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Volume 10, Number 4—April 2004


Maternal Malaria and Perinatal HIV Transmission, Western Kenya1,2

John G. Ayisi*†, Anna M. van Eijk*†, Robert D. Newman‡Comments to Author , Feiko O. ter Kuile*†‡, Ya Ping Shi*‡, Chunfu Yang‡, Margarette S. Kolczak‡, Juliana A. Otieno§, Ambrose O. Misore§, Piet A. Kager†, Renu B. Lal‡, Richard W. Steketee‡, and Bernard L. Nahlen‡¶
Author affiliations: *Centre for Vector Biology and Control Research, Kenya Medical Research Institute, Kisumu, Kenya; †University of Amsterdam, Amsterdam, The Netherlands; ‡Centers for Disease Control and Prevention, Atlanta, Georgia, USA; §Ministry of Health, Kisumu, Kenya; ¶World Health Organization, Geneva, Switzerland

Main Article

Table 3

Multivariate analysis of risk factors for perinatal HIV transmission, western Kenya, 1996–2001

Adjusted relative risks (ARR) for perinatal HIV transmissiona
All womenb, N = 454
Placental malaria–negative, n = 348
Placental malaria–positiveb, n = 107
ARR (95% CI) p ARR (95% CI) p ARR (95% CI) p
Log10 viral load
1.8 (1.6 to 2.1)
1.7 (1.4 to 2.0)
3.5 (2.5 to 4.8)
Episiotomy or perineal tear
1.6 (1.2 to 2.1)

4.8 (2.3 to 9.7)
Low birth weight

1.9 (1.1 to 3.2)

Gravidity <3 versus >3

1.8 (1.2 to 2.8)

Placental malaria status



<10,000 parasites/μL
0.4 (0.2 to 0.6)b


>10,000 parasites/μL 0.7 (0.3 to 21.5)b NS N/A 2.0 (1.1 to 3.9) 0.04

a–, factor was not retained in the final model; CI, confidence interval; N/A, not applicable; NS, not significant.
bA significant interaction was found between viral load and placental malaria density (p = 0.02) in these analyses. The effect of this interaction on the relative risk for placental malaria is shown in Figures 1 and 2. All relative risks given in this table do not include this interaction but give a weighted average of the placental malaria effect at various levels of viral load.
cAn alternative model, in which placental malaria was fit as a binary variable (positive or negative), showed that placental malaria was protective for perinatal HIV transmission (relative risk 0.4, 95% CI 0.3 to 0.7, p < 0.001). In that model, log10 viral load and episiotomy or perineal tear remain independent risk factors.

Main Article

1This work was presented in part at the Epidemic Intelligence Service Conference, Centers for Disease Control and Prevention, April 2001, Atlanta, GA.

2Use of trade names is for identification only and does not imply endorsement by the Kenya Medical Research Institute or The Ministry of Health, Kenya, or by the Public Health Service, U.S. Department of Health and Human Services.