Impact of current malaria infection and previous malaria exposure on the clinical profiles and outcome of COVID-19 in a high malaria transmission setting

Our co-infection study found that low previous malaria exposure was associated with severe or critical COVID-19 and adverse outcomes in a high burden malaria setting.

Background
Our understanding of the potential impact of SARS-CoV-2 and malaria co-infection on host susceptibility and pathogenesis remains unclear. We determined the prevalence of malaria and describe the consequences of SARS-CoV-2 and malaria co-infection in a high burden malaria setting. 

Methods
This was a prospective cohort study of hospitalised COVID-19 patients in Uganda. Malaria diagnosis was done using rapid diagnostic tests, microcopy and molecular methods. Previous P. falciparum exposure was assessed using serologic responses to a panel of P. falciparum antigens using a multiplex bead assay. Additional evaluations included complete blood count, markers of inflammation and serum biochemistries. 

Findings
Of 597 PCR confirmed COVID-19 cases enrolled between 16th April and 30th October 2020, 500 (84.1 percent) were male and median age (1QR) was 36 (28–47) years. Overall prevalence of P. falciparum infection was 11.7 percent (70/597, 95 percent CI 9.4 to 14.6), with highest prevalence in the 0–20 years (21.7 percent, 5/23, 95 percent CI 8.7–44.8) and > 60 years (19.6 percent, 9/46, 95 percent CI 10.2–34.1) age groups. Confusion [5.7 percent (4/70) vs. 1.5 percent, (8/527), p=0.04] and vomiting [5.7 percent (5/70) vs.1.0 percent, 5/527), p=0.007] were more frequent among patients with P. falciparum infection. Patients with low previous P. falciparum exposure had a higher frequency of severe/critical COVID-19 cases (30.2 percent, 16/53, p=0.001), a higher burden of comorbidities [hypertension (30.2 percent, 16/53, p=0.02) and diabetes (22.6 percent, 12/53, p=0.003)] and more deaths (3.8 percent, 2/53, p=0.01). Among patients with no comorbidities, those with low previous exposure still had a higher proportion of severe/critical COVID-19 cases (18.2 percent, 6/53 vs. 2.0 percent, 1/56, p=0.01) compared to those with high exposure.

Interpretation
Prevalence of P. falciparum infection among COVID-19 patients was relatively high. Though COVID-19 patients with P. falciparum infection had a higher frequency of confusion and vomiting, co-infection with malaria did not seem deleterious. Low previous malaria exposure was associated with severe/critical COVID-19 and adverse outcomes.

Published in The Lancet Microbe

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Country: Uganda

Keywords: Research | COVID-19 | Malaria | Case management | Treatment | Vaccines | SDGs