Vol.1, No.3, 164-166 (2011)
doi:10.4236/ojpm.2011.13021
C opyright © 2011 SciRes. Openly accessible at http://www.scirp.org/journal/OJPM/
Open Journal of Preventive Medicine
Examine a dynamic of mother-to-child transmission of
HIV in the population-based surveys
Rathavuth Hong1*, Rathnita Them2
1Measure Demographic and Health Survey, ICF Macro, Calverton, USA;
*Corresponding Aut h o r :
2College of Health and Human Services, George Mason University, Fairfax, USA.
Received 29 June 2011; revised 23 September 2011; accepted 14 October 2011.
ABSTRACT
The main source of HIV infection in young chil-
dren is of their mothers, during pregnancy, la-
bor and delivery, or by breastfeeding. The rate
of HIV transmission from infected mothers to
their newborn children varies from 15% to 40%
with one-thirds of these infections was through
breastfeeding. This paper examines cross-sec-
tional population-based survey data of HIV test
results among mothers and their children in
Uganda, Swaziland to estimates of mother-to-
child transmission (MTCT) rate of HIV infection.
The prevalence of HIV among women aged 15 -
49 who gave birth in the past 5 years in Uganda
is 7.3%, and in Swaziland is 37.9%. The HIV
prevalence of children who mothers were HIV
positive were very similar: 10.3% in Uganda and
11.5 % in Swaziland. This association represents
the crude rate of MTCT in these two countries at
the time of the survey. Presence of HIV antibody
in early age (0 - 11 months) is due to both true
infection and passive antibody from mothers.
The seroconversion dropped nearly half in the
second year of age which was likely that many
of these children died before reaching the age
of 12 - 23 months and passive antibody were
gradually cleared at this point. This analysis
demonstrated that cross-sectional data can be
used to estimate indirectly the magnitude and
dynamic of MTCT.
Keywords: HIV/AIDS; Mother-to-Child;
Transmiss ion; Demographic and Health Survey;
Uganda; Swaziland
1. INTRODUCTION
The source of HIV infection in young children is
overwhelming of their mothers, during pregnancy, labor
and delivery, o r by breastfeeding. In the region where the
rate of HIV infection among pregnant women is very high,
for example exceeds 35%, HIV/AIDS infection contrib-
utes to as high as 42% of child mortality [1]. In develop-
ing countries, the rate of HIV transmission from infected
mothers to their newborn children varies from study to
study, and is estimated from about 15% to 40%. Among
those children who are infected HIV through the trans-
mission from their mothers, one-third received the virus
through breastfeeding [2].
We examine whether data on HIV testing in the
cross-sectional data such as population-based survey
provide good estimates of mother-to-child transmission
(MTCT) rate of HIV infection. The testing procedure
used two ELISAs parallel testing algorithm according to
WHO testing algorithm. All discordant samples were
subjected to a second round of testing using both tests.
The discordances from the second round are “indeter-
minate” and were then subjected to a third confirmatory
Western-Blot test. The Western-Blot result was consid-
ered final for the indeterminate samples.
2. METHODS
2.1. Data
We used data from the 2004-2005 Uganda HIV/AIDS
Sero Behavioural Survey (UHSBS) and from the 2006
Swaziland Demographic and Health Survey (SDHS).
These are national representative household surveys that
include HIV testing among children and adults. UHSBS
tested HIV among 8,374 children aged 0 - 59 months,
10,227 women age 15 - 59 years, and 8,298 men age 15 -
59 years in a random sample of 9,529 households across
the country. Information on birth history from the women
questionnaire was used to establish the link between
mothers and her biological children for the analysis of
this study.
2.2. Statistical Methods
Statistical analysis was performed using Stata 10.0

R. Hong et al. / Open Journal of Preventive Medicine 1 (20 11) 164-166
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Table 1. Association of children’s HIV status with mother’s HIV status, Uganda AIS 2004-2005 and Swaziland DHS 2007.
Uganda (0 - 59 months) Swaziland (24 - 59 months)
Variable Percentage HIV positive Number of children Percentage HIV positive Number of children
Mother’s HIV status
Negative 0.14 6607 0.79 345
Positive 10.25 364 11.52 176
Not tested/missing 0.76 1403 6.57 306
Total 0.68 8374 5.20 827
Table 2. Association of children’s HIV status with mother’s HIV status, by age of the child, Uganda AIS 2004-2005.
Mother HIV's status
Child's age (month) HIV negative HIV positive Unknown, died Unknown, survived Number
0-11 0.00 19.44 0.00 3.02 1631
12-23 0.47 10.24 0.00 0.00 1484
24-35 0.26 14.52 6.33 0.46 1667
36-47 0.00 6.37 6.35 0.43 1742
48-59 0.00 2.51 3.35 0.37 1849
Total 0.14 10.25 4.40 0.54 0.68
Number 6607 364 80 1323 8374
(Stata Corp., College Station, TX). Bivariate analyses
were conducted to identify the relationship of the
HIV-positive status between the children and the moth-
ers at the time of the survey, and the HIV prevalence
among the children by age group.
3. RESULTS
In the 2004-2005 Uganda HIV/AIDS Sero-Behav-
ioural Survey (UHSBS), 8,374 children age 0 - 59
months from a random sample of 9,529 households were
tested for HIV virus with valid test results [3]. The
prevalence of HIV infection in women aged 15 - 49 is
7.5%, in women aged 15 - 49 who gave birth in the 5
years before the survey is 7.3%, and in children age 0 -
59 months was 0.7%. In the 2006 Swaziland Demo-
graphic and Health Survey (SDHS), only 827 children
age 24 - 59 months were tested for HIV [4], of whom
5.2% were positive. In Swaziland the HIV prevalence is
31.1 percent among all women aged 15 - 49: 37.9%
among women who gave birth in the last 5 years and
26.0% among those who did not.
In UHSBS, 83% of HIV tested children, their bio-
logical mothers were also tested for HIV with valid test
results; 16% of the children, their mothers were not
tested or results were missing, or they were absent at the
time of testing; and abou t 1 percent of the children, their
mothers died before the survey. In Swaziland, 63% of
HIV tested children; their biological mothers were also
tested for HIV with valid test results available. In spite
of differences in prevalence of adult women and children
less than 5 founded in the two surveys, the HIV preva-
lence of children who mothers were HIV positive were
very similar: 10.3% in Uganda and 11.5% in Swaziland.
Results in Table 1 show strong relationship between HIV
positive status of the ch ildren and HIV positive status of
their biological mother. Nonetheless, there were a small
number of children (0.14% in Uganda and 0.79% in
Swaziland) who were tested positive for HIV, whereas
their biological mothers were tested negative for HIV.
This observed discordance could caused by false posi-
tive (among the children) and false negative (among the
mothers); or by HIV infection afterbirth in children, for
example by unsterile or used syringes and needles. The
association between HIV positive mother and HIV posi-
tive children repr esents the crude rate of MTCT in these
two countries at the time of the survey. At the time of
study the preventive MTCT (PMTCT) programs were
implemented only in some part of these two countries.
However, data on breastfeeding and on PMTCT program
is not available in these surveys; and attrition of breast-
feeding and impact of PMTCT on the transmission rate
are unknown.

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4. DISCUSSION
In these cross-sectional data, it is usually not possible
to establish a longitudinal association of HIV infection
in children and their mothers. Nonetheless, in Uganda
where the sample is quite large and includes children age
from 0 - 4 years old, the HIV test results among these
children can be estimated by age group of 0 - 11, 12 - 23,
24 - 35, 36 - 47, 48 - 59 months (age in single month is
not available) in order to understand some dynamic of
the infection.
About 19.4% of children aged 0 - 11 months of the
HIV positive mothers were tested positive. Presence of
HIV antibody in early age is due to both true infection
and passive antibody from mothers. The seroconversion
among children aged 12 - 23 months dropped nearly half
to only 10.2 %. It was very likely that these children had
the same positive rate as those aged 0 - 11 months, when
they were at that age group. Therefore this drop in sero-
conversion could be a result of (1) many infected chil-
dren were died before reaching the age of 12 - 23
months and (2) children were tested positive due to pas-
sive antibody from the mothers were gradually cleared
of this passive antibody. Study elsewhere also indicates
that children who are HIV positive after birth, about
23% became seronegative when they are nine months
old [5]. The proportion of children aged 24 - 35 months
tested positive increased to 14.5%, indicating that some
children newly infected at this age, most likely through
breast feeding. The prevalence decreased to 6.3% then to
4.4% among children age 36 - 47 months and 48 -59
months respectively as infected children continued to die
and exit the cohort. It is very unlikely that the passive
antibody presence a fte r 24 months of age.
The lack of information on breastfeeding and PMTCT
program dwindle the ability to analyze the attrition of
breastfeeding and the impact of PMTCT on MTCT of
HIV virus; and the lack data on age in single month im-
pede the prospect of decomposing positive rate by
smaller age group or performing survival analysis of
infected children. Nonetheless, this analysis demon-
strated that cross-sectional data can be used to estimate
indirectly the magnitude and dynamic of MTCT.
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