Poliomyelitis (polio) vaccine: Canadian Immunization Guide

# Key information
What
- Polio remains endemic in two countries - Afghanistan and Pakistan; additional countries are known or suspected of having re-established transmission of poliovirus. Several other countries have ongoing outbreaks due to importations of poliovirus.
- Children less than 5 years of age are more susceptible to polio infection.
- Inactivated poliomyelitis - containing vaccines (IPV) produce immunity in over 95% of vaccinees after 3 doses and in close to 100% following a booster dose.
- Adverse events following IPV vaccine are usually limited to mild injection site reactions.
- Oral poliomyelitis vaccine (OPV) is not used in Canada.
Who
- IPV-containing vaccine is recommended for:
	+ routine immunization of infants and children
	+ unimmunized or incompletely immunized children
	+ unimmunized adults
	+ as a booster dose for adults previously immunized against polio and at increased risk of polio exposure
How
- Routine polio immunization of infants and children: administer DTaP-IPV-Hib vaccine at 2, 4, 6 and 12 to 23 months of age (generally given at 18 months of age). If infant immunization for hepatitis B is undertaken, DTaP-HB-IPV-Hib vaccine may be used. Subsequently, administer a booster dose of either DTaP-IPV or Tdap-IPV vaccine at 4 to 6 years of age (school entry).
- Unimmunized or incompletely immunized children should have their vaccine series completed with IPV- containing vaccine as appropriate for age.
- Adults previously unimmunized with polio vaccine: administer a primary series of IPV-containing vaccine if a primary series of tetanus toxoid-containing vaccine is being given or if the adult is at increased risk for exposure to poliovirus; otherwise, administer polio in a combination vaccine with routine tetanus and diphtheria booster doses.
- Adults previously immunized with polio vaccine: for those at increased risk of exposure to polio (e.g., those travelling to, or planning to work in areas that have wild polio or vaccine-derived polio outbreaks), a single lifetime booster dose of IPV-containing vaccine is recommended.
- IPV-containing vaccines may be administered concomitantly with routine vaccines at different injection sites using separate needles and syringes.
Why
- Until polio eradication has been achieved globally, there remains a small risk of contracting polio with travel to countries with circulating poliovirus (endemic or outbreak) and importation of polio into Canada.
- The case fatality rate for paralytic polio is 2% to 5% among children and 15% to 30% for adults.

# Epidemiology

## Disease description

### Infectious agent
Polio is caused by poliovirus, a member of the enterovirus subgroup of the *Picornaviridae- family.

### Reservoir
Humans

### Transmission
Transmission of poliovirus occurs predominantly through the fecal-oral route. Respiratory spread may rarely occur. The incubation period for polio is 3 to 6 days for onset of non-specific symptoms. In those that progress to paralysis, this occurs in 7 to 21 days from exposure (can range up to 35 days). Communicability is greatest around the onset of illness when the virus is present in high concentrations in the throat and feces. Poliovirus can remain in feces for 3 to 6 weeks. In persons who have received oral polio vaccine (OPV), poliovirus can be present in the throat for 1 to 2 weeks following immunization and can remain in feces for several weeks. In rare cases, including among immunocompromised persons, poliovirus (from natural infection or OPV vaccine) can be excreted for prolonged periods of time (from greater than 6 months to a number of years).

### Risk factors
Polio infections are more common in children less than 5 years of age; however, any person who is not immune to poliovirus, regardless of age, can become infected.

### Seasonal and temporal patterns
In temperate climates, polio infection generally increases in the late summer and autumn months.

### Spectrum of clinical illness
Most polio infections (approximately 75%) are asymptomatic. In symptomatic persons, initial symptoms occur 3 to 6 days after exposure to the virus and include fever, fatigue, headache and vomiting. With increased disease severity, severe muscle pain and stiffness of the neck and back with or without paralysis may occur. Although paralysis is the most visible sign of polio infection, less than 1% of cases result in paralysis. The case fatality ratio for paralytic polio ranges from 2% to 5% among children and 15% to 30% for adults.

## Disease distribution
The incidence of polio in Canada was dramatically reduced by the introduction of immunization programs in the 1950s. In Canada, after many years of use, the OPV was replaced with an IPV in 1995/1996. The last indigenous case of wild poliovirus in Canada was in 1977. In 1994, Canada was certified as being free of wild poliovirus by the World Health Organization (WHO), with exceptionally rare cases of paralytic polio being associated with importations of wild or vaccine-derived poliovirus. The last nationally reported case of paralytic polio occurred in 1995 and was related to OPV receipt. More information on  and  in Canada can be found on PHAC's website.
Currently only type 1 wild poliovirus remains endemic in two countries globally. Type 2 wild poliovirus was declared eradicated in September 2015, with the last virus detected in 1999. Type 3 wild poliovirus was declared eradicated in October 2019. It was last detected in November 2012.
In April 2016, WHO coordinated a synchronized global withdrawal of the trivalent oral polio vaccine (tOPV) which contained the Sabin 2 strain of the virus. Since then, countries incorporating oral poliovirus routine immunization programs have been using a bivalent oral polio vaccine (bOPV) containing the attenuated Sabin 1 and 3 strains. Despite this change, circulating vaccine-derived poliovirus 2 (cVDPV2) outbreaks continue to occur, primarily due to inadequate vaccine coverage and response efforts to contain the outbreaks.

# Preparations authorized for use in Canada

## Poliomyelitis-containing vaccines
- ADACEL-POLIO (adsorbed vaccine containing tetanus toxoid, reduced diphtheria toxoid and reduced acellular pertussis vaccine combined with inactivated poliomyelitis vaccine), Sanofi Pasteur Ltd. (Tdap-IPV)
- BOOSTRIX-POLIO (adsorbed vaccine containing tetanus toxoid, reduced diphtheria toxoid and reduced acellular pertussis vaccine combined with inactivated poliomyelitis vaccine), GlaxoSmithKline Inc. (Tdap-IPV)
- IMOVAXPolio (inactivated poliomyelitis vaccine (vero cell origin), Sanofi Pasteur SA (manufacturer), Sanofi Pasteur Ltd. (distributor). (IPV)
- INFANRIX-IPV/Hib (adsorbed vaccine containing diphtheria and tetanus toxoids, acellular pertussis, inactivated poliomyelitis and conjugated *Haemophilus influenzae- type b vaccine), GlaxoSmithKline Inc. (DTaP-IPV-Hib)
- INFANRIX hexaTM (adsorbed vaccine containing diphtheria and tetanus toxoids, acellular pertussis, hepatitis B (recombinant), inactivated poliomyelitis and conjugated *Haemophilus influenzae- type b vaccine), GlaxoSmithKline Inc. (DTaP-HB-IPV-Hib)
- PEDIACEL (adsorbed vaccine containing diphtheria and tetanus toxoids and acellular pertussis vaccine combined with inactivated poliomyelitis vaccine and *Haemophilus influenzae- type b conjugate vaccine), Sanofi Pasteur Ltd. (DTaP-IPV-Hib)
- QUADRACEL (adsorbed vaccine containing diphtheria and tetanus toxoids and acellular pertussis vaccine combined with inactivated poliomyelitis vaccine), Sanofi Pasteur Ltd. (DTaP-IPV)
IPV contains three types of inactivated poliovirus (trivalent) and is available as a single vaccine or as a combination vaccine. Live attenuated OPV is no longer recommended or available in Canada because most cases of paralytic polio from 1980 to 1995 were associated with OPV vaccine. bOPV vaccine continues to be widely used internationally. Monovalent OPVs (e.g., mOPV1, mOPV2, mOPV3, and novel OPV2 ) are also available and used for outbreak management.
For complete prescribing information, consult the product leaflet or information contained within Health Canada's authorized product monographs available through the . Refer to Table 1 in  in Part 1 for a list of all vaccines available for use in Canada and their contents.

# Efficacy, effectiveness and immunogenicity
IPV-containing vaccines produce immunity to all three types of poliovirus in over 95% of vaccinees following three doses of vaccine, and in close to 100% following a booster dose. Seroconversion rates are lower if the minimum age and minimum intervals for vaccine administration are used in infants less than 6 months of age.

# Recommendations for use

## Infants and children (2 months to 17 years of age)
An IPV-containing vaccine is recommended for routine infant immunization beginning at 2 months of age. DTaP-IPV (with or without Hib) vaccine is authorized for use in children less than 7 years of age. DTaP-HB-IPV-Hib vaccine is authorized for use in children 6 weeks to 23 months of age and may be given to children aged 24 months to less than 7 years, if necessary. DTaP-IPV or Tdap-IPV vaccine should be used as the booster dose for children at 4 to 6 years of age. Children 7 years of age and older should receive IPV vaccine or the adolescent/adult formulation of the diphtheria-tetanus-pertussis-polio-containing vaccine (Tdap-IPV). Tdap-IPV vaccine contains less pertussis and diphtheria toxoid than vaccines given to younger children and is less likely to cause reactions in older children. Tdap vaccine is generally administered to adolescents at 14 to 16 years of age as the first 10-year booster dose; however, Tdap-IPV vaccine should be used if IPV vaccine is also indicated.

## Adults (18 years of age and older)
Similar to vaccination of children, vaccination of adults is recommended to prevent polio. A complete series of IPV-containing vaccine is recommended for previously unimmunized adults who are also receiving a primary series of tetanus toxoid-containing vaccine. For other adults who are only unvaccinated against polio, vaccination efforts should be focused on those who are at increased risk of exposure to polioviruses (refer to ). Adults who are unvaccinated against polio but who do not need a primary series of tetanus and diphtheria toxoid-containing vaccine and who are not at increased risk of exposure can be provided with polio vaccinations when tetanus and diphtheria toxoid-containing vaccine booster doses are due.
Adults previously immunized with polio vaccine: for those at increased risk of exposure to polio (e.g., those travelling to, or planning to work in areas that have wild polio or vaccine-derived polio outbreaks) a single lifetime booster dose of IPV-containing vaccine is recommended (refer to ).
- Travellers to, or persons receiving travellers from, areas where poliovirus is known or suspected to be circulating
- Members of communities or specific population groups with disease caused by polio
- Health care workers who have close contact with patients who might be excreting wild type or vaccine type poliovirus
- People who come in close contact with those who may be excreting poliovirus (e.g., people working with refugees, or the military and people on humanitarian missions in endemic countries)
- Laboratory workers handling specimens that may contain poliovirus
- Family or close contacts of internationally adopted infants who may have been or will be vaccinated with OPV vaccine

## Persons with inadequate immunization records
Children and adults lacking adequate documentation of immunization should be considered unimmunized and started on an immunization schedule appropriate for their age and risk factors. Children who were not vaccinated against all three types of poliovirus (e.g., received bOPV vaccine after April 2016 without receipt of at least two doses of mOPV2, nOPV2 or IPV) remain at risk of VDPV2 and should be considered incompletely immunized.
If indicated, IPV vaccine can be given to unimmunized or incompletely immunized persons without concern about prior receipt of the polio-containing vaccine, because adverse events associated with repeated immunization with the vaccine have not been demonstrated. Refer to  in Part 4 for additional information. Refer to  in Part 3 for additional general information.
Fractional IPV (fIPV) corresponds to the intradermal administration of one fifth (1/5) of the regular IPV dose. fIPV has been used internationally (routine or outbreak immunization) in a context of IPV supply shortages. fIPV has been shown to offer adequate protection against polio and, as a result, the WHO Strategic Advisory Group of Experts on Immunization (SAGE) recommended a two-dose fIPV schedule to countries if needed.

## Pregnancy and breastfeeding
IPV vaccine may be considered for pregnant people who require immediate protection and are at increased risk of exposure to wild poliovirus (refer to ). There is no evidence to suggest a risk to the fetus or to the pregnancy from immunization of the pregnant person with inactivated vaccines, such as IPV vaccine. Refer to  in Part 3 for additional general information.

## Infants born prematurely
Premature infants in stable clinical condition should be immunized with an IPV-containing vaccine at the same chronological age and according to the same schedule as full-term infants. Infants born prematurely (especially those weighing less than 1,500 grams at birth) are at higher risk of apnea and bradycardia following vaccination. Hospitalized premature infants should have continuous cardiac and respiratory monitoring for 48 hours after their first immunization. Refer to  in Part 3 for additional general information.

## Persons/residents in health care institutions
Residents of long-term care facilities should receive all routine immunizations appropriate for their age and risk factors, including IPV-containing vaccine. Refer to  in Part 3 for additional general information.

## Immunocompromised persons
IPV-containing vaccines may be administered to immunocompromised persons. When considering immunization of an immunocompromised person, consultation with the individual's attending physician may be of assistance in addition to the guidance provided in Immunocompromised persons in  and  in Part 4. For complex cases, referral to a physician with expertise in immunization or immunodeficiency is advised.

## Persons with chronic diseases

## Travellers
Unimmunized or incompletely immunized travellers should receive an IPV-containing vaccine as appropriate for age, particularly if they are children, or if travelling to areas where poliovirus is known or suspected to be circulating. Previously unimmunized children travelling to areas where poliovirus is known or suspected to be circulating should start a primary series of an IPV-containing vaccine, with consideration given to an accelerated schedule (refer to ). For infants embarking on travel, the first dose of DTaP-IPV-Hib or DTaP-HB-IPV-Hib vaccine can be given at 6 weeks of age. If IPV vaccine is not available in the region to which the child is travelling, children may complete their series with either IPV or bOPV vaccine while travelling. However, it is necessary to ensure that all IPV vaccine doses are received following return to Canada, since children with an incomplete schedule or those receiving bOPV only remain at risk of VDPV2. Parents of children receiving OPV vaccine should be informed that infants can excrete attenuated (vaccine-derived) poliovirus for up to 5 days following vaccination, so household contacts and caregivers of these infant should have up-to-date polio immunization. For vaccinees who are immunocompromised, the period of vaccine virus excretion might be longer. People should be instructed to wash their hands carefully after changing diapers. Household contacts who are vaccinated with OPV should not have contact with immunocompromised persons for six weeks after receipt of OPV. There is also a small risk of OPV vaccine-associated paralytic polio (approximately 1 per 2.4 million doses distributed).
Children with a complete primary series do not require additional doses of IPV vaccine before travelling. For adults previously immunized against polio, a single lifetime dose of polio-containing vaccine is recommended for travellers at increased risk of exposure to polio (e.g., military personnel, workers in refugee camps in endemic areas, or travellers to areas where poliovirus is known or suspected to be circulating) (refer to ). Refer to the Committee to Advise on Tropical Medicine and Travel (CATMAT)  for more information.

## Persons new to Canada
Health care providers who see people newly arrived in Canada should review the immunization status and update immunization for these individuals if needed. Previous poliovirus vaccination is only considered valid if individuals have documented proof of age-appropriate complete immunization against the three types of poliovirus (e.g., receipt of IPV, fIPV, tOPV, or combination of bOPV and mOPV2). Refer to  for more information.
Children who have received one or more doses of polio vaccine before arriving in Canada should have their vaccine series completed with IPV-containing vaccine as appropriate for age. Children who were not vaccinated against all three types of poliovirus (e.g., received bOPV vaccine after April 2016 without receipt of at least two doses of mOPV2, nOPV2 or IPV) remain at risk of infection. Those who received bOPV only should receive a complete age-appropriate IPV series to be optimally protected against polio, including VDPV2.
Similar to children, vaccination of adults is recommended to prevent the polio. A complete series of IPV-containing vaccine is recommended for previously unimmunized adults who are also receiving a primary series of tetanus toxoid-containing vaccine. Adults previously immunized with polio vaccine and at increased risk of exposure to polio should receive a single lifetime booster dose of IPV-containing vaccine. Refer to  in Part 3 for additional general information.

## Workers
Workers who need a primary series of tetanus and diphtheria toxoid-containing vaccine should also receive IPV-containing vaccine if unvaccinated against polio. For other workers who are unvaccinated against polio, vaccination efforts should be focused on those who are at increased risk of exposure to polioviruses as identified in . If previously vaccinated with a primary series of tetanus and diphtheria toxoid-containing vaccine and not in an increased risk group (refer to ), adults unvaccinated against polio can receive IPV-containing vaccine when due for their next tetanus and diphtheria booster. Refer to  in Part 3 for additional general information.

# Vaccine administration

## Dose, route of administration, and schedule

### Dose
Each dose of IPV-containing vaccine is 0.5 mL.

### Route of administration
Combination vaccines containing IPV vaccine must be administered intramuscularly. IPV vaccine when given as a separate vaccine, should be administered subcutaneously. Refer to  in Part 1 for additional information.

### Schedule

### Infants and children (2 months to 6 years of age)
Routine polio immunization of infants: DTaP-IPV-Hib vaccine should be given at 2, 4, 6 and 12 to 23 months of age (generally given at 18 months of age).
If infant immunization for hepatitis B is undertaken, DTaP-HB-IPV-Hib vaccine may be used as an alternative to separately administered hepatitis B and DTaP-IPV-Hib vaccines. DTaP-HB-IPV-Hib vaccine is authorized for use in children 6 weeks to 23 months of age and may be given to children aged 24 months to less than 7 years, if necessary. DTaP-HB-IPV-Hib vaccine may be given at 2, 4, 6 and 12 to 23 months of age, but the fourth dose is unlikely to provide significant additional hepatitis B protection and will increase cost. Alternative schedules may be used as follow:
- DTaP-HB-IPV-Hib vaccine (2, 4 and 6 months of age) with DTaP-IPV-Hib vaccine at 12 to 23 months of age
- DTaP-HB-IPV-Hib vaccine (2, 4 and 12 to 23 months of age) with DTaP-IPV-Hib vaccine at 6 months of age.
A dose of IPV-containing vaccine is not required at 6 months of age for a complete primary series of polio vaccine; however, it is acceptable to give the additional dose of IPV vaccine in a combination vaccine for convenience of administration.
If rapid protection is required for an infant, the first dose of DTaP-IPV-Hib or DTaP-HB-IPV-Hib vaccine can be given at 6 weeks of age. The first three doses may be administered at intervals of 4 weeks and, optimally, the fourth dose given 12 months after the third dose. The fourth dose may be given at a minimum interval of 6 months after the third dose in certain situations (e.g., travel) but must be administered at or after 12 months of age for sustained immunity.
Children less than 7 years of age, not immunized in infancy: should receive three doses of DTaP-IPV (with or without Hib) vaccine with an interval of 8 weeks between doses, followed by a dose of DTaP-IPV vaccine 6 to 12 months after the third dose. A booster dose of either DTaP-IPV or Tdap-IPV vaccine should be administered at 4 to 6 years of age (school entry). The booster dose at 4 to 6 years of age is not required if the fourth dose of tetanus-toxoid containing vaccine was administered after the fourth birthday.
If rapid protection is required for a child less than 7 years of age not immunized in infancy, with imminent exposure to circulating poliovirus (e.g., during an outbreak or because of travel), the first three doses of vaccine may be administered at intervals of 4 weeks and, optimally, the fourth dose given 12 months after the third dose. The fourth dose may be given at a minimum interval of 6 months after the third dose in certain situations (e.g., travel).
Children (4 years of age and older) not immunized against polio in infancy and not requiring the additional antigens in combination vaccine should receive two doses of IPV vaccine, given 4 to 8 weeks apart, followed by a third dose administered 6 to 12 months after the second dose.
Children who received a primary series of IPV-containing vaccine and a booster dose 6-12 months later as outlined above, should receive a booster dose of either DTaP-IPV or Tdap-IPV vaccine at 4 to 6 years of age (school entry). The booster dose at 4 to 6 years of age is not required if the third dose of IPV-containing vaccine was administered after the fourth birthday. A dose of IPV-containing vaccine should be administered at 4 to 6 years of age, regardless of the number doses of IPV and tOPV vaccine administered prior to 4 years of age.

### Children and adolescents (7 years to 17 years of age)
For children and adolescents not previously immunized with tetanus, diphtheria and polio, refer to  or  in Part 4. Children 7 years of age and older needing only polio protection, should receive 2 doses of IPV-containing vaccine, given 4 to 8 weeks apart, followed by a third dose administered 6 to 12 months after the second dose.

### Adults (18 years of age and older)
For adults not previously immunized with tetanus, diphtheria and polio, refer to  or  in Part 4. Adults at increased risk for polio who only need polio protection, should receive two doses of IPV-containing vaccine, given 4 to 8 weeks apart, followed by a third dose 6 to 12 months after the second dose. Adults who are unimmunized against polio but are not at increased risk and have had a primary series of tetanus and diphtheria containing vaccine, should receive IPV-containing vaccine as part of their next tetanus and diphtheria booster.

## Booster doses and re-immunization
The preschool booster dose of either DTaP-IPV or Tdap-IPV vaccine should be administered at 4 to 6 years of age. For adults previously immunized against polio, a single lifetime booster dose of IPV-containing vaccine is recommended for those at increased risk of exposure to polio (e.g., military personnel, workers in refugee camps in endemic areas, travellers to areas where poliovirus is known or suspected to be circulating) (refer to ).

# Serologic testing
Serologic testing is not recommended before or after receiving IPV vaccine.

# Storage requirements
IPV-containing vaccines should be stored in a refrigerator at +2C to +8C and not frozen. Refer to  in Part 1 for additional general information.

# Simultaneous administration with other vaccines
IPV-containing vaccines may be administered concomitantly with routine vaccines at different injection sites using separate needles and syringes. Refer to  in Part 1 for additional general information.

# Vaccine safety and adverse events

## Common and local adverse events
Adverse events following IPV vaccine are usually limited to mild injection site reactions.

## Less common and serious or severe adverse events
Serious adverse events are rare following immunization with IPV-containing vaccine and, in most cases, data are insufficient to determine a causal association. Anaphylaxis following vaccination with IPV-containing vaccine may occur, but is very rare.

## Guidance on reporting Adverse Events Following Immunization (AEFI)
Vaccine providers are asked to report, through local public health officials, any serious or unexpected adverse event felt to be temporally related to vaccination. An unexpected AEFI is an event that is not listed in available product information but may be due to the immunization, or a change in the frequency of a known AEFI.

## Contraindications and precautions
IPV-containing vaccines are contraindicated in persons with a history of anaphylaxis after previous administration of the vaccine and in persons with proven immediate or anaphylactic hypersensitivity to any component of the vaccine or its container (e.g. latex). Refer to Table 1 in  in Part 1 for a list of all vaccines available for use in Canada and their contents. For IPV-containing vaccines, potential allergens include:
- ADACEL-POLIO: neomycin, polymyxin B, streptomycin
- BOOSTRIX-POLIO: latex in plunger stopper of pre-filled syringe, neomycin, polymyxin B
- IMOVAX-POLIO: neomycin, polymyxin B, streptomycin
- INFANRIX hexaTM: latex in plunger stopper of pre-filled syringe, neomycin, polymyxin B, yeast
- PEDIACEL: neomycin, polymyxin B, streptomycin
- QUADRACEL: neomycin, polymyxin B
Hypersensitivity to yeast is very rare and a personal history of yeast allergy is not generally reliable. In situations of suspected hypersensitivity or non-anaphylactic allergy to vaccine components, investigation is indicated, which may involve immunization in a controlled setting. Consultation with an allergist is advised.
Administration of IPV-containing vaccine should be postponed in persons with moderate or severe acute illness. Persons with minor acute illness (with or without fever) may be vaccinated.

# Other considerations

## Interchangeability of vaccines
The primary series of three doses of IPV-containing vaccine should be completed with an appropriate vaccine from the same manufacturer whenever possible. However, if the original vaccine is unknown or unavailable, an alternative combination vaccine from a different manufacturer may be used to complete the primary series. On the basis of expert opinion, an appropriate product from any manufacturer can be used for all booster doses. Refer to  in Part 1 for additional general information.