METHODOLOGY: During this study, enzyme activity was measured in 53/59 (89.8%) hospital-diagnosed G6PD-deficient neonates (34 Malays, 12 Chinese, and seven other ethnic groups) born consecutively in the Kuala Lumpur Maternity Hospital. All neonates, except one, were males.

RESULTS: The mean level of enzyme activity of the 52 males G6PD-deficient neonates (0.47 iu/g Hb, 95% confidence intervals: 0.37, 0.57) was less than 10% of that of normal Malaysian male neonates. The enzyme activity of the only female G6PD-deficient infant, at 1.11 iu/g Hb, was 12.5% of the mean G6PD enzyme activity of normal females.

METHODS: A systematic review identified P. vivax efficacy studies of chloroquine with or without primaquine published between January 2000 and March 2017. Individual patient data were pooled using standardised methodology, and the haematological response versus time was quantified using a multivariable linear mixed effects model with non-linear terms for time. Mean differences in haemoglobin between treatment groups at day of nadir and day 42 were estimated from this model.

RESULTS: In total, 3421 patients from 29 studies were included: 1692 (49.5%) with normal G6PD status, 1701 (49.7%) with unknown status and 28 (0.8%) deficient or borderline individuals. Of 1975 patients treated with chloroquine alone, the mean haemoglobin fell from 12.22 g/dL [95% CI 11.93, 12.50] on day 0 to a nadir of 11.64 g/dL [11.36, 11.93] on day 2, before rising to 12.88 g/dL [12.60, 13.17] on day 42. In comparison to chloroquine alone, the mean haemoglobin in 1446 patients treated with chloroquine plus primaquine was - 0.13 g/dL [- 0.27, 0.01] lower at day of nadir (p = 0.072), but 0.49 g/dL [0.28, 0.69] higher by day 42 (p  25% to  5 g/dL.

CONCLUSIONS: Primaquine has the potential to reduce malaria-related anaemia at day 42 and beyond by preventing recurrent parasitaemia. Its widespread implementation will require accurate diagnosis of G6PD deficiency to reduce the risk of drug-induced haemolysis in vulnerable individuals.