Response to the Letter to the Editor: Effectiveness of Eupatorium perfoliatum 30C in Preventing Dengue Fever: A Critical Appraisal

Effectiveness of Eupatorium perfoliatum 30C in Preventing Dengue Fever: A Critical Appraisal

We appreciate the constructive feedback[1] on our study, “Effectiveness of Eupatorium perfoliatum 30C in Preventing Dengue Fever—A Prospective, Community-Based, Open Label, Parallel Cohort Study in Delhi, India”.[2] The comments highlighted the key points of our research, enabling us to elaborate the significance of our results within the broader public health context.

We acknowledge the limitations of an open-label, nonrandomized design and also recognize that a randomized controlled trial (RCT) with placebo control and blinding is the gold standard for establishing causality of intervention.[3] Conducting an RCT was considered; however, given the scope and scale of our study, as well as time constraints, cost restrictions or ethical considerations, an open-label, parallel cohort design was chosen as a pragmatic approach to generate preliminary evidence and evaluate the effectiveness of Eupatorium perfoliatum (EP) 30C in a real-world, high-risk setting, providing also the flexibility to outreach a larger population during the seasonal dengue outbreak. Additionally, for assessing intervention effectiveness, recommendations support the use of observational studies, specifically those utilizing a parallel cohort design.[4] Well-designed clinical observational studies have demonstrated outcomes comparable to those of RCTs.[5] Although we were unable to employ blinding, our adherence to stringent cohort design standards and carefully designed study methods helped to minimize biases.[6] However, in our paper we discussed the limitations of the study, referring to the need for RCTs to validate our findings.[2]

In this study, we followed the case definitions notified by the National Vector-Borne Disease Control Program, Government of India,[7] for surveillance of dengue, to classify the suspected, probable, and laboratory-confirmed dengue, thereby standardizing our diagnostic approach. The concern regarding the reliability of self-reported data and the potential inaccuracy in diagnosing dengue is valid. This risk was minimised by active surveillance, sample collection of febrile cases for laboratory tests, and monitoring by regular home visits by our health workers and field doctors.

Our findings, which show a significant protective effect against both probable and laboratory-confirmed dengue, offer preliminary evidence supporting homeopathic interventions as a complementary public health strategy. The results of our study, despite being statistically significant, may not fully represent the broader epidemiological impact, but they do demonstrate a potential preventive measure that may reduce dengue incidence.

We are hopeful that use of homeopathic interventions, such as EP 30C, can contribute meaningfully to dengue prevention initiatives. The need to incorporate alternative approaches alongside conventional ones is essential to balance evidence-based practices with practical, accessible solutions for vulnerable populations.

We acknowledge that to fully translate these preliminary findings to a public health program, further investigations are required in the form of basic research to ascertain the mechanisms of action of EP 30C. Laboratory and pre-clinical studies exploring immune modulation and antiviral activity will be crucial for scientific validity of a protective effect. Although in this study the identified clusters for the intervention and control arms were from the same sociopsychological background, we also support the suggestion to evaluate psychosocial factors that influence participants' compliance and health-seeking behavior, as understanding these factors can provide a more holistic view of EP 30C's potential impact.

We thank the authors of the letter for their valuable comments and for fostering a critical discussion on the use of traditional homeopathic methods in epidemic settings. We envision a future in which homeopathic and conventional approaches coexist within integrated public health frameworks. We look forward to further rigorous trials along with basic research to consolidate and expand upon our findings.

Publication History

Received: 30 November 2024

Accepted: 03 December 2024

Article published online:
25 February 2025

• References

• 1 Daungsupawong H, Wiwanitkit V. Effectiveness of Eupatorium perfoliatum 30C in preventing dengue fever: a critical appraisal. Homeopathy. 2025 (e-pub ahead of print)
• 2 Nayak D, Kaur L, Bhalerao R. et al. Effectiveness of Eupatorium perfoliatum 30C in preventing dengue fever—a prospective, community-based, open label, parallel cohort study in Delhi, India. Homeopathy. 2024 (e-pub ahead of print).
• 3 Misra S. Randomized double blind placebo control studies, the “Gold Standard” in intervention based studies. Indian J Sex Transm Dis AIDS 2012; 33: 131-134
• 4 World Health Organization. Cohort study to measure COVID-19 vaccine effectiveness among healthworkers. Accessed September 11, 2023 at: https://www.who.int/publications/i/item/WHO-EURO2021-2141-41896-57484
• 5 Song JW, Chung KC. Observational studies: cohort and case-control studies. Plast Reconstr Surg 2010; 126: 2234-2242
• 6 Farjat AE, Virdone S, Thomas LE. et al. The importance of the design of observational studies in comparative effectiveness research: lessons from the GARFIELD-AF and ORBIT-AF registries. Am Heart J 2021; 243: 110-121
• 7 National Center for Vector Borne Diseases Control. National Guidelines for Clinical Management of Dengue Fever. Accessed September 29, 2023 at: https://ncvbdc.mohfw.gov.in/WriteReadData/l892s/Dengue-National-Guidelines-2014.pdf