Research

Therapeutic and prophylactic effect of intermittent preventive anti-malarial treatment in infants (IPTi) from Ghana and Gabon

Jürgen May^1,2 , Samuel Adjei^2,3 , Wibke Busch¹ , Julian J Gabor^4,5 , Saadou Issifou^4,5 , Robin Kobbe¹ , Benno Kreuels^1,6 , Bertrand Lell^4,5 , Norbert G Schwarz^4,5 , Ohene Adjei² , Peter G Kremsner^4,5 and Martin P Grobusch^4,5,7,8

¹Research Group Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht Straße 74, D-20359 Hamburg, Germany

²Kumasi Centre for Collaborative Research in Tropical Medicine, Kumasi, Ghana

³Ministry of Health/Ghana Health Service, District Health Directorate, Agona, Ashanti Region, Ghana

⁴Medical Research Unit, Albert Schweitzer Hospital, Lambaréné, Gabon

⁵Department of Parasitology, Institute of Tropical Medicine, University of Tübingen, Germany

⁶Clinical Research Group, Bernhard Nocht Institute for Tropical Medicine, Germany

⁷Infectious Diseases Unit, Division of Clinical Microbiology and Infectious Diseases, National Health Laboratory Services, Johannesburg, South Africa

⁸School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa

author email corresponding author email

Malaria Journal 2008, 7:198doi:10.1186/1475-2875-7-198

Published:	1 October 2008

Abstract

Background

Intermittent preventive treatment in infants (IPTi) with sulphadoxine-pyrimethamine (SP) reduces the incidence of malaria episodes in young children. The exact mechanism by which the protective effect is mediated needs to be defined. This study aimed to investigate therapeutic, prophylactic, and possible exceeding effects of SP-based IPTi in two clinical trials.

Methods

Protective efficacies from two IPTi trials performed in Kumasi, Ghana, and Lambaréné, Gabon, were assessed for overlapping time series of 61 days. For six-months periods after each of three IPTi doses a multivariate Poisson regression model with the respective cohort as co-variate was generated and effect modification of protective efficacy with time strata was evaluated by log-likelihood tests.

Results

Protective efficacies were not significantly different between the two study cohorts. Study-cohort corrected protective efficacy was highest for the first 61 days after each IPTi application and decreased continuously. For the first 61 days after IPTi-1, IPTi-2, and IPTi-3 the protective efficacy was 71%, 44%, and 43%, respectively. A reduction of the malaria incidence rate was detectable for the first 60, 30 and 40 days after IPTi-1, IPTi-2 and IPTi-3 drug application, respectively. After IPTi-3 a higher risk for malaria could be seen after day 60. This effect was mainly based on the overwhelming influence of the Kumasi cohort.

Conclusion

The results suggest that SP-based IPTi mainly works through a therapeutic and prophylactic effect over 30 to 60 days after drug application and that a sustained effect beyond post-treatment prophylaxis might be very low.

Trial registration

Data analysis from clinical trials NCT ID # 00206739 (Kumasi Trial) and NCT ID # 00167843 (Lambaréné Trial), http://www.clinicaltrials.gov webcite.