| Endemicity* | % of carriers in population | % of infected population | Age of infection | Strategy for vaccination |
|---|---|---|---|---|
| *Endemic: prevalent continuously to some degree in a community or region. | ||||
| †In children, infection is rarely acute with 25–90% becoming chronic carriers. | ||||
| ‡In adults, infection is often acute with 5–10 % becoming chronic carriers. | ||||
| §High risk groups such as sexual/household contacts of infected person, healthcare workers, injection drug users, those receiving non-sterile acupuncture or tattooing, homosexual and active heterosexual men. | ||||
| ¶30% of those with acute infection do not have identifiable risk factors. | ||||
| High | >8 (8–20) | 70–90 < the age of 40 | Mostly perinatal and childhood period† | Universal infant and high risk group |
| Intermediate | 2–8 | 20–70 | Both childhood and adult‡ | Universal infant and high risk group |
| Low | <2 | <20 | Mostly high risk adolescents and adults§,¶ | Universal infant or adolescent and/or high risk group |