Human papillomavirus (HPV) infection
doubles the risk of HIV acquisition for women, results of a systematic review
and meta-analysis published in the online edition of AIDS suggest.
The infection also increased the risk of
HIV acquisition for heterosexual and gay men, but only two studies examining
the association in these populations could be identified.
Between a fifth and a third of all HIV
transmissions were attributed to prevalent HPV infection. A number of
descriptive studies have pointed to an association between prevalent HPV
infection and an increased risk of acquisition of HIV. An international team of
investigators therefore conducted a systematic literature review and
meta-analysis to determine the association between this common infection and HIV acquisition in three populations: heterosexual women; gay and
other men who have sex with men; and heterosexual men. They also wished to see
how many HIV transmissions could be attributed to the presence of HPV
Nested case-controlled and cohort studies
published in a peer-reviewed journal or presented to a major conference before
July 2011 were eligible for inclusion in the analysis.
Only eight studies met the investigators’
criteria: six in women and one each in gay and heterosexual men. A total of
12,750 patients were included in these studies. None of the studies had as its primary aim assessment
of the association between the presence of HPV and infection with HIV.
The investigators combined the results of
the six studies conducted with women. They did not consider it appropriate to add the two
studies conducted with men to this analysis.
The presence of HPV infection doubled the
risk of HIV acquisition for women (aHR = 2.06; 95% CI, 1.44-2.94). The risk was
similar for HPV genotypes associated with a high risk of cervical cell changes
and cancer (aHR = 1.99; 95% CI, 1.54-2.46) and low-risk strains of the virus
(aHR = 2.01; 95% CI, 1.27-3.20).
Vaccines that provide a high level of
protection against incident infection with the HPV strains most associated with
cervical cancer have recently been approved for use in the UK. The meta-analysis showed that infection
with the genotypes covered by the quadrivalent vaccine (Gardasil) doubled the risk of acquisition of HIV (aHR = 2.00; 95%
“Clarification of the findings presented in
this study through well-conducted research is needed in high HPV/HIV settings,
in order to assess whether HPV vaccination might have an effect on HIV
incidence,” comment the researchers.
For gay men, infection with two or more HPV
genotypes more than tripled the risk of HIV acquisition (aHR = 3.5; 95% CI,
1.2-10.6). For heterosexual men, the presence of any HPV in the glans/coronal
sulcus of the penis was associated with an increased risk (aHR = 1.8; 95% CI,
“Combining the studies in women revealed a
near doubling of risks when an HPV genotype was identified prior to HIV
acquisition, with similar associations seen in the two studies in men,” comment
Neither the cervical nor the anal cell
abnormalities that can be caused by HPV increased the risk of infection with
They calculated that between 21 and 37% of
all HIV infections could be attributed to the presence of HPV.
However, the authors had concerns about the
quality of all the studies included in their analysis. Two of the studies
involving women did not adjust for sexual behaviour, whereas others did not
record data on transactional sex. “It is particularly difficult to collect
sufficiently detailed, rigorous, sexual behaviour data and for this reason,
residual confounding may affect all studies,” emphasise the researchers.