Table 2. Number and distribution of varicella vaccine AEFIs in Ontario, by adverse event category, 2010−2013.
| Adverse event category1 | Adverse event2 | All AEFI reports n (%)3 | Serious AEFIs n (%)4 | Reporting rate (per 100,000 doses distributed) | Serious reporting rate (per 100,000 doses distributed) |
|---|---|---|---|---|---|
| Allergic events | Total | 37 (23.0) | 2 (5.4) | 3.3 | 0.2 |
| • Allergic reaction—other | 2 (1.2) | 0 (0.0) | 0.2 | 0 | |
| • Allergic reaction—skin | 33 (20.5) | 1 (3.0) | 3.0 | 0.1 | |
| • Event managed as anaphylaxis | 2 (1.2) | 1 (50) | 0.2 | 0.1 | |
| Injection site reactions | Total | 76 (47.2) | 2 (2.6) | 6.9 | 0.2 |
| • Cellulitis | 18 (11.2) | 2 (11.1) | 1.6 | 0.2 | |
| • Infected abscess | 1 (0.6) | 0 (0.0) | 0.1 | 0 | |
| • Sterile abscess | 1 (0.6) | 0 (0.0) | 0.1 | 0 | |
| • Nodule | 10 (6.2) | 0 (0.0) | 0.9 | 0 | |
| • Pain/redness/swelling | 53 (32.9) | 0 (0.0) | 4.8 | 0 | |
| Neurologic events | Total | 6 (3.7) | 4 (66.7) | 0.5 | 0.4 |
| • Convulsions/seizures | 5 (3.1) | 3 (60.0) | 0.5 | 0.3 | |
| • Encephalopathy/encephalitis | 1 (0.6) | 1 (100.0) | 0.1 | 0.1 | |
| Other events of interest | Total | 14 (8.7) | 1 (7.1) | 1.3 | 0.1 |
| • Arthritis/arthralgia | 1 (0.6) | 0 (0.0) | 0.1 | 0 | |
| • Syncope with injury | 1 (0.6) | 0 (0.0) | 0.1 | 0 | |
| • Other severe/unusual events | 12 (7.5) | 1 (8.3) | 1.1 | 0.1 | |
| Systemic events | Total | 69 (42.9) | 5 (7.2) | 6.2 | 0.5 |
| • Fever ≥38°C | 18 (11.2) | 4 (22.2) | 1.6 | 0.4 | |
| • Persistent crying/screaming | 1 (0.6) | 0 (0.0) | 0.1 | 0 | |
| • Rash | 60 (37.3) | 1 (1.7) | 5.4 | 0.1 | |
| • Severe vomiting/diarrhea | 2 (1.2) | 1 (50.0) | 0.2 | 0.1 |
1Adverse event categories represent groupings of specific types of adverse events and are not mutually exclusive. For category totals, reports with more than one specific event within a category are counted only once. Thus category totals will not be the sum to the total of specific adverse events overall or within a category. 2Includes only those adverse events where the count was at least one. 3Each AEFI report may contain one or more specific adverse events which are not mutually exclusive. Percentages will not sum to 100%. The denominator of 162 is the total number of confirmed varicella AEFI reports between 2010 and 2013. The specific type of adverse event was missing for one report in 2011, and thus was excluded from the total confirmed AEFI reports in this specific analysis (n=161). 4Percent of reports that were serious within each event.