Principles of Viral Load Monitoring in HIV Patients

 
Module 1:
Principles
 
of
 
Viral 
Load
 
Monitoring
 
Learning
 
Objectives
 
Understand the
 
dynamics
 
of
 
viral load during the course
of
 
HIV infection
Understand 
how 
viral load affects risk for
 
transmission
and
 
progression
 
of
 
HIV
Explain 
how 
viral load responds to 
antiretroviral 
therapy
(ART)
Identify treatment failure using viral
 
load
Describe
 
schedule
 
of
 
viral load
 
monitoring
 
Outline
 
Understanding 
Viral
 
Load
Viral 
Load and HIV
 
Infection
Disease
 
Progression
Disease
 
Transmission
Viral 
Load Measurement and
 
Reporting
Viral 
Load 
Response 
to 
ART
Treatment
 
Failure
Criteria
Routine 
and 
Targeted 
Viral 
Load
 
Monitoring
Schedule
 
of
 
Viral 
Load
 
Monitoring
 
Introduction: 
What 
is 
Viral 
Load?
 
(1)
Viral 
load 
is the 
concentration
 of
HIV 
RNA 
copies in
 
blood.
 
This 
is a
 
reflection
 of
 
ongoing
virus  
replication in a 
person’s
body.
 
Introduction: 
What 
is 
Viral 
Load?
 
(2)
 
Viral load 
is 
used 
as 
an indicator 
of:
Response 
to 
ART 
and risk for clinical disease
progression
Risk
 
of
 
transmission
 
of
 
HIV 
between 
sex
 
partners
Risk
 
of
 
transmission
 
of
 
HIV from mother to
 
child
Since 2013, WHO 
guidelines recommend
routine viral 
load 
testing 
for 
all 
HIV-infected
children 
and adults 
on
 
ART
 
DHHS 
Guidelines, 
2013; 
Murray 
et 
al, AIDS 
1999; 
Marschner 
et 
al, JID 
1998; 
Thiebaut 
et 
al, AIDS
 
2000
 
Viral
 
Load
 
during 
HIV
 
Disease
 
Acute infection:
 
Viral load rises rapidly and often 
to very 
high 
levels 
(>1 
million
 
c/ml)
6-12 
weeks 
after infection:
 
Immune 
response reduces viral load 
to 
steady 
level 
(“set
 
point”)
Set point 
predicts disease progress, higher 
set 
point indicates 
a 
more rapid 
progression to
 
AIDS
Without 
ART, 
viral load increases 
over 
several years, 
gradually 
and then more rapidly as
symptoms 
develop
 
www.youngdayschool.edu.uy
 
Progression 
to 
AIDS 
by 
Viral
 
Load
 
Background: 
VL 
& HIV
 transmission
 
Numerous studies 
have 
suggested 
that high viral 
loads
increase HIV transmission within 
a 
given
 
community
On an 
individual 
level, 
viral load has been 
shown 
to
strongly 
correlate 
with transmission
 
risk
Lon
g
 
k
n
o
w
n
 t
o
 b
e
 th
e
 
g
r
e
a
te
st
 p
r
e
d
icto
r 
o
f
 
m
ate
r
na
l
to 
child
 transmission
 
Viral
 
Load
 
and
 
Sexual
 Transmission
 
HIV 
viral 
load
 
(copies/ml)
 
Quinn 
et 
al., NEJM
 
2000
Rate 
of
t
r
a
n
smi
ss
i
on:
2.2 per 100
p
e
r
s
o
n
-
y
e
a
r
s
Zero
 
transmissions
 
Rate 
of
t
r
a
n
smi
ss
i
on:
23 per 100
person-years
 
Background: 
Treatment 
as
 
Prevention
 
HPTN 
052 
assessed 
virologically-linked 
HIV
transmission among 
stable, 
healthy 
serodiscordant
couples in 
which 
the infected 
partner 
had CD4 counts
ab
o
v
e
 th
e
 
A
R
T s
ta
r
tin
g
 poin
t
 i
n
 effec
t
 
at
 th
e
 ti
me
 o
f
 
th
e
trial
All 
linked 
HIV 
transmission 
events 
occurred 
in the 
early
months 
of 
treatment, prior 
to 
virologic
 
suppression
A 
linked 
transmission 
means that 
the 
virus 
was 
studied 
and
found to 
be 
the 
same
 
virus
No 
linked 
HIV 
transmission 
events 
occurred 
when HIV 
was
stably suppressed 
by 
ART 
in the 
index
 
participant
 
Cohen,
 
2016
 
Background: 
Treatment 
as 
Prevention
 
(2)
 
Additional studies 
(PARTNER 
1 
and 
2 
and Opposites
Attract) 
have 
added additional 
observations 
and assessed
linked 
HIV transmissions among
 
MSM
No (zero) 
linked 
transmissions from 
HIV-infected 
individuals
who 
are undetectable
VL 
assays 
used in these studies 
had 
variable upper end 
cut-off
values 
but 
all 
required 
a 
VL 
<
 200
 
copies/ml
 
Rodger 
2016; 
Bavinton 
2018; 
Rodger
 
2019
 
UNDETECTABLE 
=
 
UNTRANSMITTABLE
 
Undetectable 
means that 
the
amount of HIV 
in the 
blood 
is
too 
low 
to count 
on 
a 
viral 
load
test
Treatment 
as 
Prevention 
(TasP)
refers 
to 
using 
antiretroviral
therapy 
(ART) 
to 
prevent 
sexual
transmission of HIV
U=U is a 
global 
movement
about 
how 
effective 
treatment
as 
Prevention 
can be, 
if 
scaled
widely
 
There 
is 
effectively 
no 
risk 
of
sexual 
transmission of HIV when
the 
partner living 
with 
HIV has 
a
durably undetectable viral
 
load
 
UNDETECTABLE 
=
 
UNTRANSMITTABLE
 
Reduces 
shame and
 
fear
 
of
 
sexual transmission
Dismantles stigma in the 
community, 
health care 
setting,
and 
individually
Encourages 
and 
motivates 
people to begin treatment 
and
to be adherent to their treatment
Strengthens 
advocacy 
efforts 
for 
universal 
access to
 
care
 
UNDETECTABLE 
=
 
UNTRANSMITTABLE
Caveats
 
Requires
 
implementation
 
of
 
VL
 
testing
Requires 
quantification (VL< 
200
 
copies/ml)
Necessitates 
efficient
 
return
 
of
 
results to 
the
 
HIV
infected individual
Requires 
retesting 
at 
regular
 
intervals
Requires 
consistent adherence 
to 
maintain 
viral
suppression 
going
 
forward
Places
 
prevention
 of
 
transmission 
in 
the hands
of  the infected
 
individual
This 
can 
be both liberating 
and
 
burdensome
 
UNDETECTABLE 
=
 
UNTRANSMITTABLE
Caveats
 
Undetectable [or VL 
<
 
200
 
copies/ml
 
if
 
a
 
more
sensitive 
VL 
assay 
is 
used] 
is the 
goal 
to 
assure
that 
the 
individual 
will not 
transmit 
HIV via
sexual 
activity
This
 
cutoff
 
is 
distinct [and 
often 
different] 
than
the 
country 
specific 
goal 
for a 
good 
clinical
response 
to 
treatment [a 
low 
viral load] 
which 
is
commonly set 
at < 
1000
 
copies/ml
 
Viral
 
Load
 
Measurement
 
Viral load 
can 
be
measured 
using whole
blood, plasma, or
 
dried
blood spots
Assays 
quantify HIV viral
load 
as RNA 
copies/ml,
also 
reported 
on 
a 
log
10
scale
Lower 
limits of detection
vary 
with 
assays 
(e.g.<20,
50, 400
 
copies/ml)
Optimal results include
target 
not detected, or the
lower
 
limits
 
of
 
detection
 
Viral
 
Load
 
Log
 
Scale
 
Viral 
RNA
 
copies/ml
of
 
plasma
Log-scale: 
a
 
1-log
change 
= 
10-fold
change
Viral 
load 
changes
less 
than 
1 
log 
are
generally 
not 
of
clinical
 
significance
 
Virologic 
Response 
to
 
ART
 
ART 
prevents 
HIV 
replication 
by 
inhibiting
viral 
enzymes 
causing 
the 
viral load 
to
 
decline
The
 
goal
 
of
 
treatment is 
to 
achieve 
a
suppressed viral load:
Associated 
with 
better 
clinical
 
outcomes
Lower
 
risk
 
of
 
HIV transmission
Persistent 
viral 
replication 
while taking 
ART
can 
lead 
to 
resistance 
to one or 
more
antiretrovirals 
(ARVs)
 
Virologic 
Response 
to
 
ART
 
Viral 
load
 
<1000
 
copies/ml
 
has
 
been
is
considered 
acceptable 
in 
many
countries
 
Risk 
of 
transmission 
and 
disease
progression is
 
low
Regarding clinical endpoints 
and
reduced risk 
of viral 
resistance, 
even
lower 
is
 
better
In most patients 
taking 
ART, 
the 
viral
load 
should 
be <1000 
copies/ml after
6 
months 
of
 
treatment
Those 
with high baseline 
viral load,
such 
as 
infants, may take 
longer 
to
achieve
 
suppression
 
DHHS 
Guidelines, 
2013; 
Tsibris and Hirsch, PPID 
2010; 
Kaufmann 
et 
al., Arch Intern 
Med
 
2003
VL 
target: 
<1000
 
copies/ml
 
Be
t
t
er
 
outcome
Lower risk
 
of
t
r
a
n
s
m
i
ss
i
on
 
Viral Load
 
Response
 
Country
 
Guidelines
Insert 
country 
guidelines regarding 
what 
is 
an acceptable
VL 
response 
to
 
treatment
 
Immunologic 
and Clinical 
Responses 
to 
ART
with Viral
 
Suppression
 
With viral
 
suppression:
CD4 count increases
50 
to
 
150
 
cells/µl
 
expected 
in the 
1st
 
year
50 
to 100 
cells/µl expected 
in the 2nd 
year
Improved 
clinical 
status 
(weight 
gain,
resolution
 
of
 
diarrhea, 
no new
opportunistic 
infections)
 
Viral Load Suppression 
Allows 
for CD4
Recovery
 
Monitoring for 
Treatment
 
Failure
 
Treatment 
failure 
can 
be defined 
using 
the
following
 
criteria:
 
Resource-limited 
settings 
have 
relied on suboptimal
clinical and 
immunologic
 
methods
May 
not 
detect early
 
failure
Some 
with clinical 
or 
immunologic 
failure 
may 
not
actually 
have 
virologic
 
failure
 
 
Clinical
 
 
Immunologic
 
 
Virologic
 
How 
Does Virologic Monitoring Compare
 
to
Clinical or 
Immunologic 
Monitoring?
 
How 
Does Virologic Monitoring Compare
to Clinical or 
Immunologic 
Monitoring?
 
Virologic monitoring 
has 
greater 
sensitivity 
and 
positive
predictive 
value 
for detecting treatment failure 
than clinical
or CD4
 
criteria.
Increased Sensitivity
Earlier
 detection
Timely 
regimen
 
changes
Decreased 
time 
with
 
ongoing
viral
 
replication
May prevent 
drug 
resistance
and decrease transmission
 
risk
Higher 
Positive 
Predictive
 
Value
Less
 misclassification
Helps 
prevent 
unnecessary
switches to 
second-line 
ART 
in
those 
who 
are 
actually
suppressed
 
Kantor 
et 
al., CID 
2009; Rawizza 
et 
al., CID 
2011; 
Mermin et 
al., 
BMJ
 
2011
 
Viral Load, CD4 and Clinical Criteria for
Treatment
 
Failure
 
Viral 
load 
(virologic monitoring) 
is 
more 
sensitive 
and 
reliable 
for
determining 
treatment failure 
for 
those 
on 
ART 
compared 
to clinical
monitoring 
or 
CD4 criteria (immunologic
 
monitoring).
 
www.slideshare.net
 
Criteria for 
Treatment 
Failure 
Determined 
by
Viral
 
Load
Virologic 
treatment
 
failure:
Persistent 
plasma viral load 
over 
the
 
country
–specific guidelines 
when 
measured at least 
6
months after 
starting
 
ART
“Persistent” 
defined 
as 
>
2 
consecutive 
viral load
results 
3 
months 
apart 
with adherence 
support
between 
measurements
 
Routine 
and 
Targeted 
Viral Load
 
Monitoring
 
Routine Viral 
Load
Monitoring
 
Ideally, 
viral load should 
be
measured 
at 
regular 
intervals
for all those 
on 
ART 
to
monitor response 
to
treatment 
and 
for early
detection 
of 
treatment
 
failure
 
Targeted 
Viral 
Load
Monitoring
 
In settings where routine
viral load is 
not 
feasible 
or
available, 
viral load testing
should 
be 
used 
to 
confirm
treatment failure if suspected
by 
CD4 or 
clinical
 
criteria
 
WHO 2016 Guidelines: Viral Load
 
Schedule
 
Check 
viral 
load 6 
months after 
ART
 
initiation
If
 
acceptable, then 
repeat 
testing 
6 
months 
later,
then 
repeat 
at least 
every 12
 
months
If
 
viral load is 
elevated, provide 
adherence 
support
and 
re-check 
in 
3
 
months
Virologic failure
 
only
 
if
 
repeat 
viral load result 
is
still 
elevated 
after adherence
 
support
Those 
with high 
baseline viral load, 
such 
as
infants, 
young children 
and some 
adults, may
take 
longer 
to 
achieve
 suppression
 
Routine 
and 
Targeted 
Viral Load Monitoring
Adapted from WHO Guidelines
 
Adherence 
Interventions 
Improve
Suppression
 
of
 
Viral
 
Load
 
53% 
of 
those
with 
initial
 
VL
>
1,000 copies/ml
achieved
 
virologic
suppression
 
after
early viral 
load
testing and 
a
targeted
 
intensive
adherence
intervention
 
Orrell 
et 
al., 
Antivir 
Ther
 
2007
 
Enhanced
 
Adherence
 
Counseling
 
Enhanced 
Adherence Counseling 
is a 
continual 
and repeated 
process 
that
involves:
 
Repeat 
Steps 1-4 
during 
follow-up
 sessions.
 
Step 1: 
A 
structured
assessment 
of
 
current
level 
of
 
adherence
 
Step 2: Exploration 
of
 
the
specific barriers 
the
patient must
 
overcome
 
Step 3: Motivating
 
and
assisting patients 
to
identify 
solutions 
and
address
 
barriers
 
Step 4: Develop and
individualized
 
adherence
intervention
 
plan
 
A
c
h
ievi
n
g
 
G
oo
d
 
A
d
h
e
r
e
n
ce
 
Adherence sessions should 
be repeated 
until
good 
adherence 
is
 
achieved
Once 
good 
adherence is 
achieved, 
set 
a date for
repeat 
viral 
load 
measurement after 
3 
months
of  
good 
adherence 
and 
provide 
to
 
patient
 
Viral Load Monitoring:
Not 
Too 
Much, 
Not 
Too
 
Little
 
More evidence is needed 
to 
determine 
the optimal
schedule 
for viral load 
monitoring.
Monitoring too often:
Resource 
intensive, 
costly and 
may 
not 
contribute 
to
improved 
patient
 
outcomes
If 
improperly implemented 
may 
lead to 
premature regimen
change 
(e.g. 
viral 
load 
testing prior 
to 
expected time 
of
suppression, 
or repeat 
viral 
load 
testing without 
improvement
in
 adherence)
Infrequent monitoring 
may 
lead 
to 
late detection
of  treatment 
failure,
 
progression
 
of
 
disease, 
or
HIV  transmission
In 
partially 
adherent 
patients 
delayed 
viral 
load 
testing 
may
allow 
for emergence of 
drug
 
resistance
 
Schedule 
for 
Routine 
Viral 
Load
 
Monitoring
Adults (Non-Pregnant or Breastfeeding
 
)
 
Fill 
in 
schedule according 
to 
national
 
guidelines
 
Schedule 
for 
Routine 
Viral Load Monitoring
 
Fill 
in 
schedule according 
to 
national
 
guidelines
Children 
and Adolescents on
 
ART
 
Schedule 
for 
Routine 
Viral Load Monitoring
 
Fill 
in 
schedule according 
to 
national
 
guidelines
Pregnant or Breastfeeding 
Women 
on
 
ART
 
Role
 
of
 
CD4 Count
 
Tests
 
CD4 test at baseline, 
when 
returning 
to 
care
after 
a 
treatment 
interruption, 
or when
presenting 
with a new or 
problem assists 
in
determining 
the
 
degree
 
of
 
immune
 
suppression
CD4 
may 
guide 
and 
prioritize 
workup 
and assist
in 
decisions about 
prophylaxis
Routine 
CD4 tests are 
no 
longer
 
necessary
 
CD4 Count
 
Testing
 
Fill 
in 
national guidelines 
on CD4 
count
 
testing
 
Knowledge
 
Check
 
Question
 
1
 
Which
 
of
 
the following patients has the
highest
 
risk
 
of
 
transmitting HIV during
 
an
unprotected 
sexual
 
act?
 
A.
On 
ARVs 
with 
VL 
= 
10,000
 
copies/ml
B.
Not 
on 
ARVs 
with 
VL 
= 
100,000
 
copies/ml
C.
On 
ARVs 
with 
VL 
< 20
 
copies/ml
D.
On 
ARVs 
with 
VL 
= 
2,000
 
copies/ml
 
Answer
 
Which
 
of
 
the following patients has the
highest
 
risk
 
of
 
transmitting HIV during
 
an
unprotected 
sexual
 
act?
 
A.
On 
ARVs 
with 
VL 
=
 
10,000
B.
Not on 
ARVs 
with 
VL =
 
100,000
C.
On 
ARVs 
with 
VL 
<
 
20
D.
On 
ARVs 
with 
VL 
=
 
2,000
 
Question
 
2
 
Patient 
A 
has 
a VL = 3,500 
after 
6 
weeks 
on
ART. 
This 
represents treatment
 
failure.
 
A.
True
B.
False
 
Answer
 
Patient 
A 
has 
a VL = 3,500 
after 
6 
weeks 
on
ART. 
This 
represents treatment
 
failure.
 
A.
True
B.
False
 
Question
 
3
 
Patient 
B 
has 
an 
undetectable 
VL 
after 
6
months on 
ART. 
When 
is 
the next 
VL
 
due?
 
1.
Not 
needed
2.
1
 
year
3.
6
 
months
4.
3
 
months
 
Answer
 
Patient 
B 
has 
an 
undetectable 
VL 
after 
6
months on 
ART. 
When 
is 
the next 
VL
 
due?
 
1.
Not 
needed
2.
1
 
year
3.
6
 
months
4.
3
 
months
 
Summary
 
Viral load predicts 
progression of 
disease in 
an 
individual, 
and 
onward
transmission 
of 
HIV 
to 
sex 
partners or 
from 
mother to
 
baby
In most 
individuals, 
viral load will drop 
to 
below levels 
detectable 
by
viral load blood tests after 
6 months of
 
ART
Viral load testing is 
the preferred method 
for detecting treatment failure
for 
ART 
patients 
and 
should 
be 
checked 
after 
6 months on
 
ART
Follow 
country-specific 
guidelines
 
for
 
the
 
viral load 
that 
indicates
acceptable 
response 
to 
ART
Virologic 
treatment failure
: 
persistent 
(
>
2 
viral load tests 
3 months
apart 
with adherence 
support 
in between 
) 
plasma viral load ≥1000
copies/ml 
when 
measured after 
at 
least 
6 months of
 
ART
 
Questions?
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Explore the dynamics of viral load in HIV infection, its impact on transmission and disease progression, response to antiretroviral therapy, identification of treatment failure, and monitoring schedules. Understand the significance of viral load testing in managing HIV patients effectively.


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  1. Module 1: Principles of Viral Load Monitoring

  2. Learning Objectives Understand the dynamics of viral load during the course of HIV infection Understand how viral load affects risk for transmission and progression of HIV Explain how viral load responds to antiretroviral therapy (ART) Identify treatment failure using viral load Describe schedule of viral load monitoring

  3. Outline Understanding Viral Load Viral Load and HIV Infection Disease Progression Disease Transmission Viral Load Measurement and Reporting Viral Load Response to ART Treatment Failure Criteria Routine and Targeted Viral Load Monitoring Schedule of Viral Load Monitoring

  4. Introduction: What is Viral Load? (1) Viral load is the concentration of HIV RNA copies in blood. This is a reflection of ongoing virus replication in a person s body.

  5. Introduction: What is Viral Load? (2) Viral load is used as an indicator of: Response to ART and risk for clinical disease progression Risk of transmission of HIV between sex partners Risk of transmission of HIV from mother to child Since 2013, WHO guidelines recommend routine viral load testing for all HIV-infected children and adults on ART DHHS Guidelines, 2013; Murray et al, AIDS 1999; Marschner et al, JID 1998; Thiebaut et al, AIDS 2000

  6. Viral Load during HIV Disease Acute infection: Viral load rises rapidly and often to very high levels (>1 million c/ml) 6-12 weeks after infection: Immune response reduces viral load to steady level ( set point ) Set point predicts disease progress, higher set point indicates a more rapid progression to AIDS Without ART, viral load increases over several years, gradually and then more rapidly as symptoms develop www.youngdayschool.edu.uy

  7. Progression to AIDS by Viral Load

  8. Background: VL & HIV transmission Numerous studies have suggested that high viral loads increase HIV transmission within a given community On an individual level, viral load has been shown t o strongly correlate with transmission risk Long known to be the greatest predictor of maternal to child transmission

  9. Viral Load and Sexual Transmission Rate of transmission: 23 per 100 person-years Rate of transmission: 2.2 per 100 person-years Zero transmissions HIV viral load(copies/ml) Quinn et al., NEJM2000

  10. Background: Treatment as Prevention HPTN 052 assessed virologically-linked HIV transmission among stable, healthy serodiscordant couples in which the infected partner had CD4 counts above the ART starting point in effect at the time of the trial All linked HIV transmission events occurred in the early months of treatment, prior to virologicsuppression A linked transmission means that the virus was studied and found to be the same virus No linked HIV transmission events occurred when HIV was stably suppressed by ART in the index participant Cohen,2016

  11. Background: Treatment as Prevention (2) Additional studies (PARTNER 1 and 2 and Opposites Attract) have added additional observations and assessed linked HIV transmissions among MSM No (zero) linked transmissions from HIV-infected individuals who are undetectable VL assays used in these studies had variable upper end cut-off values but all required a VL < 200 copies/ml Rodger 2016; Bavinton 2018; Rodger 2019

  12. UNDETECTABLE = UNTRANSMITTABLE Undetectable means that the amount of HIV in the blood is too low to count on a viral load test Treatment as Prevention (TasP) refers to using antiretroviral therapy (ART) to prevent sexual transmission of HIV U=U is a global movement about how effective treatment as Prevention can be, if scaled widely There is effectively no risk of sexual transmission of HIV when the partner living with HIV has a durably undetectable viral load

  13. UNDETECTABLE = UNTRANSMITTABLE Reduces shame and fear of sexual transmission Dismantles stigma in the community, health care setting, and individually Encourages and motivates people to begin treatment and to be adherent to their treatment Strengthens advocacy efforts for universal access to care

  14. UNDETECTABLE = UNTRANSMITTABLE Caveats Requires implementation of VL testing Requires quantification (VL< 200 copies/ml) Necessitates efficient return of results to the HIV infected individual Requires retesting at regular intervals Requires consistent adherence to maintain viral suppression going forward Places prevention of transmission in the hands of the infected individual This can be both liberating and burdensome

  15. UNDETECTABLE = UNTRANSMITTABLE Caveats Undetectable [or VL < 200 copies/ml if a more sensitive VL assay is used] is the goal to assure that the individual will not transmit HIV via sexual activity This cutoff is distinct [and often different] than the country specific goal for a good clinical response to treatment [a low viral load] which is commonly set at < 1000 copies/ml

  16. Viral Load Measurement Viral load can be measured using whole blood, plasma, or dried blood spots Assays quantify HIV viral load as RNA copies/ml, also reported on a log10 scale Lower limits of detection vary with assays (e.g.<20, 50, 400 copies/ml) Optimal results include target not detected, or the lower limits of detection

  17. Viral Load Log Scale Viral RNA copies/ml of plasma Log-scale: a 1-log change = 10-fold change Viral load changes less than 1 log are generally not of clinicalsignificance Log10scale Copies/ml 1.0 10 1.5 32 2.0 100 2.5 316 3.0 1,000 3.5 3,162 4.0 10,000 4.5 31,623 5.0 100,000 5.5 316,228

  18. Virologic Response to ART ART prevents HIV replication by inhibiting viral enzymes causing the viral load to decline The goal of treatment is to achieve a suppressed viral load: Associated with better clinical outcomes Lower risk of HIV transmission Persistent viral replication while taking ART can lead to resistance to one or more antiretrovirals (ARVs)

  19. Virologic Response to ART Viral load <1000 copies/ml has beenis considered acceptable in many countries Risk of transmission and disease progression is low Regarding clinical endpoints and reduced risk of viral resistance, even lower is better In most patients taking ART, the viral load should be <1000 copies/ml after 6 months of treatment Those with high baseline viral load, such as infants, may take longer to achieve suppression VL target: <1000 copies/ml Better outcome Lower riskof transmission DHHS Guidelines, 2013; Tsibris and Hirsch, PPID 2010; Kaufmann et al., Arch Intern Med 2003

  20. Viral Load Response Country Guidelines Insert country guidelines regarding what is an acceptable VL response to treatment

  21. Immunologic and Clinical Responses to ART with Viral Suppression With viral suppression: CD4 count increases 50 to 150 cells/ l expected in the 1st year 50 to 100 cells/ l expected in the 2nd year Improved clinical status (weight gain, resolution of diarrhea, no new opportunistic infections)

  22. Viral Load Suppression Allows for CD4 Recovery

  23. Monitoring for Treatment Failure Treatment failure can be defined using the following criteria: Clinical Immunologic Virologic Resource-limited settings have relied on suboptimal clinical and immunologic methods May not detect early failure Some with clinical or immunologic failure may not actually have virologic failure

  24. How Does Virologic Monitoring Compare to Clinical or Immunologic Monitoring? to Clinical or Immunologic Monitoring? How Does Virologic Monitoring Compare Virologic monitoring has greater sensitivity and positive predictive value for detecting treatment failure than clinical or CD4 criteria. Increased Sensitivity Higher Positive Predictive Value Earlier detection Timely regimen changes Decreased time withongoing viral replication May prevent drug resistance and decrease transmissionrisk Less misclassification Helps prevent unnecessary switches to second-line ART in those who are actually suppressed Kantor et al., CID 2009; Rawizza et al., CID 2011; Mermin et al., BMJ 2011

  25. Viral Load, CD4 and Clinical Criteria for Treatment Failure Viral load (virologic monitoring) is more sensitive and reliable for determining treatment failure for those on ART compared to clinical monitoring or CD4 criteria (immunologic monitoring). www.slideshare.net

  26. Criteria for Treatment Failure Determined by Viral Load Virologic treatment failure: Persistent plasma viral load over the country specific guidelines when measured at least 6 months after starting ART Persistent defined as >2 consecutive viral load results 3 months apart with adherence support between measurements

  27. Routine and Targeted Viral Load Monitoring Routine Viral Load Monitoring Targeted Viral Load Monitoring Ideally, viral load should be measured at regular intervals for all those on ART to monitor response to treatment and for early detection of treatmentfailure In settings where routine viral load is not feasible or available, viral load testing should be used to confirm treatment failure if suspected by CD4 or clinical criteria

  28. WHO 2016 Guidelines: Viral Load Schedule Check viral load 6 months after ART initiation If acceptable, then repeat testing 6 months later, then repeat at least every 12 months If viral load is elevated, provide adherence support and re-check in 3 months Virologic failure only if repeat viral load result is still elevated after adherence support Those with high baseline viral load, such as infants, young children and some adults, may take longer to achieve suppression

  29. Routine and Targeted Viral Load Monitoring Adapted from WHO Guidelines

  30. Adherence Interventions Improve Suppression of Viral Load 53% of those with initial VL >1,000 copies/ml achieved virologic suppression after early viral load testing and a targeted intensive adherence intervention Orrell et al., Antivir Ther2007

  31. Enhanced Adherence Counseling Enhanced Adherence Counseling is a continual and repeated process that involves: Step 1: A structured assessment ofcurrent level ofadherence Step 4: Develop and individualizedadherence interventionplan Step 2: Exploration ofthe specific barriers the patient mustovercome Step 3: Motivatingand assisting patients to identify solutions and address barriers Repeat Steps 1-4 during follow-up sessions.

  32. Achieving Good Adherence Adherence sessions should be repeated until good adherence is achieved Once good adherence is achieved, set a date for repeat viral load measurement after 3 months of good adherence and provide to patient

  33. Viral Load Monitoring: Not Too Much, Not Too Little More evidence is needed to determine the optimal schedule for viral load monitoring. Monitoring too often: Resource intensive, costly and may not contribute to improved patient outcomes If improperly implemented may lead to premature regimen change (e.g. viral load testing prior to expected time of suppression, or repeat viral load testing without improvement in adherence) Infrequent monitoring may lead to late detection of treatment failure, progression of HIV transmission In partially adherent patients delayed viral load testing may allow for emergence of drugresistance disease, or

  34. Schedule for Routine Viral Load Monitoring Adults (Non-Pregnant or Breastfeeding ) Fill in schedule according to national guidelines

  35. Schedule for Routine Viral Load Monitoring Children and Adolescents on ART Fill in schedule according to national guidelines

  36. Schedule for Routine Viral Load Monitoring Pregnant or Breastfeeding Women on ART Fill in schedule according to national guidelines

  37. Role of CD4 Count Tests CD4 test at baseline, when returning to care after a treatment interruption, or when presenting with a new or problem assists in determining the degree of immune suppression CD4 may guide and prioritize workup and assist in decisions about prophylaxis Routine CD4 tests are no longer necessary

  38. CD4 Count Testing Fill in national guidelines on CD4 count testing

  39. Knowledge Check

  40. Question 1 Which of the following patients has the highest risk of transmitting HIV during an unprotected sexual act? A. On ARVs with VL = 10,000 copies/ml B. Not on ARVs with VL = 100,000 copies/ml C. On ARVs with VL < 20 copies/ml D. On ARVs with VL = 2,000 copies/ml

  41. Answer Which of the following patients has the highest risk of transmitting HIV during an unprotected sexual act? A. On ARVs with VL = 10,000 B. Not on ARVs with VL = 100,000 C. On ARVs with VL < 20 D. On ARVs with VL = 2,000

  42. Question 2 Patient A has a VL = 3,500 after 6 weeks on ART. This represents treatment failure. A. True B. False

  43. Answer Patient A has a VL = 3,500 after 6 weeks on ART. This represents treatment failure. A. True B. False

  44. Question 3 Patient B has an undetectable VL after 6 months on ART. When is the next VL due? 1. Not needed 2. 1 year 3. 6 months 4. 3 months

  45. Answer Patient B has an undetectable VL after 6 months on ART. When is the next VL due? 1. Not needed 2. 1 year 3. 6 months 4. 3 months

  46. Summary Viral load predicts progression of disease in an individual, and onward transmission of HIV to sex partners or from mother tobaby In most individuals, viral load will drop to below levels detectable by viral load blood tests after 6 months of ART Viral load testing is the preferred method for detecting treatment failure for ART patients and should be checked after 6 months on ART Follow country-specific guidelines for the viral load that indicates acceptable response to ART Virologic treatment failure: persistent (>2 viral load tests 3 months apart with adherence support in between ) plasma viral load 1000 copies/ml when measured after at least 6 months of ART

  47. Questions?

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