An Observational Study to Find the Association of Viral Load, NS1 Antigen, IgG Antibody, and Other Laboratory Parameters With the Outcome of Dengue Patients in Eastern India.

Background Dengue, the mosquito-borne febrile disease caused by the dengue virus, has become one of the major concerns of public health. It may present with only fever, or there may be a hemorrhagic manifestation or septic shock. As there is no specific treatment for dengue, early detection of the disease, assessment of progression, and prediction of outcome by studying the laboratory markers will help guide the management of cases and lower morbidity and mortality. Methodology This clinico-observational study was conducted at the Department of Microbiology in a tertiary care hospital in Kolkata, India, from February 2020 to August 2022 to determine the outcome of dengue patients in correlation with viral load, NS1 antigen, IgM and IgG antibodies, ferritin level, platelet count, and other laboratory parameters. Results Out of 316 samples from fever patients, 103 (32.5%) were NS1 antigen reactive. We followed up the dengue patients (n = 103) for 15 days and divided them into three groups according to their duration of symptoms (group A suffered for ≤5 days, group B for 5 to 10 days, and group C for >10 days) and per the WHO classification of disease severity, namely dengue without warning signs (DOS), dengue with warning signs (DWS), and severe dengue (SD). Based on severity, 65 (63.1%) patients had DOS, whereas 31 (30.09%) patients had DWS, and seven (6.79%) patients had SD. Secondary infection was present in 83.33% of patients in group C, 71% of DWS cases, and 57% of SD cases, which positively correlates with liver enzymes, viral load (mean value 102195 in secondary infection vs. 1195 copies/10 µl in primary infection), and negatively correlates with platelet counts (mean value 60,213 in secondary infection vs. 1,25,516 in primary infection). Patients in group C had higher liver enzymes, a lower platelet count, and a higher initial viral load than groups A and B. Similarly, SD cases had a higher ferritin level (9215 ug/l), a lower platelet count (mean value 23,250), and a higher initial viral load (mean value 2,74,257 copies/10 µl). An increase in hematocrit value considering the peak value and its baseline value is an important marker for disease severity rather than its absolute value. Conclusion Poor outcome of dengue infection, i.e., an increase in the duration of symptoms and disease severity depends on concurrent associations between high serum ferritin, increased hematocrit level, thrombocytopenia, secondary infection, increasing liver enzymes, and increased initial viral load.