Vaccine administration practices: Canadian Immunization Guide
For health professionals
Last partial content update (see Table of Updates): May 2023
- May 2023: The section on “Route, site and technique for vaccine administration” was updated to expand on the administration of intradermal injections.
Last complete chapter revision (see Table of Updates): November 2017
On this page
- General considerations
- Pre-vaccination counselling
- Vaccine administration
- Table 2: Vaccine provider administration check list
- Vaccine preparation
- Syringe and needle selection for parenteral vaccines
- Route, site and technique for vaccine administration
- Techniques to decrease immunization injection pain
- Techniques to decrease anxiety and fainting
- Post-vaccination counselling and observation
- Infection prevention and control
- Selected references
Appropriate vaccine administration is essential to the optimal safety and efficacy of vaccines. Vaccine administration practices are based on clinical trials that determine the dose, route and schedule for each vaccine. Professional standards for medication and vaccine administration, and jurisdictional or organizational policies and procedures (if available) also guide vaccination practices.
All vaccine providers should receive education and competency-based training on vaccine administration before providing vaccines to the public. Programs should be in place to monitor the quality of immunization services. For detailed information about the recommended immunization competencies, refer to the Public Health Agency of Canada's Immunization Competencies for Health Professionals.
This chapter provides general guidance regarding vaccine administration practices, for use in conjunction with vaccine manufacturers' instructions as outlined in product leaflets and product monographs; professional standards of practice; and jurisdictional or organizational policies and procedures. The general principles regarding vaccine administration also apply to administration of passive immunizing agents.
Prior to vaccination, the vaccine provider should:
- assess the vaccine recipient's current state of health
- provide information regarding the benefits and risks of receiving or not receiving the vaccine using content and language appropriate to the vaccine recipient or caretaker - refer to Communicating Effectively About Immunization in Part 1 for additional information
- assess contraindications and precautions to receiving the vaccine, including any history of potential immediate or anaphylactic hypersensitivity to a previous dose of the vaccine or to any of the vaccine components - refer to Contraindications, Precautions and Concerns in Part 2 for additional information
- evaluate reactions to previous vaccinations
- discuss frequently occurring minor adverse events and potential rare severe adverse events - refer to vaccine-specific chapters in Part 4 for additional information
- provide an opportunity for the vaccine recipient or guardian to ask questions
- assess that the vaccine recipient is capable of consenting to the procedure or that, when required, an appropriate guardian or substitute decision-maker gives consent
- obtain informed consent
After informed consent is obtained, the vaccine provider should outline the process of vaccine administration and explain positioning procedures. The parent or guardian should hold a child in a position as instructed by the vaccine provider. Failed positioning can result in loss of part or the entire dose, inappropriate depth of injection, or injury to the vaccine recipient or vaccine provider. Refer to Positioning for information about positioning procedures. Refer to Table 4 for education for healthcare providers about immunization pain management strategies. Table 1 provides an example pre-vaccine administration checklist.
|Screening questions for all vaccinesTable 1 - Footnote 1
|Additional screening questions if immunizing with live vaccines
|YesTable 1 - Footnote 5
Vaccines should be administered to the right person using the correct indication, correct vaccine, correct dose, correct route of administration, correct injection site (if applicable) and correct time (schedule), to optimize vaccine effectiveness and to reduce the risk of local reactions or other adverse events. For information on proper documentation of vaccine administration, refer to Immunization Records in Part 1. Table 2 provides an example of a checklist for vaccine administration. Refer to Storage and Handling of Immunizing Agents in Part 1 and vaccine-specific chapters in Part 4 for additional information.
Vaccine inspection and mixing
Before vaccine administration, the vaccine identification label must be checked to ensure selection of the correct vaccine. The expiry date on the vaccine vial and vaccine diluent (if applicable) must be verified to ensure that they have not expired. Vaccines or diluents should not be used beyond their expiration date. Before use, inspect vaccine vials for any irregularities, such as particulate matter, damage or contamination.
Vaccines should be mixed with a careful swirling motion until a uniform suspension is achieved prior to administration. Unless otherwise instructed by the manufacturer, the vaccine should not be shaken before use.
Vaccine providers should adhere to jurisdictional or organizational policies and procedures regarding combining the contents of multi-dose vials. Refer to Storage and Handling of Immunizing Agents in Part 1 for additional information about multi-dose vials.
Vaccines should be reconstituted according to the manufacturers' guidelines, using only the diluent provided by the manufacturer for that purpose, and adhering to jurisdictional or organizational policies and procedures. The diluent should be introduced down the side of the vaccine vial and not directly into the vaccine powder, to avoid foaming or potential denaturing of the vaccine protein. The reconstituted vaccine should be mixed with a careful swirling motion until a uniform suspension is achieved prior to administration, unless otherwise instructed by the manufacturer. Once reconstituted, the vaccine should be administered within the time frame specified in the manufacturer's product information. Refer to Storage and Handling of Immunizing Agents in Part 1 for additional information about vaccine reconstitution.
Vaccine providers should observe strict aseptic technique when reconstituting and drawing vaccine into the syringe. Prior to withdrawal of vaccine into the syringe, the vaccine vial should be uncapped, the stopper wiped with a suitable disinfectant (e.g., isopropyl alcohol) and the stopper allowed to dry.
Refer to Infection Prevention and Control for additional information.
Pre-loading vaccine in syringes
Ideally, a vaccine should be withdrawn from the vial immediately before use by the vaccine provider who is administering the vaccine. Pre-loading syringes with vaccine is strongly discouraged because of the uncertainty of vaccine stability in syringes, risk of contamination, increased potential for vaccine administration errors, and vaccine wastage. Pre-loading of syringes may be considered in the hospital setting if vaccines are drawn up and labelled in the pharmacy, or in an immunization clinic to facilitate efficient administration of a single vaccine to a large number of people; in these circumstances, the following principles should be followed:
- Prior to pre-loading, data should be reviewed on the specified time period for stability of pre-loaded product
- If the vaccine is pre-loaded and administered by different people, a prior agreement on professional accountability should be made
- Only the number of doses required to keep the clinic running efficiently should be drawn up
- Labels should be placed on pre-loaded product to indicate the time by which the vaccine should be used
- All doses should be used as soon as possible
- The cold chain should be maintained at all times
Vaccine providers should adhere to jurisdictional or organizational policies and procedures in regards to pre-loading vaccine in syringes. Refer to Storage and Handling of Immunizing Agents in Part 1 for additional information.
Syringe and needle selection for parenteral vaccines
A separate sterile needle and syringe should be used for each injection. Different vaccines must never be mixed in the same syringe, unless specified by the manufacturer. The use of safety-engineered needles and syringes is preferred and, in many jurisdictions, mandated by law to reduce risk of injury. However, vaccines packaged by the manufacturer in pre-filled syringes should not be transferred to safety-engineered injection devices unless jurisdictional or organizational regulations make this mandatory.
Use a 1 mL or 3 mL syringe, depending on the volume of the vaccine dose.
Appropriate needle selection is important because the immunizing agent must reach the appropriate tissue site (dermis, subcutaneous tissue or muscle) to optimize the immune response and to reduce the risk of injection site reactions. When considering needle length, select a needle that is long enough to reach the tissue site, but not so long as to hit underlying bone. The use of longer needles for intramuscular (IM) injection of vaccine is associated with less injection site redness and swelling than occurs with shorter needles. When needles are too short to reach muscle, vaccine may be inadvertently injected into more superficial tissue such as dermis and subcutaneous tissue, resulting in increased inflammation, induration or granuloma formation. For IM injections, the needle must be long enough to reach muscle but not involve underlying nerves, blood vessels, or bone; the needle should be inserted as far as possible into the muscle. The selection of the right needle should be based on the route of administration, the vaccine recipient's age and size of muscle mass, and the viscosity of the vaccine or passive immunizing agent. Table 3 provides guidelines for needle selection.
|Route of administration
|Age of vaccine recipient
|Site of injection
26 to 27
< 1 year: anterolateral thigh
Intramuscular (IM)Table 3 - Footnote 1
22 to 25Table 3 - Footnote 2
Newborns (<28 days) and preterm infants
2.2 cm to 2.5 cm
1.6 cm to 2.5 cm (⅝ inch to 1 inch)
Anterolateral thighTable 3 - Footnote 3
2.5 cm to 3.2 cm
1.6 cm to 2.5 cm
2.5 cm to 3.2 cm
See weight-based recommendations for adolescents and adults below
2.5 cm to 3.2 cm
Adolescents and adults
For those weighing <130 lbs (<60kg):
Males weighing 130 to 260 lbs (60 to 118kg)
Males weighing >260lbs (118kg) and females weighing >200lbs (90kg):
Filter needles are not recommended for vaccine administration as they may filter out active ingredients such as adjuvants.
Route, site and technique for vaccine administration
Appropriate site selection for vaccine administration is important to avoid inadvertent injection into a blood vessel or injury to a nerve. Vaccines containing adjuvants must be injected intramuscularly. If a vaccine containing an adjuvant is inadvertently injected subcutaneously or intradermally, increased inflammation, induration or granuloma formation may occur.
Injection of a vaccine into an area where lymphatic circulation may be impaired (e.g. local lymphedema, lymphangioma, axillary lymph node dissection, A-V fistula, upper limb amputation) could theoretically result in an impaired immune response due to impaired vaccine absorption, although there are no data to support this. Consider an alternative injection site if possible. There is no evidence or theoretical rationale for avoiding injection through a tattoo or superficial birthmark.
Active immunizing agents should not be administered into the buttock (gluteal muscle). The gluteal muscle is an acceptable site for administration of Ig when large volumes are administered, and activation of the immune system is not required, but appropriate site selection of the gluteal muscle is necessary to avoid injury to the sciatic nerve.
For additional information about administration of parenteral vaccines to people with bleeding disorders refer to Immunization of Persons with Chronic Diseases in Part 3.
Intramuscular (IM) injections
Intramuscular injections of vaccine are administered into the anterolateral thigh muscle (vastus lateralis) in newborns, preterm infants and infants less than 12 months of age. The anterolateral thigh or the deltoid muscle can be used for toddlers and older children. The deltoid is usually often selected as the injection site in these age groups as temporary muscle pain post-vaccination in the anterolateral thigh muscle may affect ambulation. The deltoid muscle of the arm is the preferred injection site in adolescents and adults (unless the muscle mass is not adequate, in which case the anterolateral thigh can be used). Clinical judgment should be used when selecting needle length for IM injections as consideration should be given to vaccine recipient's weight, gender and age. IM injections should be administered at a 90o angle. The skin should be stretched flat (between thumb and forefinger) at the time of administration.
Large volumes of immune globulin for IM injection (greater than 2 mL for children or greater than 3 to 5 mL for adults, depending on muscle mass) should be divided and injected at 2 or more sites. Currently available human Ig preparations, with the exception of standard intravenous Ig, varicella Ig, CMV Ig, vaccinia Ig and botulism Ig must not be given IV because of the risk of rare anaphylactic reactions.
Subcutaneous (SC) injections
For infants younger than 12 months of age, the usual site for SC administration of vaccine is the subcutaneous tissue of the anterolateral thigh; if necessary, the upper triceps area of the arm may be used. SC injections for vaccine recipients 12 months of age and older are usually given into the subcutaneous tissue of the upper triceps area of the arm. SC injections should be administered at a 45o angle. Pinching of the skin may be necessary to ensure injection into the subcutaneous tissue.
Intradermal (ID) injections
ID vaccine administration technique is product-specific and should be applied according to the vaccine's product monograph or product leaflet.
The inner forearm is the preferred site for ID injections. The skin should be pulled taut with the non-dominant hand at the time of administration to ensure easy penetration of the needle. ID injections should be administered at a 5° to 15° angle. The needle should be inserted slowly into the dermis until the entire bevel is under the skin without aspirating. The injection should produce a noticeable pale elevation of the skin known as a wheal. A wheal is an area of the skin that is raised like a blister or bubble. The presence of a wheal 6 mm to 10 mm in diameter indicates that the medicine has been administered into the dermis properly. If a wheal does not form, remove the needle and repeat the procedure in preferably a separate anatomic injection site (different limb) or in the same limb but separated by at least 2.5 cm (1 inch).
Multiple parenteral injections
All opportunities to immunize should be used. Giving multiple vaccines at the same clinic visit is encouraged as it helps to ensure that individuals are up-to-date with the vaccines required for their age and risk factors. Practice considerations for multiple injections include the following:
- When drawing up multiple vaccines, it is best to do so for an individual client only.
- Syringes should be labelled to identify which vaccine each syringe contains.
- The site of administration of each vaccine should be recorded, so that if an injection site reaction occurs, the associated vaccine can be identified.
- If multiple parenteral injections are required, whenever possible, separate anatomic injection sites (different limbs) should be used. If multiple injections in the same limb are required, the injection sites should be separated by at least 2.5 cm (1 inch). In individuals where there is insufficient deltoid muscle mass, the anterolateral thigh muscle can be used.
- Vaccines that are known to cause the most injection site pain (e.g., Prevnar®13; M-M-R®II, human papillomavirus vaccines [HPV]) should be administered after other vaccines.
- If a vaccine and an Ig preparation are administered concurrently (e.g., tetanus toxoid-containing vaccine and tetanus Ig), separate anatomic injection sites (different limbs) should be used for each injection.
Oral vaccines should be administered as directed in the product leaflet. In general, oral vaccines should be given prior to injectable vaccines. If an incomplete dose of an oral vaccine is administered for any reason (e.g., infant spits or regurgitates the vaccine), a replacement dose should not be administered. Rotavirus vaccine can be given by NG or NJ tube. It should be administered and the tube rinsed according to local protocols for administration of oral medications into NG or NJ tubes.
Live attenuated influenza vaccine (LAIV) is the only vaccine in Canada administered by the intranasal route. LAIV should be administered by a health care provider following the instructions in the product leaflet. If the vaccine recipient sneezes immediately after administration, there is no need to repeat the dose. If significant nasal congestion is present that might impede delivery of LAIV to the nasopharyngeal mucosa, an inactivated vaccine can be administered or LAIV can be deferred until resolution of the illness.
Refer to Contents of Immunizing Agents Authorized for Use in Canada in Part 1 for information about the recommended route of administration for specific vaccines and passive immunizing agents authorized for use in Canada.
Techniques to decrease immunization injection pain
Vaccine injections can be a source of distress for individuals of any age, as well as for the immunization provider. If not addressed, the pain and anxiety associated with immunization can increase fear leading to avoidance of future medical procedures and lack of adherence to immunization schedules. It is estimated that up to 25% of adults have needle fears and 10% have needle phobias, defined as a marked and persistent fear that is excessive or unreasonable, cued by the presence of needles or anticipation of vaccination. The majority of people with needle fears develop them in childhood. Efforts to minimize pain can help to promote satisfaction and trust in health care providers and potentially prevent the development of needle fears.
Evidence exists for effective pharmacologic, physical, and psychological interventions to manage pain during immunization. Combining strategies has been shown to improve pain relief.
Refer to Table 4 for a listing of pain management strategies for children by age groups.
|Pain management strategies
|Infants and young children (3 years of age and under)Table 4 - Footnote 2
|Children (3 to 12 years)Table 4 - Footnote 2
|Adolescents (12 to 17 years)Table 4 - Footnote 2
|Adults (≥ 18 years)
Mothers should be encouraged to breastfeed their infants before, during, and after the immunization. Breastfeeding during immunization reduces pain and distress through:
- presence of a comforting person
- diversion of attention (sucking and distraction)
- physical sensation of skin-to-skin contact with mother
- sweet taste of breast milk and other substances in the milk (e.g., tryptophan [a precursor of melatonin] which has been reported to increase the concentration of ß-endorphins, thereby producing analgesia and relaxation).
Children up to 24 months of age should be breastfed before vaccine administration if a mother chooses not to breastfeed during vaccine injection. Alternatives to breastfeeding such as bottle feeding with expressed breast milk or formula should be considered if a mother chooses not to breastfeed or the infant is normally fed by other methods.
Children up to 24 months of age, who are not breastfed during immunization, may be given a sweet-tasting solution such as sucrose or glucose solution 1 to 2 minutes before vaccine injection. Administration of a sweet-tasting solution in addition to breastfeeding before vaccine injections is not recommended. The analgesic effect of a sweet-tasting solution has been demonstrated to last for up to 10 minutes following administration, and can mitigate vaccine injection pain. A sweet-tasting solution is recommended for the management of painful medical interventions only; it should not be used at home as a comfort measure for infants.
Proper positioning can reduce pain and anxiety. Skin-to-skin contact during vaccine injections is recommended for infants up to 1 month of age who are not breastfed during vaccine injection. For children up to 3 years of age, holding is recommended during vaccine injections. If not used during vaccine injections, a combined holding intervention with patting or rocking after vaccine injections is recommended in children up to 3 years of age.
Sitting upright during vaccine injections is recommended for all individuals 3 years of age and older.
Topical local anesthetics
Topical local anesthetics act by inhibiting the generation and transmission of pain impulses across nerve endings located in the dermis. They decrease the pain as the needle penetrates the skin and reduce the underlying muscle spasm, particularly in case of sequential injections. Topical anesthetics are effective in reducing vaccine injection pain and should be applied before vaccine administration.
There is no evidence that the application of a topical local anesthetic poses a risk of decreased immune response to vaccines if the topical anesthetic is used as directed in the product leaflet and for the ages recommended by the manufacturer. Because serious adverse events have been reported following excessive application, children should be observed during and after use of topical anesthetics, as they may be at greater risk than adults for serious adverse events. For additional information refer to Health Canada's advisory Safety information regarding topical anesthetics and serious adverse events - For Health Professionals.
Administration of oral analgesics (such as acetaminophen or ibuprofen) to children to reduce pain prior to or at the time of vaccine injection is not recommended, as there is no evidence of a benefit from this intervention.
Injection without aspiration
Aspiration prior to injection of vaccine is not recommended, as there are no large blood vessels at the recommended immunization sites and not aspirating before injection has been demonstrated to reduce pain.
Order of vaccine administration
When administering multiple vaccine injections sequentially, the vaccine that causes the most injection site pain should be injected last.
Techniques to decrease anxiety and fainting
The likelihood of fainting is reduced by measures that lower stress in those awaiting immunization, such as short waiting times, comfortable room temperature, preparation of vaccines out of view of recipients, and privacy during the procedure. To reduce injuries due to fainting, people should be immunized while seated, or if considered at high-risk, while lying down.
Foster a safe environment by educating immunization personnel and vaccinees on avoiding unsafe activities, such as stair climbing or driving immediately after immunization. For example, school immunization programs may wish to institute a pairing policy (two students remain together) so vaccinees are not alone for the first 10 to 15 minutes after leaving the immediate clinic location, in case they faint and fall or begin to experience symptoms of anaphylaxis.
Post-vaccination counselling and observation
Vaccine recipients should be counselled about the reporting and management of common adverse events following immunization. The use of an adhesive bandage to cover an injection site is optional but may be desired to prevent a tiny amount of blood from staining clothing. For treatment of minor adverse reactions such as fever or injection site discomfort that might occur following vaccination, oral analgesics and antipyretics (such as acetaminophen or ibuprofen) can be used. There is no evidence that antipyretics prevent febrile seizures.
Vaccine recipients should be kept under observation for at least 15 minutes after immunization; 30 minutes is a preferred interval when there is a specific concern about a possible vaccine reaction. In low-risk situations, observation can include having vaccine recipients remain within a short distance of the vaccine provider (e.g., within the school when immunization is carried out in that setting) and in the company of another person, able to return immediately for assessment if they feel unwell. Every vaccine provider should be familiar with the signs and symptoms of anaphylaxis and be prepared to act quickly. Refer to Anaphylaxis and Other Acute Reactions Following Vaccination in Part 2. For information about fainting, anxiety or breath-holding, refer to Anaphylaxis and Other Acute Reactions Following Vaccination in Part 2.
Vaccine recipients or their caregivers should be advised to notify their vaccine provider or other healthcare provider about any concerns that arise following immunization. The provider can then assess these concerns and, if appropriate, complete an adverse event following immunization (AEFI) report. For information about AEFI reporting, refer to Adverse events following immunization in Part 2.
Infection prevention and control
Vaccine providers should incorporate routine infection control practices into all immunization procedures as follows:
- Hand hygiene should be performed before vaccine preparation, between vaccine recipients, and whenever the hands are soiled. Alcohol-based hand sanitizers are an alternative to hand washing with soap and water when hands are not visibly soiled. Hand hygiene should be performed after removing gloves.
- Glove use during immunization is not routinely recommended unless the skin on the vaccine provider's hands is not intact or when administering Bacille Calmette-Guérin (BCG) or smallpox vaccine. If gloves are worn, they should be changed between vaccine recipients.
- Prior to withdrawal of vaccine into the syringe, the vaccine vial should be uncapped, the stopper wiped with a suitable disinfectant (e.g., isopropyl alcohol) and the stopper allowed to dry.
- Before injection, the skin should be cleansed with a suitable antiseptic such as an alcohol swab and allowed to dry.
- A separate sterile needle and syringe should be used for each injection.
- Policies and procedures should be developed and implemented regarding accidental exposure to blood or body fluids, including needle stick injuries, and vaccine providers should be educated about these policies and procedures. Refer to Immunization of Workers in Part 3 for more information about vaccines recommended for health care workers.
In addition to the recommendations above, the following practices should be observed:
- The needle should not be changed between withdrawing vaccine from the vial and administering the vaccine, unless the needle is contaminated or damaged.
- Needles should not be recapped after use.
- Used syringes and needles should be immediately and carefully disposed of in a container designed for this purpose; used syringes and needles should never be placed on the work surface.
- Empty or expired vaccine vials should be disposed of according to local waste management legislation or guidelines.
Additional information on infection prevention and control guidelines is available in Routine Practices and Additional Precautions for Preventing the Transmission of Infection in Healthcare Settings.
- Australian Government, Department of Health. The Australian Immunisation Handbook. 10th edition. Accessed February 2017 at: http://www.health.gov.au/internet/immunise/publishing.nsf/Content/Handbook10-home
- Batenburg J, Gombar R, Nagberi-Asseez, A et al. Recommendations for the Prophylactic Use of Analgesics and Antipyretics: Review of the effect of over the counter analgesics and antipyretics on adverse events following immunization and vaccine efficacy. Region of Peel. 2011. Accessed June 2015 at: http://www.peelregion.ca/health/resources/pdf/Analgesics_and_Antipyretics.pdf
- Beirne PV, Hennessy S, Cadogan SL, Sheily F, Fitzgerald T, MacLeod F. Needle size for vaccination procedures in children and adolescents. Cochrane Database of Systematic Reviews 2015, Issue 6.
- Centers for Disease Control and Prevention. Vaccine Administration. In: Pink Book. Accessed January 2017 at: https://www.cdc.gov/vaccines/pubs/pinkbook/vac-admin.html
- Centers for Disease Control and Prevention. Vaccine Recommendations and Guidelines of the ACIP. Accessed April 2017 at: https://www.cdc.gov/vaccines/hcp/acip-recs/general-recs/administration.html
- Cook, I.F. (2016) Sepsis, parenteral vaccination and skin disinfection. Human Vaccines & Immunotherapeutics. 2016;12(10): 2546-2559.
- Government of the United Kingdom, Department of Health. Green Book: Immunisation against infectious disease. Accessed February 2017 at: https://www.gov.uk/government/collections/immunisation-against-infectious-disease-the-green-book
- Immunization Action Coalition. Administering Vaccines: Dose, Route, Site, and Needle Size. Accessed February 2017 at: http://www.immunize.org/catg.d/p3085.pdf
- Jackson LA, Peterson D, Nelson JC et al. Vaccination Site and Risk of Local Reactions in Children 1 Through 6 Years of Age. Pediatrics 2012;131(2):283-89.
- Kimberlin DW, Brady MT, Jackson MA, Long SS (editors). Red Book: 2015 Report of the Committee on Infectious Diseases. 30th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2015.
- Kroger AT, Duchin J, Vázquez M. General Best Practice Guidelines for Immunization. Best Practices Guidance of the Advisory Committee on Immunization Practices (ACIP). Accessed May 2017 at: https://www.cdc.gov/vaccines/hcp/acip-recs/general-recs/index.html
- Public Health Agency of Canada. Immunization Competencies for Health Professionals. 2008. Accessed February 2017 at: /content/canadasite/en/public-health/services/publications/healthy-living/immunization-competencies-health-professionals.html
- Public Health Agency of Canada. Routine Practices and Additional Precautions for Preventing the Transmission of Infection in Healthcare Settings. 2012. Accessed January 2017 at: /content/canadasite/en/public-health/services/infectious-diseases/nosocomial-occupational-infections/routine-practices-additional-precautions-preventing-transmission-infection-healthcare-settings.html
- Taddio A, McMurtry CM, Shah V et al. (HELPinKIDS&Adults Team) Reducing pain during vaccine injections: clinical practice guideline. CMAJ 2015; 187(13): 975-982.
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