Patients with sickle cell anemia (SCA) may be protected from severe disease with malaria. However, severe complications, such as severe drops in hemoglobin, may occur in SCA patients with concomitant low-density malarial infection.
Sickle cell anemia (SCA) has historically been linked to high levels of childhood mortality in Africa, with malaria playing a significant role. A report recently published in The Lancet explored the relationship between SCA and malaria in detail.
The TRACT trial enrolled 3944 children with severe anemia aged 2 months to 12 years in four African hospitals. This study is a secondary analysis of the TRACT trial data of Uganda, where the birth prevalence of SCA is approximately 1% and malaria transmission is high.
Clinical symptoms similar to malaria can develop in children with SCA who do not have malaria. The determination of the malaria parasite burden in the blood can help doctors discern between true severe malaria and other causes of severe illness in children incidentally carrying malaria parasites.
The results showed that 30% of the Ugandan children who took part in this study had SCA. The total parasite burden within an individual was significantly lower in children with SCA (33%) than in healthy children without SCA (78%). The researchers also found no evidence that people with SCA died more often than people without SCA by day 28.
Data from the current and other recent studies are consistent with a model that was proposed earlier. When there is high-density malaria, SCA gives some natural resistance and protects against organ failure. Another possible reason for resistance is that these parasites are less dangerous by nature. However, the study also revealed that low-density malaria infections can cause rapid and potentially fatal falls in haemoglobin. More research is needed to determine the most important mechanisms of resistance.
Source
Uyoga, S., Olupot-Olupot, P., Connon, R., Kiguli, S., Opoka, R. O., Alaroker, F., . . . Williams, T. N. (2022). Sickle cell anaemia and severe Plasmodium falciparum malaria: a secondary analysis of the Transfusion and Treatment of African Children Trial (TRACT). Lancet Child Adolesc Health, 6(9), 606-613. doi:10.1016/s2352-4642(22)00153-5
