Table 2.
Percentage of participants in each age group with adverse reactions within 3 days after the first or the second injection*
| 7·5 μg HA | 15 μg HA | Seasonal influenza vaccine | ||||
|---|---|---|---|---|---|---|
| Any grade** | Grade 3** | Any grade** | Grade 3** | Any grade** | Grade 3** | |
| 6–23 months | n = 68 | n = 62 | n = 37 | |||
| Injection‐site reactions, No.(%, 95% CI) | ||||||
| Swelling | 0 (0·0, 0·0–6·7) | 0 (0·0, 0·0–6·7) | 1 (1·6, 0·1–9·9) | 0 (0·0, 0·0–7·3) | 0 (0·0, 0·0–11·7) | 0 (0·0, 0·0–11·7) |
| Pain | 1 (1·5, 0·1–9·0) | 0 (0·0, 0·0–6·7) | 1 (1·6, 0·1–9·9) | 0 (0·0, 0·0–7·3) | 0 (0·0, 0·0–11·7) | 0 (0·0, 0·0–11·7) |
| Redness | 0 (0·0, 0·0–6·7) | 0 (0·0, 0·0–6·7) | 0 (0·0, 0·0–7·3) | 0 (0·0, 0·0–7·3) | 0 (0·0, 0·0–11·7) | 0 (0·0, 0·0–11·7) |
| Rash | 0 (0·0, 0·0–6·7) | 0 (0·0, 0·0–6·7) | 0 (0·0, 0·0–7·3) | 0 (0·0, 0·0–7·3) | 0 (0·0, 0·0–11·7) | 0 (0·0, 0·0–11·7) |
| Systemic reactions, No.(%, 95% CI) | ||||||
| Fever | 14 (20·6, 12·1–32·5) | 0 (0·0, 0·0–6·7) | 16 (25·8, 15·9–28·8) | 1 (1·6, 0·1–9·9) | 7 (18·9, 8·6–35·9) | 1 (2·7, 0·1–15·9) |
| Diarrhea | 7 (10·3, 4·6–20·7) | 0 (0·0, 0·0–6·7) | 6 (9·7, 4·0–20·6) | 0 (0·0, 0·0–7·3) | 5 (13·5, 5·1–29·7) | 0 (0·0, 0·0–11·7) |
| Allergy | 0 (0·0, 0·0–6·7) | 0 (0·0, 0·0–6·7) | 1 (1·6, 0·1–9·9) | 0 (0·0, 0·0–7·3) | 0 (0·0, 0·0–11·7) | 0 (0·0, 0·0–11·7) |
| Decreases in activity levels | 2 (2·9, 0·5–11·2) | 0 (0·0, 0·0–6·7) | 2 (3·2, 0·6–12·2) | 1 (1·6, 0·1–9·9) | 1 (2·7, 0·1–15·9) | 0 (0·0, 0·0–11·7) |
| Cough | 3 (4·4, 1·1–13·2) | 0 (0·0, 0·0–6·7) | 3 (4·8, 1·3–14·4) | 0 (0·0, 0·0–7·3) | 0 (0·0, 0·0–11·7) | 0 (0·0, 0·0–11·7) |
| Irritability | 5 (7·4, 2·7–17·1) | 0 (0·0, 0·0–6·7) | 3 (4·8, 1·3–14·4) | 0 (0·0, 0·0–7·3) | 1 (2·7, 0·1–15·9) | 0 (0·0, 0·0–11·7) |
| Nausea or vomiting | 1 (1·5, 0·1–9·0) | 0 (0·0, 0·0–6·7) | 4 (6·5, 2·1–16·5) | 0 (0·0, 0·0–7·3) | 3 (8·1, 2·1–23·1) | 1 (2·7, 0·1–15·9) |
| Headache | 0 (0·0, 0·0–6·7) | 0 (0·0, 0·0–6·7) | 0 (0·0, 0·0–7·3) | 0 (0·0, 0·0–7·3) | 0 (0·0, 0·0–11·7) | 0 (0·0, 0·0–11·7) |
| Loss of appetite | 2 (2·9, 0·5–11·2) | 0 (0·0, 0·0–6·7) | 2 (3·2, 0·6–12·2) | 1 (1·6, 0·1–9·9) | 0 (0·0, 0·0–11·7) | 0 (0·0, 0·0–11·7) |
| Other | 2 (2·9, 0·5–11·2) | 0 (0·0, 0·0–6·7) | 3 (4·8, 1·3–14·4) | 0 (0·0, 0·0–7·3) | 0 (0·0, 0·0–11·7) | 0 (0·0, 0·0–11·7) |
| 24–35 months | n = 56 | n = 61 | n = 26 | |||
| Injection‐site reactions, No.(%, 95% CI) | 0 (0·0, 0·0–16·1) | 0 (0·0, 0·0–16·1) | ||||
| Swelling | 0 (0·0, 0·0–8·0) | 0 (0·0, 0·0–8·0) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–16·1) | 0 (0·0, 0·0–16·1) |
| Pain | 0 (0·0, 0·0–8·0) | 0 (0·0, 0·0–8·0) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–16·1) | 0 (0·0, 0·0–16·1) |
| Redness | 0 (0·0, 0·0–8·0) | 0 (0·0, 0·0–8·0) | 1 (1·6, 0·1–10·0) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–16·1) | 0 (0·0, 0·0–16·1) |
| Rash | 0 (0·0, 0·0–8·0) | 0 (0·0, 0·0–8·0) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–7·4) | 1 (3·8, 0·2–21·7) | 0 (0·0, 0·0–16·1) |
| Systemic reactions, No.(%, 95% CI) | ||||||
| Fever | 9 (16·1, 8·1–28·9) | 0 (0·0, 0·0–8·0) | 8 (13·1, 6·2–24·8) | 1 (1·6, 0·1–10·0) | 6 (23·1, 9·8–44·4) | 0 (0·0, 0·0–16·1) |
| Diarrhea | 4 (7·1, 2·3–18·2) | 1 (1·8, 0·1–10·8) | 1 (1·6, 0·1–10·0) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–16·1) | 0 (0·0, 0·0–16·1) |
| Allergy | 1 (1·8, 0·1–10·8) | 0 (0·0, 0·0–8·0) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–7·4) | 1 (3·8, 0·2–21·7) | 0 (0·0, 0·0–16·1) |
| Decreases in activity levels | 0 (0·0, 0·0–8·0) | 0 (0·0, 0·0–8·0) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–7·4) | 1 (3·8, 0·2–21·7) | 0 (0·0, 0·0–16·1) |
| Cough | 2 (3·6, 0·6–13·4) | 0 (0·0, 0·0–8·0) | 1 (1·6, 0·1–10·0) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–16·1) | 0 (0·0, 0·0–16·1) |
| Irritability | 1 (1·8, 0·1–10·8) | 0 (0·0, 0·0–8·0) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–16·1) | 0 (0·0, 0·0–16·1) |
| Nausea or vomiting | 1 (1·8, 0·1–10·8) | 0 (0·0, 0·0–8·0) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–16·1) | 0 (0·0, 0·0–16·1) |
| Headache | 2 (3·6, 0·6–13·4) | 0 (0·0, 0·0–8·0) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–16·1) | 0 (0·0, 0·0–16·1) |
| Loss of appetite | 0 (0·0, 0·0–8·0) | 0 (0·0, 0·0–8·0) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–7·4) | 0 (0·0, 0·0–16·1) | 0 (0·0, 0·0–16·1) |
| Other | 1 (1·8, 0·1–10·8) | 0 (0·0, 0·0–8·0) | 3 (4·9, 1·3–14·6) | 0 (0·0, 0·0–7·4) | 1 (3·8, 0·2–21·7) | 0 (0·0, 0·0–16·1) |
CI, confidence interval; HA, hemagglutinin.
*Values are for participants who received at least one dose of vaccine with 1 post‐vaccination safety measure.
**Coded with three grades of severity for redness, swelling, and induration across both age cohorts: mild (<10 mm), moderate (≥10 mm to ≤30 mm), or severe (>30 mm). Pain was graded as mild (minor reaction on touch), moderate (cries or protests on touch), or severe (cries when limb is moved or spontaneously painful). Coding for mild, moderate, and severe was the same for all systemic reactions in both age cohorts: mild (transient or mild discomfort (< 48 hours); no medical intervention/therapy required), moderate (mild to moderate limitation in activity – some assistance may be needed; no or minimal medical intervention/therapy required), or severe (marked limitation in activity, some assistance usually required; medical intervention/therapy required, hospitalizations possible). For fever, the grades were mild (≥37·1 to ≤37·5°C), moderate (≥37·6 to ≤39·0°C), and severe (>39·0°C).