Intermittent Preventive Treatment of Malaria Provides Substantial Protection against Malaria in Children Already Protected by an Insecticide-Treated Bednet in Burkina Faso: A Randomised, Double-Blind, Placebo-Controlled Trial

Abstract

A randomized trial reported by Diadier Diallo and colleagues shows that intermittent preventive treatment for malaria in children who are protected from mosquitoes using insecticide-treated bednets provides substantial protection from malaria.

Abstract

Background

Intermittent preventive treatment of malaria in children (IPTc) is a promising new approach to the control of malaria in areas of seasonal malaria transmission but it is not known if IPTc adds to the protection provided by an insecticide-treated net (ITN).

Methods and Findings

An individually randomised, double-blind, placebo-controlled trial of seasonal IPTc was conducted in Burkina Faso in children aged 3 to 59 months who were provided with a long-lasting insecticide-treated bednet (LLIN). Three rounds of treatment with sulphadoxine pyrimethamine plus amodiaquine or placebos were given at monthly intervals during the malaria transmission season. Passive surveillance for malaria episodes was established, a cross-sectional survey was conducted at the end of the malaria transmission season, and use of ITNs was monitored during the intervention period. Incidence rates of malaria were compared using a Cox regression model and generalized linear models were fitted to examine the effect of IPTc on the prevalence of malaria infection, anaemia, and on anthropometric indicators. 3,052 children were screened and 3,014 were enrolled in the trial; 1,505 in the control arm and 1,509 in the intervention arm. Similar proportions of children in the two treatment arms were reported to sleep under an LLIN during the intervention period (93%). The incidence of malaria, defined as fever or history of fever with parasitaemia ≥5,000/µl, was 2.88 (95% confidence interval [CI] 2.70–3.06) per child during the intervention period in the control arm versus 0.87 (95% CI 0.78–0.97) in the intervention arm, a protective efficacy (PE) of 70% (95% CI 66%–74%) ( p<0.001). There was a 69% (95% CI 6%–90%) reduction in incidence of severe malaria ( p = 0.04) and a 46% (95% CI 7%–69%) ( p = 0.03) reduction in the incidence of all-cause hospital admissions. IPTc reduced the prevalence of malaria infection at the end of the malaria transmission season by 73% (95% CI 68%–77%) ( p<0.001) and that of moderately severe anaemia by 56% (95% CI 36%–70%) ( p<0.001). IPTc reduced the risks of wasting (risk ratio [RR]  = 0.79; 95% CI 0.65–1.00) ( p = 0.05) and of being underweight (RR  = 0.84; 95% CI 0.72–0.99) ( p = 0.03). Children who received IPTc were 2.8 (95% CI 2.3–3.5) ( p<0.001) times more likely to vomit than children who received placebo but no drug-related serious adverse event was recorded.

Conclusions

IPT of malaria provides substantial protection against malaria in children who sleep under an ITN. There is now strong evidence to support the integration of IPTc into malaria control strategies in areas of seasonal malaria transmission.

Trial Registration

ClinicalTrials.gov NCT00738946

Please see later in the article for the Editors' Summary

Editors' Summary

Background

Malaria accounts for one in five of all childhood deaths in Africa and of the one million annual malarial deaths world-wide, over 75% occur in African children under 5 years old. Malaria also causes severe morbidity in children, such as anemia, low birth weight, and neurological problems, which compromise the health and development of millions of children living in malaria endemic areas. As much of the impact of malaria on African children can be effectively prevented, significant efforts have been made in recent years to improve malaria control, such as the implementation of intermittent preventive treatment of malaria.

Intermittent preventive treatment (IPT) involves administration of antimalarial drugs at defined time intervals to individuals, regardless of whether they are known to be infected with malaria, to prevent morbidity and mortality. IPT was initially recommended for pregnant women and recently this strategy was extended to include infants (IPTi). Now, there is also IPT of malaria in children (IPTc), which is designed to protect against malaria during the high malaria transmission season.

Why Was This Study Done?

Large clinical trials have shown that IPTc involving the administration of two to three doses of an antimalarial drug (sulphadoxine pyrimethamine [SP] and artesunate [AS] or amodiaquine [AQ]) during the high malaria transmission season effectively reduces the incidence of malaria. However, these studies were conducted in countries where the use of insecticide-treated bednets—an intervention that provides at least 50% protection against morbidity from malaria and is the main tool used for malaria control in most of sub-Saharan Africa—was relatively low. Therefore, it is unclear whether IPTc will be as effective in children who sleep under insecticide-treated bednets as has been previously shown in communities where insecticide-treated bednet usage is low. So to determine the answer to this important question, the researchers conducted a randomized, placebo-controlled trial of IPTc with SP + AQ (chosen because of the effectiveness of this combination in a pilot study) in children who slept under an insecticide-treated bednet in an area of seasonal malaria transmission in Burkina Faso.

What Did the Researchers Do and Find?

The researchers enrolled 3,014 eligible children aged 3–59 months into a randomized double-blind, placebo-controlled trial during the 2008 malaria transmission season in Burkina Faso. All children were given a long-lasting insecticide-treated bednet at the start of the study with instructions to their family on the correct use of the net. Children were then randomized into two arms—1,509 were allocated to the intervention group and 1,505 to the control group—to receive three courses of IPTc with SP plus AQ or placebos given at monthly intervals during the peak malaria transmission season. The researchers monitored the incidence of malaria throughout the malaria season and also monitored the use of long-lasting insecticide-treated bednets throughout the study period. In addition, researchers conducted a cross-sectional survey in 150 randomly selected children every week and in every child enrolled in the trial 6 weeks after the last course of IPTc, to measure their temperature, height and weight, and blood hemoglobin and parasite count levels.

The number of children who slept under their long-lasting insecticide-treated bednet was similar in both arms. During the intervention period, the researchers found that the incidence of clinical malaria (defined as fever or a history of fever and the presence of at least 5,000 asexual forms of P. falciparum per microliter) was 2.88 in the control arm versus 0.87 in the intervention arm—giving a protective efficacy of 70%. There were 13 cases of severe malaria in the control arm and four in the IPTc arm—a 69% reduction in incidence. Additionally, all-cause hospital admission rate was reduced by 46%. At the end of the malaria transmission period, IPTc reduced the proportion of children infected with malaria parasites by 73% and reduced anemia by 33%. In addition, IPTc appeared to reduce the risk of wasting (risk ratio  = 0.79) and of being underweight (risk ratio  = 0.84). However, children who received IPTc were almost three times more likely to vomit than children who received placebo but there were no drug-related serious adverse events.

What Do These Findings Mean?

The results of this study show that in peak malarial transmission season in Burkina Faso, IPTc provides substantial additional protection against episodes of clinical malaria, severe malaria, and all-cause hospital admissions in children sleeping under long-lasting insecticide-treated bednets. In addition, intermittent preventive treatment of malaria with SP plus AQ appears to be safe for use in children.

Additional Information

Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000408.

• This topic is further discussed in two PLoS Medicine research articles: Dicko et al. and Bojang et al., and in a PLoS Medicine Perspective by Beeson

• Roll Back Malaria has information about malaria in children, including intervention strategies

• UNICEF also provides comprehensive information about malaria in children

• The Intermittent Preventive Treatment in Infants Consortium (ipti) provides information on intermittent preventive treatment in infants

• Roll Back Malaria has an information sheet on insecticide-treated bednets