#### Volume 12, Number 10—October 2006

*Research*

# Health Benefits, Risks, and Cost-Effectiveness of Influenza Vaccination of Children

## Table 1

Variable | Most likely estimate | Range for sensitivity analysis | ||
---|---|---|---|---|

Influenza illness attack rate (annual) | ||||

6-23 mo | 0.157 | 0.02–0.35 | ||

2 y | 0.155 | 0.02–0.35 | ||

3–4 y | 0.155 | 0.01–0.35 | ||

5–11 y | 0.08 | 0.01–0.18 | ||

12–17 y | 0.06 | 0.01–0.14 | ||

Probability of outpatient visit for child with influenza illness‡ | ||||

6–23 mo | 0.5 | 0.17–0.83 | ||

2 y | 0.47 | 0.15–0.81 | ||

3–4 y | 0.43 | 0.12–0.78 | ||

5–11 y | 0.28 | 0.11–0.5 | ||

12–17 y | 0.24 | 0.06–0.5 | ||

Probability of otitis media for child with medically attended influenza illness | ||||

6–23 months | 0.63 | 0.33–0.8 | ||

2 y | 0.58 | 0.27–0.8 | ||

3–4 y | 0.39 | 0.17–0.6 | ||

5–11 y | 0.23 | 0.05–0.5 | ||

12–17 y | 0.15 | 0.01–0.4 | ||

Probability of nonhospitalized pneumonia or other outpatient complication for child with medically attended influenza illness§ | ||||

6–23 mo | 0.2 | 0.04–0.5 | ||

2 y | 0.15 | 0.02–0.4 | ||

3–4 y | 0.15 | 0.02–0.4 | ||

5–11 y | 0.11 | 0.02–0.3 | ||

12–17 y | 0.08 | 0.01–0.2 | ||

Hospitalizations for pneumonia or other respiratory conditions due to influenza/10,000 children not at high risk¶ | ||||

6-23 mo | 28.3 | 1.9–80.0 | ||

2 y | 17.1 | 0–56.8 | ||

3–4 y | 8.0 | 0–35.4 | ||

5–11 y | 3.1 | 0–16.0 | ||

12–17 y | 3.1 | 0–14.9 | ||

Probability of long-term sequelae following influenza-related hospitalization‡ | 0.01 | 0.001–0.03 | ||

Probability of death during influenza-related hospitalization | 0.0009 | 0–0.002 | ||

Vaccine effectiveness in preventing influenza illness# | ||||

IIV | 0.69 | 0.4–0.9 | ||

LAIV | 0.838 | 0.6–0.96 | ||

Probability of medically attended vaccination-related adverse events | ||||

Injection site reaction | ||||

6-23 mo | 0.008 | 0.002–0.017 | ||

2 y | 0.003 | 0.001–0.006 | ||

3–4 y | 0.002 | 0.0004–0.003 | ||

5–11 y | 0.001 | 0.0002–0.002 | ||

12–17 y | 0.0003 | 0.0001–0.001 | ||

Systemic reaction (fever)** | ||||

6–23 mo | 0.013 | 0.001–0.025 | ||

2 y | 0.011 | 0.0008–0.020 | ||

3–4 y | 0.009 | 0.0007–0.016 | ||

5–11 y | 0.004 | 0.0003–0.008 | ||

12–17 y | 0.003 | 0.0002–0.005 | ||

Anaphylaxis | 0.00000025 | 0–0.000001 | ||

Guillain-Barré syndrome | 0.000001 | 0–0.00001
*IIV, inactivated influenza vaccine; LAIV, live, attenuated influenza vaccine. |

*IIV, inactivated influenza vaccine; LAIV, live, attenuated influenza vaccine.

†Refer to Table A1 for list of references used to derive model inputs.

‡Estimates for children not at high risk are shown. Probabilities are estimated to be twice as high for children at high risk for influenza-related complications.

§Estimates for healthy children shown. Probabilities are estimated to be <5 times as high for children at high risk for influenza-related complications. Most likely estimates for children at high risk are 1.6 times as high as for healthy children.

¶Children at high-risk are estimated to be hospitalized at 3–6 times the rate of children not at high risk.

#Assumes vaccine is poorly matched with circulating virus 1 in 10 years (i.e., vaccine effectiveness is assumed to be 0 years with a poor match).

**Definitions and follow-up for incidence of fever following vaccination vary by study. Rates are 2× higher for children at high risk.