Safety Signal Generation for Sudden Sensorineural Hearing Loss Following Messenger RNA COVID-19 Vaccination: Postmarketing Surveillance Using the French Pharmacovigilance Spontaneous Reporting Database.

BACKGROUND: The World Health Organization recently described sudden sensorineural hearing loss (SSNHL) as a possible adverse effect of COVID-19 vaccines. Recent discordant pharmacoepidemiologic studies invite robust clinical investigations of SSNHL after COVID-19 messenger RNA (mRNA) vaccines. This postmarketing surveillance study, overseen by French public health authorities, is the first to clinically document postvaccination SSNHL and examine the role of potential risk factors. OBJECTIVE: This nationwide study aimed to assess the relationship between SSNHL and exposure to mRNA COVID-19 vaccines and estimate the reporting rate (Rr) of SSNHL after mRNA vaccination per 1 million doses (primary outcome). METHODS: We performed a retrospective review of all suspected cases of SSNHL after mRNA COVID-19 vaccination spontaneously reported in France between January 2021 and February 2022 based on a comprehensive medical evaluation, including the evaluation of patient medical history, side and range of hearing loss, and hearing recovery outcomes after a minimum period of 3 months. The quantification of hearing loss and assessment of hearing recovery outcomes were performed according to a grading system modified from the Siegel criteria. A cutoff of 21 days was used for the delay onset of SSNHL. The primary outcome was estimated using the total number of doses of each vaccine administered during the study period in France as the denominator. RESULTS: From 400 extracted cases for tozinameran and elasomeran, 345 (86.3%) spontaneous reports were selected. After reviewing complementary data, 49.6% (171/345) of documented cases of SSNHL were identified. Of these, 83% (142/171) of SSNHL cases occurred after tozinameran vaccination: Rr=1.45/1,000,000 injections; no difference for the rank of injections; complete recovery in 22.5% (32/142) of cases; median delay onset before day 21=4 days (median age 51, IQR 13-83 years); and no effects of sex. A total of 16.9% (29/171) of SSNHL cases occurred after elasomeran vaccination: Rr=1.67/1,000,000 injections; rank effect in favor of the first injection (P=.03); complete recovery in 24% (7/29) of cases; median delay onset before day 21=8 days (median age 47, IQR 33-81 years); and no effects of sex. Autoimmune, cardiovascular, or audiovestibular risk factors were present in approximately 29.8% (51/171) of the cases. SSNHL was more often unilateral than bilateral for both mRNA vaccines (P<.001 for tozinameran; P<.003 for elasomeran). There were 13.5% (23/142) of cases of profound hearing loss, among which 74% (17/23) did not recover a serviceable ear. A positive rechallenge was documented for 8 cases. CONCLUSIONS: SSNHL after COVID-19 mRNA vaccines are very rare adverse events that do not call into question the benefits of mRNA vaccines but deserve to be known given the potentially disabling impact of sudden deafness. Therefore, it is essential to properly characterize postinjection SSNHL, especially in the case of a positive rechallenge, to provide appropriate individualized recommendations.

Distribution of non-synonymous Vkorc1 mutations in roof rats (Rattus rattus) in France and in Spain - consequences for management.

Rodent control is mainly done using anticoagulant rodenticides leading to the death of rodents through internal bleeding by targeting the VKORC1 protein. However, mutations in VKORC1 can lead to resistance to anticoagulant rodenticides that can cause treatment failure in the field. This study provides the first insight into the distribution, frequency and characterization of Vkorc1 mutations in roof rats (Rattus rattus) in France and in three administrative areas of Spain. The roof rat is present in France while it was thought to have almost disappeared with the expansion of the brown rat. Nevertheless, it has been found mainly in maritime areas. 151 roof rats out of 219 tested presented at least one missense mutation in the coding sequences of Vkorc1 gene (i.e. 69.0% of the rat). Nine Vkorc1 genotypes were detected (Y25F, A26P, R40G, S57F, W59C, W59R, H68N, Y25F/K152T and Y25F/W59R. Biochemical characterization of the consequences of these different genotypes proved that these various genotypes did not induce severe resistance to anticoagulant rodenticides. Even if many mutations of the Vkorc1 gene are present in roof rat populations in France, their management may be based in a first approach, considering the low levels of resistance induced, on the use of first-generation anticoagulants less dangerous for wildlife. The use of second-generation may be considered when treatment failure is observed or when bait consumption is limited.

Drug-induced retroperitoneal fibrosis: a case/non-case study in the French PharmacoVigilance Database.

OBJECTIVES: The potential role of drugs in the onset of retroperitoneal fibrosis (RPF) is poorly understood. The aim of this study was to identify drugs that may cause RPF. METHODS: The authors used case/non-case method in the French PharmacoVigilance Database (FPVD). RESULTS: Among the 722992 reports recorded, 73 cases of RPF were identified. 67% were men and the median age was 60 years (range 26-87). In these 73 cases, 176 drugs were 'suspect.' Derivatives of ergot alkaloids (DEA) presented the most significant association with RPF. To a lesser extent, significant associations were found with many drugs used in cardiology, e.g. beta-blockers, platelet antiaggregant, statins, and antihypertensive drugs, drugs used in neuropsychiatry, e.g. hypnotics, antiepileptic drugs, anxiolytics, antipsychotics, and antidepressants, and with other pharmacological classes, e.g. TNF-alpha antagonists. CONCLUSION: This study confirmed an association between RPF and derivatives of ergot alkaloids. These data represent a pharmacovigilance signal despite the limits of non/non-case method (underreporting, confounding factors, etc.). Indeed, a significant signal was found with drugs less known (TNF-α antagonists) or not known (some hypnotics, antiepileptic drugs, antipsychotics, anxiolytics, and antidepressants) to induce such an adverse drug reaction (ADR). Finally, these data could contribute to realize prospective studies to confirm these signals.

Cis-bromadiolone diastereoisomer is not involved in bromadiolone Red Kite (Milvus milvus) poisoning.

Anticoagulant rodenticides (ARs) are widely used pesticides to control rodent populations. Bromadiolone, a second generation anticoagulant rodenticide (SGARs), is authorized in France to control the population of water voles (Arvicola scherman). The persistence of SGARs in rodents is responsible for secondary exposure or poisoning of predators and scavengers, and is of ecological concern for the conservation of endangered species. Commercial formulations are a mixture of two diastereoisomers of bromadiolone: 70-90% is trans-bromadiolone and 10-30% is cis-bromadiolone. Both diastereoisomers have been shown to inhibit coagulation function with the same potency. On the other hand, cis-bromadiolone has been shown to be less tissue-persistent than trans-bromadiolone in rats. This difference led to residue levels in rats with substantially weakened proportion in cis-bromadiolone compared to the composition of baits. In this study, a multi-residue LC-MS/MS method for the quantification of the diastereoisomers of SGARs was used to investigate their proportions in field samples of predators. In 2011, 28 red kites (Milvus milvus) were found dead within a few months of bromadiolone application in grassland to control water vole outbreaks. In this study, we report the concentrations of the two diastereoisomers of bromadiolone measured in the livers of thirteen red kites. Exposure to bromadiolone was apparent in all the kites with hepatic concentrations of trans-bromadiolone ranging from 390 to 870ng/g (89 to 99% of summed SGARs). However, cis-bromadiolone was not detected in 5 of 13 red kites and was present at very low concentrations (below 2.2ng/g) in 8 of 13 kites, demonstrating that cis-bromadiolone is not involved in this red kite poisoning event. The results suggest that a change of the proportions of bromadiolone diastereoisomers in baits could reduce the risk of secondary poisoning of predators, but retain primary toxicity for control rodent outbreaks.

Monitoring of antivitamin K-dependent anticoagulation in rodents - Towards an evolution of the methodology to detect resistance in rodents.

Vitamin K antagonists are used as rodenticides for pest control management. In rodents, prothrombin time is used to monitor their effect despite its limits and the emergence of many coagulation methods. The aim of this study is to explore different coagulation monitoring methods in order to propose the best method and the best parameter to monitor vitamin K antagonists effect in rodents. The coagulation function was thus monitored with global coagulation assays and specialty assays after difethialone administration in rats. Despite many parameters obtained by thromboelastometry, only clotting time and clot formation time obtained by ExTEM were modified. Their evolution was fast with doubling time respectively of 4.0h and 3.7h but their increases were delayed with a lag time higher than 8h. Conversely, prothrombin time evolution presented a lag time of only 2h, but a higher doubling time of 7.2h. The measurements of factor VII and X activities were the most sensitive assays to monitor vitamin K antagonists effect with almost no lag time and the fastest evolution. Nevertheless, factor X was shown to be the only key factor driving prothrombin time. Monitoring factor X activity enables to follow most effectively the anticoagulation status in rats after rodenticides administration.

Management of Rodent Populations by Anticoagulant Rodenticides: Toward Third-Generation Anticoagulant Rodenticides.

Second-generation anticoagulant rodenticides (SGARs) have been used since the 1980s for pest management. They are highly efficient even in warfarin-resistant rodents. Nevertheless, because of their tissue persistence, nontarget poisoning by SGARs is commonly described in wildlife. Due to this major problem, a new generation of anticoagulants must be developed to limit this risk. This study proposes a method of developing a new generation of anticoagulant rodenticides by revisiting the old SGARs based on the concept of stereochemistry. Each current SGAR is a mixture of diastereomers. Diastereomers of each compound were purified, and their biologic properties were compared by determining their ability to inhibit vitamin K epoxide reductase (VKOR) activity involved in the activation of vitamin K-dependent clotting factors and their toxicokinetic properties. Systematically, for each SGAR, both diastereomers are as effective in inhibiting VKOR activity. However, their toxicokinetic properties are very different, with one of the two diastereomers always more rapidly cleared than the other one. For all SGARs except flocoumafen, the less persistent diastereomer is always the less predominant isomer present in the current mixture. Therefore, the development of baits containing only the less persistent diastereomer would avoid the ecotoxicological risk associated with their use without decreasing their efficacy.

Core-shell LC-MS/MS method for quantification of second generation anticoagulant rodenticides diastereoisomers in rat liver in relationship with exposure of wild rats.

Second generation anticoagulant rodenticides (SGARs), pesticides used worldwide to control rodent populations, exist in two diastereoisomer chemical species because they own two stereogenic centers. A core-shell LC-MS/MS multi-residue method for comprehensive quantitative analysis of the diastereoisomers of five SGARs as well as three first generation anticoagulant rodenticide molecules has been fully validated in liver of rats according to a bioanalytical guideline. A core-shell column (superficially porous particles) has been chosen for its ability to separate the diastereomers of bromadiolone, difenacoum, brodifacoum, flocoumafen and difethialone and for its robustness to rat liver extracts. The highly selective chromatographic separation of the diastereoisomers contributes to good signal to noise ratios and then enhances the sensitivity of the method compared to the ones of fully porous columns. An elution gradient has been optimized with 10mM ammonium acetate and acetonitrile as aqueous/organic mobile phase respectively. Triple quadrupole mass detector has been used to achieve specifity and LLOQ from 0.92 to 2.2ng/g for each diastereoisomer, or first generation anticoagulant rodenticides. Then we evidenced diastereoisomeric ratios in liver of rats issued from not controlled exposure of wild rats (Rattus norvegicus) trapped in a French Parisian park through a campaign of rodent eradication. We compared them to diastereoisomeric ratios in SGARs commercial baits that contain both isomers, and showed that one of the two diastereoiomers had nearly disappeared in liver of rats. The proportions of cis-bromadiolone and trans-difenacoum were really lowered compared to the baits: 5/7 and 9/12 rats had only trans-bromadiolone and cis-difenacoum hepatic residues respectively. Liver persistence of the two diastereoisomers of bromadiolone and difenacoum was different due to differences in their pharmacokinetics in wild rats. The new core-shell LC-MS/MS method is particularly well adapted for further exploration of diastereoisomers ratios in rodent and predatory wildlife biological samples in order to evaluate ecological consequences of actual baits, to explore new formulated baits with a good balance between efficacity (ability to kill rodents) and diastereoisomers persistence, and hopefully to mitigate exposure of non-target species.

Development of an Ecofriendly Anticoagulant Rodenticide Based on the Stereochemistry of Difenacoum.

Difenacoum, an antivitamin K anticoagulant, has been widely used as rodenticide to manage populations of rodents. Difenacoum belongs to the second generation of anticoagulant, and, as all the molecules belonging to the second generation of anticoagulant, difenacoum is often involved in primary poisonings of domestic animals and secondary poisonings of wildlife by feeding contaminated rodents. To develop a new and ecofriendly difenacoum, we explored in this study the differences in properties between diastereomers of difenacoum. Indeed, the currently commercial difenacoum is a mixture of 57% of cis-isomers and 43% of trans-isomers. Cis- and trans-isomers were thus purified on a C18 column, and their respective pharmacokinetic properties and their efficiency to inhibit the coagulation of rodents were explored. Tissue persistence of trans-isomers was shown to be shorter than that of cis-isomers with a half-life fivefold shorter. Efficiency to inhibit the vitamin K epoxide reductase activity involved in the coagulation process was shown to be similar between cis- and trans-isomers. The use of trans-isomers of difenacoum allowed to drastically reduce difenacoum residues in liver and other tissues of rodents when the rodent is moribund. Therefore, secondary poisonings of wildlife should be decreased by the use of difenacoum largely enriched in trans-isomers.