Fig. 3: How fever symptoms of COVID-19 and malaria may influence diagnoses.

a, A systematic review of the literature showing how the percentage of COVID-19 cases with fever varies with respect to age. Points show published estimates colored according to the cohort in which they were observed: patients admitted to hospital (red), patients admitted to ICUs (green), contacts of known cases (blue) or a mixed cohort (purple). A summary of all data including precise estimates and sample sizes for each study are provided in Supplementary Table 13. The solid line shows best-fit logistic regression line fit to all groups, and the shaded region indicates 95% confidence interval estimates in the mean. Vertical colored lines show the interquartile range for the proportion of fevers (when available) whereas the horizontal colored lines show the range of ages reported in each cohort. b, Left column figures show estimates of how the proportion of malaria fevers relative to COVID-19 fevers (that is, proportion of fevers due to malaria divided by malaria + COVID-19 fevers) varies over time; the right column shows the proportion of COVID-19 cases co-infected with asymptomatic malaria. The top row shows predictions for seasonal Mali; the bottom row shows the more perennial Uganda. In all panels in b, black lines indicate prevalence of malaria (as detected by microscopy) and dashed lines show COVID-19 prevalence; colored lines indicate age of group in years, 0–5 (red), 5–15 (green) or >15 (blue) years of age (scaling COVID-19 fevers by age using the regression line presented in a). c, Country-level mean estimates of the fraction of fevers due to malaria compared with those due to malaria and/or COVID-19 in children aged <5 years in July 2020. Maps were prepared using GADM v.3.6 (https://gadm.org).