Adverse Events Following Immunization (AEFI) Quarter 4 Report for 2016 (October 1 – December 31)

Safety Assessment Summary for Quarter 4:

  • No vaccine safety signals were identified in Quarter 4 of 2016.
  • This report presents 902 AEFI reports routinely received from federal, provincial and territorial jurisdictions during Q4.


Vaccines are closely monitored in Canada at all phases of the vaccine product 'life cycle' from discovery through market authorization (pre-market) and beyond, as people begin using them (post-market). Many stakeholders are involved in vaccine safety surveillance including the federal government, provincial, territorial and local public health authorities, health care providers, vaccine industry and the public. Provincial and territorial vaccination programs monitor AEFIs and report them to the Public Health Agency of Canada (the Agency). The Agency conducts post-market safety surveillance through the Canadian Adverse Events Following Immunization Surveillance System (CAEFISS). Vaccine safety concerns are monitored and addressed through the Vaccine Vigilance Working Group (VVWG).

An Adverse Event Following Immunization (AEFI) is defined as any untoward medical occurrence which follows immunization and which does not necessarily have a causal relationship with the usage of the vaccine. The adverse event may be any unfavourable or unintended sign, abnormal laboratory finding, symptom or disease. Serious AEFIs are those which are life-threatening, result in hospitalization or a prolongation of hospitalization, result in persistent or significant disability, or where the outcome is a birth defect or death, as defined by the World Health Organization (WHO). AEFIs not meeting the definition of a serious event are classified as non-serious.

WHO defines a vaccine safety signal as information (from one or multiple sources) that indicates a new and potentially causal association, or a new aspect of a known association, between a vaccine and an event previously unknown or incompletely documented that could affect health. Epidemiological studies are usually needed to assess the causal relationship between the vaccine and the signal. The primary purpose of vaccine post market surveillance is to detect safety concerns. These concerns include a possible increase in the severity or frequency of expected AEFIs, or occurrence of one or more unexpected events (i.e., an event that is not consistent with Canadian product information or labeling). This allows vaccination providers and public health vaccination program providers to take public health action at the level of the:

  • individual (such as further investigations to confirm a diagnosis and determine possible causes, consultation to rule out allergy to one or more vaccine components, or evaluate whether or not to give subsequent doses of a vaccine), and/or
  • vaccination program (such as investigation of a cluster of adverse events, review of procedures to ensure that vaccine storage requirements have been strictly followed, or consideration of a change in policy to adopt a less reactogenic vaccine).

The Agency also shares AEFI data with Health Canada's Health Products and Foods Branch, the national regulatory authority for vaccines in Canada. This enables formal action related to vaccines marketed in Canada to take place if needed. These actions may include issuing communications to vaccination providers or the public regarding the safety concern or requiring additional information or investigation by the vaccine distributor, or changes to the product labeling.

Vaccine safety surveillance reports summarizing CAEFISS data are released by the Agency on a routine basis. The Quarterly Reports summarize all AEFI reports received by the Agency from January to March (Quarter 1), April to June (Quarter 2), July to September (Quarter 3) and October to December (Quarter 4), regardless of the date the vaccine was given.

In this report, the 2016 quarterly data as well as the four year averages are shown. However, because these data reflect the date the reports were received and not the date the vaccine was given, the ability to compare and interpret patterns is limited. The report does provide a data snapshot that highlights serious and non-serious AEFI reports received for descriptive purposes.

Notes on interpretation: AEFI reports submitted to the Public Health Agency of Canada represent a suspicion, opinion, or observation by the reporter as opposed to an assertion or proof that the vaccine may have caused the event. Additional limitations to AEFI report data include potential underreporting, lack of certainty regarding the diagnostic validity of a reported event, missing information regarding other potential causes and other reporting biases. These biases are mitigated by the Agency through use of a national AEFI reporting form with a guide to its use, standardized medical coding using the Medical Dictionary for Regulatory Activities (MedDRA), follow-up with the jurisdictions for completeness of information, high reporting rates and inclusion of an active pediatric surveillance component in CAEFISS.

Results Highlighted for Quarter 4 of 2016

Data presented in this Quarterly Report (Q4) include AEFI reports routinely received from October 1, 2016 to December 31, 2016 and comparisons are made to the average number of reports received in the same quarter over the previous four calendar years (2012-2015). The data analysed were extracted from the CAEFISS database on June 30, 2017 by the Agency. It is important to note that technical issues have affected data submission from three jurisdictions and must be considered when interpreting these results. Technical issues prevented one jurisdiction from providing some data from 2012-2015; these issues were resolved in 2016. Also, one jurisdiction provided a batch of serious reports in Q4 2016 with dates of vaccination dating back to 2013. Together, these resulted in an apparent increase in the number of AEFI reports received in Q4 2016 when compared to previous quarters. Finally, as mentioned in previous reports, one jurisdiction has not been able to provide data to CAEFISS since 2013 and is excluded from this report.

All reports are processed and coded using MedDRA, a standardized medical terminology that supports data entry, retrieval, evaluation and presentation of clinical information and further coded with a main reason for reporting through a detailed review of individual case safety reports. Therefore, if more than one event is described, the one that is determined to have led to reporting is coded as the primary AEFI. In addition, all reports describing a serious event were reviewed and unless highlighted in this report, found either to be expected (based on known vaccine-related adverse reactions), to have alternate explanations not related to vaccination, or are currently being monitored or investigated further.

Number of AEFI and Serious AEFI Reports

A total of 902 AEFI reports were submitted to the Agency in the fourth quarter of 2016; during Q4 of 2012, 2013, 2014 and 2015, the Agency received an average of 742 (range: 609-1022) [Figure 1].

A total of 103 AEFI reports received by the Agency in Q4 of 2016 were classified as serious(13% of all AEFI reports). During Q4 of 2012, 2013, 2014 and 2015, the Agency received an average of 54 (range: 35-63) serious AEFI reports (6% to 9% of all AEFI reports). As noted above, the backlog of AEFI reports received from two jurisdictions led to an apparent increase in the total number of AEFI reports received during this quarter.

Figure 1: Total AEFI reports received, by calendar quarter (serious and non-serious), Q1-Q4, 2016 compared to the average of the previous four years
Figure 1. Text version below.
Figure 1 - Text description
Total Number of AEFI Reports Received Each Quarter
Quarter Serious Cases Non-Serious Cases
Q1 (Jan - Mar) 2016 51 586
Q1 Average 2012 - 2015 62 828
Q2 (Apr - Jun) 2016 41 578
Q2 Average 2012 - 2015 46 625
Q3 (July - Sep) 2016 40 487
Q3 Average 2012 - 2015 43 460
Q4 (Oct - Dec) 2016 103 799
Q4 Average 2012 - 2015 54 687

Frequency of Serious and Non-serious AEFI Reports by Age Group

Table 1 shows the number of serious and non-serious AEFI reports by age group in Q4 of 2016 and comparison with the 2012-2015 Q4 average. As noted above, the backlog of AEFI reports received from two jurisdictions led to an apparent increase in the total number of AEFI reports received during this quarter; however, the proportion of AEFI reports by age group was similar to previous years.

Table 1: Total AEFI reports received (proportion of total reports), by age group (serious and non-serious), Q4 2016 and Q4 2012-15 average
Age Group Serious reports Non-serious reports
2016 Average 2012-2015 2016 Average 2012-2015
0 to <1 year 37 (35.9%) 16 (31.2%) 89 (11.1%) 76 (11.1%)
1 to <2 years 29 (28.2%) 14 (25.8%) 100 (12.5%) 77 (11.2%)
2 to <7 years 12 (11.7%) 7 (12.9%) 76 (9.5%) 67 (9.7%)
7 to <18 years 8 (7.8%) 4 (7.4%) 137 (17.1%) 106 (15.4%)
18 to <65 years 14 (13.6%) 9 (16.6%) 297 (37.2%) 267 (38.9%)
65 years and over 2 (1.9%) 4 (7.4%) 95 (11.9%) 90 (13.1%)
Unknown 1 (1.0%) 1 (1.8%) 5 (0.6%) 6 (0.9%)
Total 103 54 799 687

AEFIs by Major Classification

Figure 2 presents the main types of AEFIs (both serious and non-serious) reported during Q4 of 2016. Most of the AEFIs reported were vaccination site reactions, followed by allergic or allergic-like event.

Figure 2: Primary reason for AEFI reporting, Q4, 2016 (serious and non-serious), N=902
Figure 2. Text version below.
Figure 2 - Text description
Main Reasons for Reporting an Adverse event following immunization
Main Reasons for Reporting Percentage
Reaction at or near the vaccination site 36%
Allergic or allergic-like events 24%
Other eventsfigure 2 table note 1 13%
Rash 10%
Systemic event 8%
Neurological event 8%
Vaccination anxiety 1%
Figure 2 table notes
Figure 2 table note 1

Other events include: gastro-intestinal reaction, para/anesthesia, thrombocytopenia, hypotonic-hyporesponsive episode, intussusception, arthritis, arthralgia, parotitis, SUDS, and undefined - other

Return to figure 2 table note 1 referrer

The main types of AEFI reported by level of seriousness for Q4 of 2016 compared to the 2012-2015 Q4 average are shown in Table 2. In Q4 of 2016 as well as in the past four years, reactions at or near the vaccination site, allergic or allergic-like events, and rash were the main AEFIs reported for non-serious cases. Neurologic events (which are most often seizures triggered by fever) and systemic events (i.e., events involving many body systems often accompanied by fever) were the most frequent AEFIs reported for the serious cases; the number of serious cases increased for both reported AEFI in Q4 2016 compared to the 2012-2015 Q4 average. Also, the number of serious allergic or allergic-like reactions increased in 2016 due to a change in the classification of serious events in mid-2015, as now all anaphylaxis cases are coded as life-threatening and therefore classified as serious, even if they did not result in hospitalization, prolongation of hospitalization, or death.

Table 2: Total AEFI reports received (proportion of total reports), by primary AEFI reported (serious and non-serious), Q4, 2016, compared to 2012-15 average
Primary AEFI reported Serious reports Non-serious reports
2016 Average 2012-15 2016 Average 2012-15
Reaction at or near the vaccination site 6 (5.8%) 5 (9.3%) 323 (40.4%) 273 (39.7%)
Allergic or allergic-like event 13 (12.6%) 3 (5.6%) 200 (25.0%) 115 (16.7%)
Rash 0 (0%) 1 (1.9%) 91 (11.4%) 124 (18.0%)
Systemic event 20 (19.4%) 14 (25.9%) 50 (6.3%) 65 (9.5%)
Neurologic event 42 (40.8%) 16 (29.6%) 27 (3.4%) 18 (2.6%)
Vaccination anxiety 0 (0%) 0 (0%) 10 (1.3%) 10 (1.5%)
Vaccination error 0 (0%) 0 (0%) 0 (0%) 8 (1.2%)
Other eventstable 2 note 1 22 (21.4%) 15 (27.8%) 98 (12.3%) 75 (10.9%)
Total 103 54 799 687
Table 2 Note 1

Other events include: gastro-intestinal reaction, para/anesthesia, thrombocytopenia, hypotonic-hyporesponsive episode, intussusception, arthritis, arthralgia, parotitis, SUDS, and undefined - other

Return to table 2 note 1 referrer

Vaccines Administered in AEFI Reports

Table 3 lists the most commonly administered vaccines among AEFI reports received for Quarter 4 of 2016. Influenza vaccines had the most AEFI reports consistent with the high volume of vaccines administered each year. As seen in previous years, the highest proportion of serious reports were following pneumococcal, meningococcal, DTaP infant series, and measles, mumps, rubella, varicella (MMRV and MMR + V) vaccines.

Table 3: Total AEFI reports received (proportion of total reports), by vaccine administered (serious and non-serious), Q4, 2016, compared to 2012-15 averagetable 3 note 1
Vaccines administered Serious reports Non-serious reports
2016 Average 2012-15 2016 Average 2012-15
1. DTaP booster 2 (0.8%) 1 (0.9%) 12 (0.9%) 14 (1.4%)
2. DTaP infant series 37 (15.6%) 19 (17.6%) 120 (9.2%) 94 (9.1%)
3. Hepatitis B 8 (3.4%) 3 (2.8%) 59 (4.5%) 44 (4.3%)
4. Human papillomavirus (HPV) 2 (0.8%) 2 (1.9%) 57 (4.4%) 37 (3.6%)
5. Influenza 27 (11.4%) 16 (14.8%) 300 (22.9%) 267 (26.0%)
6. Measles, mumps, rubella, varicella (MMRV and MMR + V) 37 (15.6%) 14 (13.0%) 173 (13.2%) 119 (11.6%)
7. Meningococcal 42 (17.7%) 15 (13.9%) 119 (9.1%) 91 (8.9%)
8. Other vaccines 1 (0.4%) 1 (0.9%) 11 (0.8%) 13 (1.3%)
9. Pneumococcal 55 (23.2%) 25 (23.1%) 219 (16.7%) 160 (15.6%)
10. Rotavirus 19 (8.0%) 9 (8.3%) 50 (3.8%) 34 (3.3%)
11. Tdap booster 2 (0.8%) 2 (1.9%) 126 (9.6%) 88 (8.6%)
12. Travel vaccines 5 (2.1%) 2 (1.9%) 38 (2.9%) 46 (4.5%)
13. Zoster virus 0 (0%) 0 (0%) 26 (2.0%) 24 (2.3%)
Total 237 108 1310 1028
Table 3 Note 1

Totals add up to more than the total number of AEFI reports as one AEFI report may involve more than one vaccine. Including

  1. DTaP-IPV, DTaP;
  2. DTaP-IPV-Hib, DTaP-HB-IPV-Hib, DTaP-Hib, DTaP-HB-IPV;
  3. HB, HB-H, HB-dial, HBTmf;
  4. HPV, HPV-2, HPV-4, HPV-9;
  5. Inf, Inf-NOS, H1N1-09;
  6. MMR, MMRV, Var;
  7. Men-C, Men-C-ACYW-135, Men-C-C, Men-B;
  8. Rab, Td;
  9. Pneu-C, Pneu-C-10, Pneu-C-13, Pneu-C-7, Pneu-P, Pneu-P-23;
  10. Rot-1, Rot-5, Rota;
  11. Tdap, Tdap-IPV, Td-IPV;
  12. Chol-Ecol-O, HA, HA-Typh-I, HAHB, Typh-I, YF;
  13. Zos.

DTaP-HB-IPV-Hib - Combined Diphtheria and Tetanus Toxoids, Acellular Pertussis, Hepatitis B (recombinant), Inactivated Poliomyelitis and adsorbed conjugated Haemophilus influenzae type b.

DTaP-Hib - Diphtheria and Tetanus Toxoids, acellular Pertussis, Haemophilus influenzae type b.

DTaP-IPV - Component Pertussis vaccine and Diphtheria and Tetanus Toxoids adsorbed, combined with Inactivated Poliomyelitis vaccine.

DTaP-IPV-Hib - Diphtheria and Tetanus Toxoids and Acellular Pertussis Vaccine Adsorbed, Combined with Inactivated Poliomyelitis Vaccine and Haemophilus b Conjugate Vaccine.

Return to table 3 note 1 referrer


This Quarter 4 report for 2016 is based on reports of adverse events received at the Agency from federal/provincial/territorial public health authorities and active, pediatric hospital based surveillance. Detailed evaluation of the reports and reporting patterns in collaboration with provincial/territorial vaccine safety focal points of the VVWG and Health Canada have not identified any vaccine safety signals of concern. The tables and figures in this report provide a snapshot of the data provided to, and reviewed by, the PHAC.

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