from schools, children's settings or workplaces until receipt of a medical certificate of recovery from infection and two negative stool samples taken a week apart.

Isolation is of little value under home conditions because many household contacts are infected before poliomyelitis is diagnosed.

Disinfection
In communities with modern and adequate sewage disposal, faeces and urine can be discharged directly into the sewers without preliminary disinfection.
Disinfect items contaminated by throat discharges and faeces (refer to Other control measuresDisinfection).

Counselling
The case should be advised of the nature of the infection and its mode of transmission. Advise on catch-up vaccinations where appropriate.

Contacts

Contact tracing
Yes, for confirmed or probable cases due to wild poliovirus or VDPV. For suspected cases depending on SOCT advice

Definition

  • Household contacts (people who lived with the index case and shared a toilet during the infectious period);
  • Toilet contacts (people who shared a toilet with the index case during the infectious period, before the toilet was cleaned);
  • Health care workers (people who cared for the index case during the infectious period) and laboratory workers involved with testing the patient’s specimens;
  • Consumers of food that the index case prepared during the infectious period;

Tracing and management of contacts
Undertake thorough search to ensure early detection of other cases and appropriate treatment/control measures. For identified contacts determine vaccination status, immunocompetence and assess for symptoms of fever, nausea, vomiting, diarrhoea, muscle pains or weakness in the limbs, headache and malaise.        

Previous vaccination or exposure to poliovirus does not necessarily prevent infection and most people are infected with poliovirus without showing symptoms. As such, the following precautions are advised to prevent further transmission of potentially infected contacts.

For further management see table below. A full course of IPV requires three doses a minimum of one month apart. Refer to current edition of The Australian Immunisation Handbook.

NB: in certain situations wider immunisation beyond close contacts may need to be considered.

Families and carers of a patient with polio should observe good sanitation and hand washing. All health care workers, carers and family should be adequately immunised against polio (see Tracing and management of potential contacts below). As most cases of AFP require hospitalisation, health care workers should refer to the Australian Guidelines for the Prevention and Control of Infection in Healthcare [6].

[6] http://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/cd33_infection_control_healthcare_typo_fix_4.2.4_140616.pdf

Management of cases of poliomyelitis due to wild type poliovirus or VDPV and relevant contacts [7

Case management

Isolate in hospital and use contact precautions. A stool specimen should be collected weekly for testing at the NPRL. Isolation should continue until two stool samples taken 7 days apart are negative for poliovirus.

Contact management

Household contacts (people who lived with the index case and shared a toilet during the infectious period)

Quarantine household contacts at home.  Collect stool samples > 3 days after the contact’s first exposure to the index case. Contacts can be released from quarantine when two stool samples taken 24 - 48 hours apart are shown to be negative for poliovirus.  Take a baseline serum sample prior to vaccination with a booster dose of IPV, or if vaccination status is unknown, offer a full course of IPV. Provide education on poliomyelitis, hygiene measures and vaccination.

Toilet contacts* (people who shared a toilet with the index case during the infectious period, before the toilet was cleaned).

Provide education on poliomyelitis disease and hygiene measures.  Check vaccine histories and offer vaccination with IPV.  Offer a single booster dose to previously vaccinated contacts.  Offer a full course of IPV to contacts who have not been previously vaccinated.  Overseas born contacts may not have been fully vaccinated, in which case they should be offered a full course of IPV.

Health care worker contacts (people who cared for the index case during the infectious period) and laboratory workers involved with testing the patient’s specimens

Provide education on poliomyelitis and hygiene measures.  Offer a booster vaccination with IPV for anyone who has not had a booster within the previous 10 years.  For health care workers in close contact with the index case who have no recorded immunisation history, or are not completely vaccinated, take two stool specimens, 24 - 48 hours apart, with the first being taken > 3 days after the contact’s first exposure to the index case and offer a full course of IPV. Ensure that appropriate procedures are followed by laboratory workers during testing of suspect samples.

Contacts who were consumers of food prepared by the index case while infectious

Provide education on poliomyelitis and hygiene measures.  Offer vaccination with IPV as above.

* Tracing of toilet contacts (such as those sharing a section of an aeroplane, workplace or childcare centre with the infected patient) is important to reduce the risk of onward transmission of infection. For containment, the tracing of contacts needs to be more rapid than the spread of the virus. One of the most important reasons for tracing of contacts is to educate them on hygiene and vaccination.

[7] http://www.health.gov.au/internet/main/publishing.nsf/Content/F704FE53A0A23F81CA257BF0001B603E/$File/afp-and-polio-response-plan.pdf

Other control measures

Health Education
A media release is likely to be required for all confirmed cases.

Disinfection
Active disinfection procedures should involve the use of cleaning practices to remove soiling that may harbour and protect viral particles. Effective disinfectants are those which contain free chlorine, such as sodium hypochlorite or bleach, glutaraldehyde solutions, formaldehyde solutions and iodophores. Contact time is also important in inactivating the virus. Laundry should be soaked in chlorine bleach (diluted according to the manufacturer’s instructions) for at least 15 minutes.

Common disinfectants such as 70% ethanol, ispropanol, lysol and quaternary ammonium compounds are not effective against poliovirus. The virus is also resistant to lipid solvents (such as EcoTru® and Dettol®) and is stable in many detergents at room temperature, although temperatures above 60°C for prolonged periods will reduce the infective capability of poliovirus.

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Preventive Measures

Inactivated poliomyelitis vaccine (IPV) or IPV-containing vaccines are recommended for infants from 2 months of age. The primary course consists of 3 separate doses at 2, 4 and 6 months of age. A booster dose is recommended at 4 years of age.

Adult vaccination against poliovirus:  All adults should have completed a full course of poliomyelitis vaccination.  If they have completed such a course, further boosters are unnecessary, unless travelling to an area where poliomyelitis is endemic or epidemic, or if they are a health care worker in possible contact with poliomyelitis cases.  For those exposed to a continuing risk of infection, a single booster dose is desirable every 10 years.

For more information on vaccination and catch-up schedules, refer to the current edition of The Australian Immunisation Handbook.

Booster vaccination for polio prior to departure is recommended for Australian travellers to certain countries (May 2014: Pakistan, Cameroon, Syria, Afghanistan, Equatorial Guinea, Ethiopia, Iraq, Israel, Somalia and Nigeria). Travellers staying four weeks or more are encouraged to carry documentation of their vaccination. Some of these countries will require this documentation prior to departure from that country. Updates via DoH website: http://www.health.gov.au/internet/main/publishing.nsf/Content/ohp-poliomyelitis.htm

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Summary

Prepare a report of the investigation for the Communicable Diseases Unit on request.

References

Australian Department of Health and Ageing, 2008. An Acute Flaccid Paralysis and Poliomyelitis Response Plan for Australia. http://www.health.gov.au/internet/main/publishing.nsf/Content/polio-plan.htm .  Accessed 1/07/14.

Global Polio Eradication Initiative data and monitoring website. http://www.polioeradication.org/casecount.asp .  Accessed 1/07/14.

Heymann D. (Ed), 2008. Control of Communicable Diseases Manual, 19th edition.  American Public Health Association: Washington.

NHMRC. 2013. The Australian Immunisation Handbook, 10th edition. Australian Government: Canberra.  Updated 2014.

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Last updated: 7 August 2017