Saw-scaled viper venom antiserum solution for injection 10ml ampoules

BackgroundThe World Health Organization's strategy to halve snakebite mortality and morbidity by 2030 includes an emphasis on a risk-benefit process assessing the preclinical efficacy of antivenoms manufactured for sub-Saharan Africa. To assist this process, we systematically collected, standardised and analysed all publicly available data on the preclinical efficacy of antivenoms designed for sub-Saharan Africa.Methodology/principal findingsUsing a systematic search of publication databases, we focused on publicly available preclinical reports of the efficacy of 16 antivenom products available in sub Saharan Africa. Publications since 1999 reporting the industry standard intravenous pre-incubation method of murine in vivo neutralisation of venom lethality (median effective dose [ED50]) were included. Eighteen publications met the criteria. To permit comparison of the several different reported ED50 values, it was necessary to standardise these to microlitre of antivenom resulting in 50% survival of mice challenged per milligram of venom (μl/mg). We were unable to identify publicly available preclinical data on four antivenoms, whilst data for six polyspecific antivenoms were restricted to a small number of venoms. Only four antivenoms were tested against a wide range of venoms. Examination of these studies for the reporting of key metrics required for interpreting antivenom ED50s were highly variable, as evidenced by eight different units being used for the described ED50 values.Conclusions/significanceThere is a disturbing lack of (i) preclinical efficacy testing of antivenom for sub Saharan Africa, (ii) publicly available reports and (iii) independent scrutiny of this medically important data. Where reports do exist, the methods and metrics used are highly variable. This prevents comprehensive meta-analysis of antivenom preclinical efficacy, and severely reduces the utility of antivenom ED50 results in the decision making of physicians treating patients and of national and international health agencies. Here, we propose the use of a standardised result reporting checklist to resolve this issue. Implementation of these straightforward steps will deliver uniform evaluation of products across laboratories, facilitate meta-analyses, and contribute vital information for designing the clinical trials needed to achieve the WHO target of halving snakebite morbidity and mortality by 2030.

Abstract licence: CC BY

IntroductionIndia, with nearly 60 venomous snake species, has just one commercially available antivenom, the Indian polyvalent antivenom (IPAV). The hump-nosed pit viper (Hypnale hypnale), an indigenous venomous snake, causes considerable morbidity and at time mortality for which we have no commercially available antivenom. However, most clinicians rely purely on the clinical syndromes and end up using the available IPAV for H. hypnale envenomation.MethodsBetween April 2017 and December 2022, we reviewed 41 cases of H. hypnale envenomation, comparing clinical and laboratory profiles of patients who received IPAV with those who did not.ResultsLocal signs of envenomation were seen in 39 (95.12%) cases, with the most common being edema or swelling at the bite site. Eight (19.5%) patients developed coagulopathy, and two developed renal failure during their hospital stay. Among the 39 envenomated individuals, 13 received polyvalent snake antivenom. Over half of those receiving antivenom had hypersensitivity reactions. Patients who received antisnake venom (ASV) had increased intensive care unit stay, duration of hospitalization, and hospital expenses as compared to patients who did not. There was one death among the patients who received antivenom.ConclusionH. hypnale viper envenomation is associated with local and systemic signs of envenomation, with coagulopathy being a common complication. Administering the current polyvalent antivenom to victims of H. hypnale bites did not reduce the morbidities or prevent mortality; instead, it exposes them to additional risks associated with ASV administration.

Abstract licence: CC BY-NC-SA