Published online by Cambridge University Press: 07 December 2009
Human herpes viruses 6, 7 and 8 all are double-stranded DNA viruses and belong to the family Herpesviridae.
HHV6 (beta herpesvirus)
HHV7 (beta herpesvirus)
HHV8 (gamma herpesvirus)
Route of spread
HHV6: aerosol transmission and saliva from mothers to babies and breast milk.
HHV7: aerosol transmission and saliva from mothers to babies and breast milk.
HHV8: there is some evidence of sexual spread via semen and possibly vertically from mother to child. HHV8 has been transmitted to transplant recipients from donor organs.
HHV6 infection is ubiquitous and occurs worldwide. Infection often occurs after 4 months of age, as maternally acquired immunity wanes.
HHV7 infection is ubiquitous and occurs worldwide. Most children (95%) acquire the infection by 5 years of age.
HHV8 infection is more prevalent in Italy, Greece, Israel and Saudi Arabia than in northern Europe. These countries have a higher prevalence of Kaposi's sarcoma. In the UK, the HHV8 antibody prevalence is <5% in blood donors and 30–50% in HIV-positive men who have sex with men (MSM). Human herpes virus 8 antibody prevalence is 85% in patients with Kaposi's sarcoma.
Immunocompromised patients are at increased risk of more severe infection and clinical disease.