CDC’s 2006 recommendations for human immunodeficiency virus (HIV) testing state that
all persons aged 13–64 years should be screened for HIV at least once, and that persons
at higher risk for HIV infection, including sexually active gay, bisexual, and other
men who have sex with men (MSM), should be rescreened at least annually (
1
). Authors of reports published since 2006, including CDC (
2
), suggested that MSM, a group that is at highest risk for HIV infection, might benefit
from being screened more frequently than once each year. In 2013, the U.S. Preventive
Services Task Force (USPSTF) found insufficient evidence to specify an HIV rescreening
interval but recommended annual screening for MSM as a reasonable approach (
3
). However, some HIV providers have begun to offer more frequent screening, such as
once every 3 or 6 months, to some MSM. A CDC work group conducted a systematic literature
review and held four expert consultations to review programmatic experience to determine
whether there was sufficient evidence to change the 2006 CDC recommendation (i.e.,
at least annual HIV screening of MSM in clinical settings). The CDC work group concluded
that the evidence remains insufficient to recommend screening more frequently than
at least once each year. CDC continues to recommend that clinicians screen asymptomatic
sexually active MSM at least annually. Each clinician can consider the benefits of
offering more frequent screening (e.g., once every 3 or 6 months) to individual MSM
at increased risk for acquiring HIV infection, weighing their patients’ individual
risk factors, local HIV epidemiology, and local testing policies.
HIV testing is the critical first step in making HIV-infected persons aware of their
status, so that they can obtain treatment and prevent transmission of HIV. In 2014,
CDC estimated that 15% of all persons living with HIV in the United States had undiagnosed
infections (
4
). Early HIV care and adherence to antiretroviral therapy (ART) prolong life and decrease
the chances of HIV transmission (
5
). The increasing availability of antigen-antibody HIV tests means that a greater
number of infections can be detected in the highly infectious, acute stage of infection
(
6
). The potential benefits of early detection and treatment of HIV were the driving
force behind CDC’s initiative to assess the benefits and harms associated with more
frequent screening of MSM. This policy note describes the results of that initiative.
Systematic Review
A CDC work group of federal employees comprising a diverse group of epidemiologists,
clinicians, behavioral scientists, health policy experts, and health economists was
convened. To identify studies comparing annual versus more frequent screening among
MSM, the CDC work group conducted a systematic literature review, using methods adapted
from the Guide for Community Preventive Services (
7
,
8
), and convened four consultations with 24 external experts to obtain their individual
input on the programmatic and scientific evidence. During 2013–2014, and updated in
January 2015, the CDC work group conducted a systematic review of published studies
indexed in MEDLINE, EMBASE, PsycINFO, and CINAHL. The search was restricted to articles
that 1) were published during 2005–2014 (last search conducted in January 2015); 2)
described analyses conducted in the United States, Canada, Australia, New Zealand,
and Western Europe; and 3) contained the following search terms: HIV seropositivity,
HIV infection, AIDS serodiagnosis, sexually transmitted diseases/infections, men who
have sex with men (MSM), high risk, test, screen. Included articles provided information
on one of four outcomes of interest: 1) health benefits to individual MSM being screened
or to the community (e.g., averted secondary HIV infections); 2) harms to individual
MSM (stigma or out-of-pocket costs); 3) acceptability (MSM attitudes toward more frequent
screening); or 4) feasibility (barriers to or facilitators of state or local screening).
Included studies were restricted to those conducted in clinical settings. A manual
search of gray literature was also conducted.
The CDC work group reviewed 6,479 abstracts resulting from the automated search, 111
of which met the initial screening inclusion criteria and were reviewed in full. Three
members of the CDC work group, working in overlapping pairs, applied inclusion criteria
to these studies, rating each study for outcome (benefits, harms, acceptability, or
feasibility). They used a quantitative study assessment tool to note key findings.
Discrepancies were resolved by a third reviewer who was not a member of the original
pair (
7
,
8
).
Thirteen studies met the inclusion criteria and were evaluated on quality of evidence
(
9
). For each of the four study outcomes, CDC HIV testing experts then evaluated the
quality of evidence to determine design suitability (high, moderate, or low), execution
(good, fair, or poor), and consistency of study results, with one exception: the eight
mathematical modeling studies were not rated on quality of execution because of the
lack of a grading system appropriate for the different mathematical model types included.
Overall, the quality of studies was low. Eleven studies addressed health or economic
benefits of more frequent screening compared with annual screening. Eight of these
were mathematical models that the CDC work group classified as having low suitability
because of uncertainty about the validity of the parameter estimates and questions
about the models’ generalizability. Two studies addressed intervals between HIV screening
or diagnostic tests in clinical settings, but did not directly address the acceptability
of more frequent than annual HIV screening among asymptomatic MSM. No studies addressed
harms associated with, or the feasibility of, conducting more frequent HIV screening
in clinical settings in the United States. Additional details about these studies
can be found elsewhere (
9
).
After deliberations that involved discussion, consensus building, and voting, the
CDC work group concluded that insufficient evidence exists in the published and unpublished
literature to warrant changing CDC’s current recommendation to offer HIV screening
at least annually to all sexually active MSM.
Expert Consultation Series Results
During August–December 2014, the CDC work group convened a series of consultations
with external subject matter experts, including clinicians, epidemiologists, academic
researchers, health department policy and program staff members, and members of the
MSM community, to 1) obtain their individual input on the results of the systematic
review and preliminary conclusions; 2) obtain the opinions and experiences of experts
from three public-sector HIV screening programs that provided more frequent than annual
HIV screening to MSM; and 3) identify studies missed in the literature review or data
that could be analyzed in the future to inform recommendations about HIV screening
frequency.
Postconsultation analysis of the individual feedback from experts revealed that most
believed the literature was insufficient to conclude that more frequent screening
had demonstrated benefits over annual screening but that the scientific and programmatic
evidence suggested that some MSM would be willing to be screened more frequently.
Experts from health departments already implementing more frequent than annual screening
described benefits of their programs, including decreases in the proportion of MSM
with undiagnosed HIV infection. Experts also individually agreed that the estimates
from the mathematical models suggest a benefit to more frequent screening, particularly
in jurisdictions providing prompt, high-quality access to HIV medical care, where
early treatment with ART decreases infectiousness and would likely decrease the number
of new HIV infections in sex or drug-using partners. In addition, individual experts
stressed the importance of the cost-effectiveness modeling studies, which estimated
that more frequent screening, compared with annual screening, would be more cost-effective
by averting new HIV infections (incremental cost-effectiveness ratio, range = cost-saving
– $138,200/quality-adjusted life year) (9). Finally, most experts stated that mathematical
models do not provide sufficient evidence to warrant by themselves a change in the
guideline, because of limitations in their study design, and that additional studies
are needed to update the current recommendation.
Recommendations
CDC concludes that the evidence, programmatic experience, and expert opinions are
insufficient to warrant changing the current recommendation (annual screening for
MSM) to more frequent screening (every 3 or 6 months). Therefore, CDC’s 2006 recommendation
for HIV screening of MSM is unchanged; providers in clinical settings should offer
HIV screening at least annually to all sexually active MSM. Clinicians can also consider
the potential benefits of more frequent HIV screening (e.g., every 3 or 6 months)
for some asymptomatic sexually active MSM based on their individual risk factors,
local HIV epidemiology, and local policies (
9
). Additional research is needed to establish the individual- or community-level factors
that might increase the risk for HIV acquisition for MSM and merit more frequent HIV
screening. For MSM who are prescribed preexposure prophylaxis, HIV testing every 3
months and immediate testing whenever signs and symptoms of acute HIV infection are
reported (
10
) is indicated. MSM who experience a specific high-risk sexual exposure or have symptoms
of recent HIV infection should seek immediate HIV testing, and clinicians should be
alert for the symptoms of acute HIV infection and provide appropriate diagnostic testing.
CDC encourages researchers to conduct studies to evaluate the benefits and harms of
more frequent screening for MSM. Findings from these studies will inform future assessment
of recommendations. CDC will continue to monitor the evidence on the effectiveness
of various HIV screening intervals and consider the need to revise current recommendations
in light of new evidence.