A CD4 cell count below 500 cells/mm3
and a detectable viral load are risk factors for herpes zoster (shingles) in
HIV-positive people, US investigators report in the online edition of the Journal of Acquired Immune Deficiency
Syndromes. Complicated herpes zoster was common and was associated with a
very low CD4 cell count.
Studies conducted soon after combination
antiretroviral therapy became available showed a high incidence of herpes
zoster in HIV-positive people. Incidence of the disease was 32 cases per 1000
person-years, far higher than the 3.5 cases per 1000 person-years observed in
the general population.
However, there have been considerable
improvements in HIV treatment and care over the past decade and investigators
at Johns Hopkins University in Baltimore wanted to see if these had had an impact on
incidence of herpes zoster. They also wanted to determine if there were any
risk factors for the disease.
They therefore designed a study involving
4353 people who received care at their centre between 2002 and 2009. Each
person who developed herpes zoster was matched with three control individuals who
During the period of the study, there were
321 cases of herpes zoster involving 262 people. Some 57% of these were
incidence (new) cases; the remaining cases involved a recurrence of disease. People
with a first case of herpes zoster were significantly less likely than those
experiencing a recurrence to be taking HIV therapy (p = 0.004).
The incidence of disease over the entire
study period was 9.3 cases per 1000 person-years, significantly lower than the
incidence observed between 1997 and 2001, but still higher than that seen in
the general population.
Most of the people (62%) with incident
herpes zoster were men, African American (75%) and heterosexual (52%). Their
median age was 39 years. The majority (63%) smoked, 46% reported drinking
alcohol and 27% used illegal drugs.
Median CD4 cell count at the time herpes
zoster was diagnosed was 278 cells/mm3, with median viral load being
Three-quarters of participants were taking
antiretroviral therapy at the time of their diagnosis, and 6% had initiated
treatment within the past three months.
Herpes zoster was treated with antivirals
in 94% of people. The most frequently used therapy was valaciclovir. A fifth
of participants required hospitalisation. These individuals had a median CD4 cell
count of 233 cells/mm3, 68% were taking anti-HIV drugs and 74% were
treated with intravenous aciclovir.
Starting HIV treatment within the previous
three months was a risk factor for incident herpes zoster (AOR = 4.02; 95% CI,
“The association between early immune
reconstitution after starting ART [antiretroviral therapy] and herpes zoster
has been previously observed in smaller studies,” observe the
investigators. “Clinicians should be aware of the higher risk of herpes zoster
shortly after ART is started.”
A detectable viral load was also a
significant risk factor (AOR = 1.49; 95% CI, 1.00-2.24).
Compared to people with a CD4 cell count
above 500 cells/mm3, those with a CD4 cell count below 350 cells/mm3
(AOR = 2.46; 95% CI, 1.42-4.23) or between 350 and 500 cells/mm3 (AOR = 2.02;
95% CI, 1.14-3.57) had an increased risk of incident disease.
Over a quarter of participants (28%) developed
complications. The most common complications were neuralgia (11%), bacterial
infections (6%) and ocular involvement (6%). A CD4 cell count below 50 cells/mm3
was initially identified a risk factor for complications (OR = 2.86; 95% CI,
1.01-8.09). However, this association disappeared when the investigators took viral load
“There are several modifiable risk factors
for incident herpes zoster, including having a detectable HIV-1 RNA level
[viral load] and a low CD4 cell count,” conclude the authors.
Age was not found to be a risk factor.
However, in the general population the risk of shingles increases with age. “As
the HIV-infected population continues to age on effective ART, we may see a
greater burden of herpes zoster,” the authors therefore suggest.