Sensitivity of Plasmodium falciparum to chlorproguanil in Gambian children after five years of continuous chemoprophylaxis

Health & Demographic Surveillance System Profile: Farafenni Health and Demographic Surveillance System in The Gambia

The Farafenni Health and Demographic Surveillance System (Farafenni HDSS) is located 170 km from the coast in a rural area of The Gambia, north of the River Gambia. It was set up in 1981 by the UK Medical Research Council Laboratories to generate demographic and health information required for the evaluation of a village-based, primary health care programme in 40 villages. Regular updates of demographic events and residency status have subsequently been conducted every 4 months. The surveillance area was extended in 2002 to include Farafenni Town and surrounding villages to support randomized, controlled trials. With over three decades of prospective surveillance, and through specific scientific investigations, the platform (population ≈ 50,000) has generated data on: morbidity and mortality due to malaria in children and during pregnancy; non-communicable disease among adults; reproductive health; and levels and trends in childhood and maternal mortality. Other information routinely collected includes causes of death through verbal autopsy, and household socioeconomic indicators. The current portfolio of the platform includes tracking Millennium Development Goal 4 (MDG4) attainments in rural Gambia and cause-of-death determination.

Intermittent preventive treatment for malaria in children living in areas with seasonal transmission

BACKGROUND

In malaria endemic areas, pre-school children are at high risk of severe and repeated malaria illness. One possible public health strategy, known as Intermittent Preventive Treatment in children (IPTc), is to treat all children for malaria at regular intervals during the transmission season, regardless of whether they are infected or not.

OBJECTIVES

To evaluate the effects of IPTc to prevent malaria in preschool children living in endemic areas with seasonal malaria transmission.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register (July 2011), CENTRAL (The Cochrane Library 2011, Issue 6), MEDLINE (1966 to July 2011), EMBASE (1974 to July 2011), LILACS (1982 to July 2011), mRCT (July 2011), and reference lists of identified trials. We also contacted researchers working in the field for unpublished and ongoing trials.

SELECTION CRITERIA

Individually randomized and cluster-randomized controlled trials of full therapeutic dose of antimalarial or antimalarial drug combinations given at regular intervals compared with placebo or no preventive treatment in children aged six years or less living in an area with seasonal malaria transmission.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed eligibility, extracted data and assessed the risk of bias in the trials. Data were meta-analysed and measures of effects (ie rate ratio, risk ratio and mean difference) are presented with 95% confidence intervals (CIs). The quality of evidence was assessed using the GRADE methods.

MAIN RESULTS

Seven trials (12,589 participants), including one cluster-randomized trial, met the inclusion criteria. All were conducted in West Africa, and six of seven trials were restricted to children aged less than 5 years.IPTc prevents approximately three quarters of all clinical malaria episodes (rate ratio 0.26; 95% CI 0.17 to 0.38; 9321 participants, six trials, high quality evidence), and a similar proportion of severe malaria episodes (rate ratio 0.27, 95% CI 0.10 to 0.76; 5964 participants, two trials, high quality evidence). These effects remain present even where insecticide treated net (ITN) usage is high (two trials, 5964 participants, high quality evidence).IPTc probably produces a small reduction in all-cause mortality consistent with the effect on severe malaria, but the trials were underpowered to reach statistical significance (risk ratio 0.66, 95% CI 0.31 to 1.39, moderate quality evidence).The effect on anaemia varied between studies, but the risk of moderately severe anaemia is probably lower with IPTc (risk ratio 0.71, 95% CI 0.52 to 0.98; 8805 participants, five trials, moderate quality evidence).Serious drug-related adverse events, if they occur, are probably rare, with none reported in the six trials (9533 participants, six trials, moderate quality evidence). Amodiaquine plus sulphadoxine-pyrimethamine is the most studied drug combination for seasonal chemoprevention. Although effective, it causes increased vomiting in this age-group (risk ratio 2.78, 95% CI 2.31 to 3.35; two trials, 3544 participants, high quality evidence).When antimalarial IPTc was stopped, no rebound increase in malaria was observed in the three trials which continued follow-up for one season after IPTc.

AUTHORS' CONCLUSIONS

In areas with seasonal malaria transmission, giving antimalarial drugs to preschool children (age < 6 years) as IPTc during the malaria transmission season markedly reduces episodes of clinical malaria, including severe malaria. This benefit occurs even in areas where insecticide treated net usage is high.

Chemoprophylaxis and intermittent treatment for preventing malaria in children

BACKGROUND

Malaria causes repeated illness in children living in endemic areas. Policies of giving antimalarial drugs at regular intervals (prophylaxis or intermittent treatment) are being considered for preschool children.

OBJECTIVES

To evaluate prophylaxis and intermittent treatment with antimalarial drugs to prevent malaria in young children living in malaria-endemic areas.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register (August 2007), CENTRAL (The Cochrane Library 2007, Issue 3), MEDLINE (1966 to August 2007), EMBASE (1974 to August 2007), LILACS (1982 to August 2007), mRCT (February 2007), and reference lists of identified trials. We also contacted researchers.

SELECTION CRITERIA

Individually randomized and cluster-randomized controlled trials comparing antimalarial drugs given at regular intervals (prophylaxis or intermittent treatment) with placebo or no drug in children aged one month to six years or less living in a malaria-endemic area.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed methodological quality. We used relative risk (RR) or weighted mean difference with 95% confidence intervals (CI) for meta-analyses. Where we detected heterogeneity and considered it appropriate to combine the trials, we used the random-effects model (REM).

MAIN RESULTS

Twenty-one trials (19,394 participants), including six cluster-randomized trials, met the inclusion criteria. Prophylaxis or intermittent treatment with antimalarial drugs resulted in fewer clinical malaria episodes (RR 0.53, 95% CI 0.38 to 0.74, REM; 7037 participants, 10 trials), less severe anaemia (RR 0.70, 95% CI 0.52 to 0.94, REM; 5445 participants, 9 trials), and fewer hospital admissions for any cause (RR 0.64, 95% CI 0.49 to 0.82; 3722 participants, 5 trials). We did not detect a difference in the number of deaths from any cause (RR 0.90, 95% CI 0.65 to 1.23; 7369 participants, 10 trials), but the CI do not exclude a potentially important difference. One trial reported three serious adverse events with no statistically significant difference between study groups (1070 participants). Eight trials measured morbidity and mortality six months to two years after stopping regular antimalarial drugs; overall, there was no statistically significant difference, but participant numbers were small.

AUTHORS' CONCLUSIONS

Prophylaxis and intermittent treatment with antimalarial drugs reduce clinical malaria and severe anaemia in preschool children.

Chemoprophylaxis and intermittent treatment for preventing malaria in children

BACKGROUND

Malaria causes repeated illness in children living in endemic areas. Policies of giving antimalarial drugs at regular intervals (prophylaxis or intermittent treatment) are being considered for preschool children.

OBJECTIVES

To evaluate chemoprophylaxis and intermittent treatment with antimalarial drugs to prevent malaria in young children living in malaria endemic areas.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register (April 2005), CENTRAL (The Cochrane Library Issue 1, 2005), MEDLINE (1966 to April 2005), EMBASE (1974 to April 2005), LILACS (1982 to April 2005), and reference lists of identified trials. We also contacted researchers.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials comparing antimalarial drugs given at regular intervals (prophylaxis or intermittent treatment) with placebo or no drug in children aged one month to six years or less living in an area where malaria is endemic.

DATA COLLECTION AND ANALYSIS

We independently extracted data and assessed methodological quality. We used relative risk (RR) or weighted mean difference with 95% confidence intervals (CI) for meta-analyses. Where we detected heterogeneity and considered it appropriate to combine the trials, we used the random-effects model (REM).

MAIN RESULTS

Nineteen trials (14,393 participants) met the inclusion criteria. Children receiving antimalarial drugs as prophylaxis or intermittent treatment had fewer clinical malaria episodes (RR 0.52, 95% CI 0.35 to 0.77, REM; 4051 participants, 8 trials), and severe anaemia was less common (RR 0.54, 95% CI 0.42 to 0.68; 2727 participants, 8 trials). We did not detect a difference in the number of deaths from any cause (RR 0.82, 95% CI 0.65 to 1.04; 7929 participants, 9 trials), but the confidence intervals do not exclude a potentially important difference. None of the trials reported serious adverse events. Three trials measured morbidity and mortality six months to two years after stopping regular antimalarial drugs; overall, there was no statistically significant difference, but participant numbers were small.

AUTHORS' CONCLUSIONS

Prophylaxis and intermittent treatment with antimalarial drugs reduce clinical malaria and severe anaemia in preschool children. There is insufficient evidence to detect an effect on mortality.

Chlorproguanil-dapsone for treating uncomplicated malaria

BACKGROUND

In Africa, malaria is often resistant to chloroquine and sulfadoxine-pyrimethamine. Chlorproguanil-dapsone is a potential alternative.

OBJECTIVES

To compare chlorproguanil-dapsone with other antimalarial drugs for treating uncomplicated falciparum malaria.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register (May 2004), CENTRAL (The Cochrane Library Issue 2, 2004), MEDLINE (1966 to May 2004), EMBASE (1988 to May 2004), LILACS (May 2004), Biosis Previews (1985 to May 2004), conference proceedings, and reference lists, and contacted researchers working in this field.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials comparing chlorproguanil-dapsone to other antimalarial drugs.

DATA COLLECTION AND ANALYSIS

Two reviewers independently applied the inclusion criteria, extracted data, and assessed methodological quality. We calculated the relative risk (RR) for dichotomous data and weighted mean difference for continuous data, and presented them with 95% confidence intervals (CI).

MAIN RESULTS

Six trials (n = 3352) met the inclusion criteria. Chlorproguanil-dapsone (with 1.2 mg chlorproguanil) as a single dose had fewer treatment failures than chloroquine (1 trial), but more treatment failures and people with parasitaemia at day 28 than sulfadoxine-pyrimethamine (3 trials). Two trials compared the three-dose chlorproguanil-dapsone (with 2 mg chlorproguanil) regimen with sulfadoxine-pyrimethamine in new attendees. There were fewer treatment failures with chlorproguanil-dapsone by day 7 (RR 0.30, CI 0.19 to 0.49; n = 827, 1 trial) and day 14 (RR 0.36, CI 0.24 to 0.53; n = 1709, 1 trial). Neither trial reported total failures by day 28. A further trial was carried out in participants selected because they had previously failed sulfadoxine-pyrimethamine. Adverse event reporting was inconsistent between trials, but chlorproguanil-dapsone was associated with more adverse events leading to discontinuation of treatment compared with sulfadoxine-pyrimethamine (RR 4.54, CI 1.74 to 11.82; n = 829, 1 trial). It was also associated with more red blood cell disorders (RR 2.86, CI 1.33 to 6.13; n = 1850, 1 trial).

REVIEWERS' CONCLUSIONS

There are insufficient data about the effects of the current standard chlorproguanil-dapsone regimen (three-dose, 2 mg chlorproguanil). Randomized controlled trials that follow up to day 28, record adverse events, and use an intention-to-treat analysis are required to inform any policy decisions.