Surveillance

Canadian Paediatric Surveillance Program
Acute Flaccid Paralysis

Principal investigator

Shalini Desai, MD, FRCPC, Centre for Immunization and Respiratory Infectious Diseases, Public Health Agency of Canada; shalini.desai@phac-aspc.gc.ca

Study publications/presentations

CPSP resource

• Stool Cultures for AFP Surveillance (Don’t "pooh-pooh" the idea)

CPSP highlights

• What does the CPSP have to do with public health?
• CPSP 2002 Results: What have we learned?
• Reaching the target for global polio eradication – almost there!
• Unravelling an acute flaccid paralysis event
• Don’t ‘pooh-pooh’ stool cultures for surveillance of acute flaccid paralysis

Publications

• The Canadian Paediatric Surveillance Program: Beyond collecting numbers
• Protocol for the investigation of acute flaccid paralysis and suspected paralytic poliomyelitis

Presentations

• Rare diseases research through surveillance: The Canadian experience.  
• Public health implications of the Candadian Paediatric Surveillance Program.  
• International Network of Paediatric Surveillance Units: A child's global village.  
• The Canadian Paediatric Surveillance Program (CPSP): An epidemiological tool in action
• Canadian Paediatric Surveillance Program (CPSP): Congenital Rubella Syndrome (CRS), Subacute Sclerosing Panencephalitis (SSPE) and Acute Flaccid Paralysis (AFP): Relationship of frequency to vaccine status
• Canadian Paediatric Surveillance Program (CPSP): Clinical implications

Background

The last case of indigenous wild paralytic poliomyelitis in Canada occurred in 1977. Paralytic cases in 1978/1979 (11 cases) and 1988 (one case) occurred as a result of wild virus importation. Two other instances of wild virus importation, in 1993 and 1996, resulted in very limited secondary transmission and no associated paralytic illness. Continued surveillance for poliomyelitis is essential because of the risk of wild virus importation from polio-endemic regions, a risk that remains until global polio eradication is achieved. Active surveillance of acute flaccid paralysis (AFP) in children less than 15 years old played a pivotal role in monitoring suspected cases of paralytic poliomyelitis and provided evidence of the elimination of indigenous wild poliovirus transmission in Canada and the rest of the Americas. This led to the certification of polio eradication in the American Region in September 1994. AFP surveillance continues to be a critical component of the World Health Organization (WHO) global polio eradication campaign. WHO estimates a background annual incidence of at least 1 case of AFP per 100,000 population less than 15 years old, in the absence of wild poliovirus transmission. This rate can be used to evaluate the sensitivity of AFP surveillance activities.

In Canada, active AFP surveillance was initiated in 1991 through the Immunization Monitoring Program, ACTive (IMPACT) network comprising 11 paediatric centres across Canada representing 85% of the Canadian paediatric tertiary care beds. Since 1996, AFP surveillance has been carried out through the Canadian Paediatric Surveillance Program (CPSP) based on voluntary reporting by paediatricians as well as active monitoring of admissions to IMPACT centres. AFP surveillance also provides an opportunity to develop further studies of the etiology of Guillain-Barré syndrome in children.

Methods

Aggregate monthly reports of AFP are followed up to obtain case-specific clinical, laboratory and epidemiological information using a standardised form. Cases are reviewed to determine compatibility with national surveillance criteria for paralytic poliomyelitis. Those cases compatible with paralytic poliomyelitis are referred to the national Working Group on Polio Eradication for further evaluation to confirm or rule out paralytic poliomyelitis. A protocol for the investigation of suspected cases of paralytic poliomyelitis and AFP cases was published in 1997 and emphasises that in all cases of acute flaccid paralysis, a stool specimen should be collected within two weeks of onset of paralysis and examined for poliovirus.

Objectives

• To identify AFP cases (including Guillain-Barré syndrome) in children less than 15 years old.
• To investigate all reported cases for evidence to rule out or confirm paralytic poliomyelitis.

Case definition

Acute onset of focal weakness or paralysis characterised as flaccid (reduced tone) without other obvious cause (e.g., trauma) in children less than 15 years old. Transient weakness (e.g., post-ictal weakness) should not be reported.

Duration

January 1996 to December 2013

Expected number of cases

One case per 100,000 population less than 15 years old (~ 60 cases) per year

Ethical approval

Canadian Paediatric Society (CPS) Bioethics Committee

Date for analysis and publication

Quarterly and annual reports are distributed to primary stakeholders, including participating paediatricians, provincial and territorial epidemiologists, Centre for Infectious Disease Prevention and Control, and the Working Group on Polio Eradication.

Ad hoc reports and other publications will be at the discretion of the Division of Immunization, Bureau of Infectious Diseases, Centre for Infectious Disease Prevention and Control, Population and Public Health Branch and the Working Group on Polio Eradication. Data may be published in conjunction with data from other surveillance activities for AFP and poliomyelitis.