COVID-19 infection and its association with severe malaria & dengue: an epidemiological study from Southern India.

Background: Post-Coronavirus Disease-19 (COVID-19) sequelae involve complex biological processes that can alter the progression and clinical outcome of other infectious diseases. However, there is no documented information on the influence of COVID-19 on the development of severe malaria and dengue. Hence, this study was conducted to determine the association between malaria & dengue and previous COVID-19 infection among the adult population of Mangalore Taluk and to describe the socio-demographic and clinical correlates of malaria & dengue.

Methods: This case-control study was conducted among 293 participants who were positive for either malaria or dengue from November 2022 to August 2024. Data were collected using a proforma which contained sections on demographic details, clinical profile and comorbidities, history of COVID-19 infection and COVID-19 vaccination status. The participants were categorised into having severe disease and mild to moderate disease based on operational definitions. The data were analysed using the Statistical Package for Social Sciences (SPSS) version 29. Chi-square test was done, and a p-value less than 0.05 was considered statistically significant. Binary Logistic Regression analyses were used and odds ratios were estimated.

Results: A total of 293 participants were included in the study with a mean age of 36.7 (SD:14.8) years. Among them, 23.9% (n = 70) had malaria and 76.1% (n = 223) had dengue. Out of those who had malaria, 30% (n = 21) developed severe illness, whereas among those who had dengue 35.8% (n = 80) developed severe dengue. Overall, 58.4% (n = 171) were in the age group of > 30 years. In total, 98.1% (n = 52) of the participants with dengue fever with a history of COVID-19 infection developed severe dengue, (aOR:55.93 (95% CI:7.17-435.92) p < 0.001) compared to those without. Similarly, 85.7% (n = 12) of the participants with a history of COVID-19 infection developed severe malaria (aOR: 263.7 (95% CI: 34.9-1987.4) p < 0.001) compared to those and these differences were found to be statistically significant. In addition, those participants belonging to lower socio-economic classes had higher chances of developing severe dengue than those belonging to the upper socio-economic class (p < 0.001*).

Conclusion: Those with a prior history of COVID-19 infection had higher chances of developing severe malaria and dengue than those without a history of COVID-19 infection.