Single-dose rifampicin chemoprophylaxis protects those who need it least and is not a cost-effective intervention

Post-exposure prophylaxis in leprosy (PEOPLE): a cluster randomised trial

BACKGROUND

Post-exposure prophylaxis (PEP) using single-dose rifampicin reduces progression from infection with Mycobacterium leprae to leprosy disease. We compared effectiveness of different administration modalities, using a higher (20 mg/kg) dose of rifampicin-single double-dose rifampicin (SDDR)-PEP.

METHODS

We did a cluster randomised study in 16 villages in Madagascar and 48 villages in Comoros. Villages were randomly assigned to four study arms and inhabitants were screened once a year for leprosy, for 4 consecutive years. All permanent residents (no age restriction) were eligible to participate and all identified patients with leprosy were treated with multidrug therapy (SDDR-PEP was provided to asymptomatic contacts aged ≥2 years). Arm 1 was the comparator arm, in which no PEP was provided. In arm 2, SDDR-PEP was provided to household contacts of patients with leprosy, whereas arm 3 extended SDDR-PEP to anyone living within 100 m. In arm 4, SDDR-PEP was offered to household contacts and to anyone living within 100 m and testing positive to anti-phenolic glycolipid-I. The main outcome was the incidence rate ratio (IRR) of leprosy between the comparator arm and each of the intervention arms. We also assessed the individual protective effect of SDDR-PEP and explored spatial associations. This trial is registered with ClinicalTrials.gov, NCT03662022, and is completed.

FINDINGS

Between Jan 11, 2019, and Jan 16, 2023, we enrolled 109 436 individuals, of whom 95 762 had evaluable follow-up data. Our primary analysis showed a non-significant reduction in leprosy incidence in arm 2 (IRR 0·95), arm 3 (IRR 0·80), and arm 4 (IRR 0·58). After controlling for baseline prevalence, the reduction in arm 3 became stronger and significant (IRR 0·56, p=0·0030). At an individual level SDDR-PEP was also protective with an IRR of 0·55 (p=0·0050). Risk of leprosy was two to four times higher for those living within 75 m of an index patient at baseline.

INTERPRETATION

SDDR-PEP appears to protect against leprosy but less than anticipated. Strong spatial associations were observed within 75 m of index patients. Targeted door-to-door screening around index patients complemented by a blanket SDDR-PEP approach will probably have a substantial effect on transmission.

FUNDING

European and Developing Countries Clinical Trials Partnership.

TRANSLATION

For the French translation of the abstract see Supplementary Materials section.

Leprosy chemoprophylaxis of household contacts: A survey of Canadian infectious disease and tropical medicine specialists

BACKGROUND

Leprosy is uncommon in Canada. However, immigration from leprosy-endemic areas has introduced the infection to a Canadian context, in which most doctors have little knowledge of the disease. Although post-exposure chemoprophylaxis (PEP) is reported to decrease leprosy transmission, no Canadian guidelines advise clinical decision making about leprosy PEP. Here, we characterize the practice patterns of Canadian infectious disease specialists with respect to leprosy PEP and screening of household contacts by yearly physical examinations.

METHODS

Canadian infectious disease specialists with known experience treating leprosy were identified using university faculty lists. An online anonymous survey was distributed. Certain questions allowed more than one response.

RESULTS

The survey response rate was 46.5% (20/43). Thirty-five percent responded that PEP is needed for household contacts, 40.0% responded that PEP is not needed for household contacts, and 25.0% did not know whether PEP is needed (multinomial test p = 0.79). Twenty-five percent responded that PEP should be given to all household contacts, 62.5% responded that PEP should be given to contacts of multibacillary cases, and 25.0% responded that PEP should be given to contacts who are genetically related to the index case. For specialists who prescribe PEP, 57.1% use rifampicin, ofloxacin (levofloxacin), and minocycline; 14.3% prescribe single-dose rifampicin; and 28.6% prescribe multiple doses of rifampicin (multinomial test p = 0.11). In addition, 68.4% recommend yearly screening of household contacts, whereas 31.6% do not (multinomial test p = 0.17).

CONCLUSION

Consensus among Canadian infectious diseases specialists is lacking regarding leprosy PEP and screening of household contacts.

Vigilance Needed in Treating Leprosy Patients in Accordance with WHO's AWaRe

BACKGROUND

Leprosy is a highly stigmatized disease that can range from a minor skin lesion to life-threatening conditions such as deformities and disability. The World Health Organization (WHO) has developed a tool called "Access, Watch, and Reserve" (AWaRe) to reduce antibiotic misuse and abuse.

AIM

The purpose of this review is to determine whether the drugs used in the leprosy treatment regimen are complied with the AWaRe programme, in order to improve the quality of hospital antibiotic use and reduce the incidence of antimicrobial resistance (AMR).

METHODS

We started by looking for antibiotics that are used in the treatment and chemoprophylaxis of leprosy, as defined by the WHO's AWaRe classification. Furthermore, we look for studies on antibiotics that showed sensitivity or less resistance after antimicrobial sensitivity testing (AST) on isolates from infected leprosy ulcers, as well as their AWaRe category.

RESULTS

There were 32 studies found, but only 5 of them met the inclusion criteria. They consisted of four cross-sectional studies and one descriptive retrospective study. A total of 19 antibiotics were identified in 5 studies, with 9 (47.4%) antibiotics in the access category, 8 (42.1%) antibiotics in the watch group, and 2 (10.5%) antibiotics in the reserve group.

CONCLUSION

As per our knowledge, this is the first study to explore antibiotics in leprosy treatment, chemoprophylaxis, and complications such as ulcer compliance with the AWaRe programme. Antimicrobial resistance is on the rise, which is a global issue that continues to pose challenges to clinical practices. This review may provide physicians with an overview of the current state of drug prescribing trends in leprosy, whether in accordance with the AWaRe classification in selecting the right drug when the use of antimicrobials is indicated and may also aid in rational drug prescribing.

Treatment and Evaluation Advances in Leprosy Neuropathy

Neuropathy and related disabilities are the major medical consequences of leprosy, which remains a global medical concern. Despite major advances in understanding the mechanisms of M. leprae entry into peripheral nerves, most aspects of the pathogenesis of leprosy neuropathy remain poorly understood. Sensory loss is characteristic of leprosy, but neuropathic pain is sometimes observed. Effective anti-microbial therapy is available, but neuropathy remains a problem especially if diagnosis and treatment are delayed. Currently there is intense interest in post-exposure prophylaxis with single-dose rifampin in endemic areas, as well as with enhanced prophylactic regimens in some situations. Some degree of nerve involvement is seen in all cases and neuritis may occur in the absence of leprosy reactions, but acute neuritis commonly accompanies both Type 1 and Type 2 leprosy reactions and may be difficult to manage. A variety of established as well as new methods for the early diagnosis and assessment of leprosy neuropathy are reviewed. Corticosteroids offer the primary treatment for neuritis and for subclinical neuropathy in leprosy, but success is limited if nerve function impairment is present at the time of diagnosis. A candidate vaccine has shown apparent benefit in preventing nerve injury in the armadillo model. The development of new therapeutics for leprosy neuropathy is greatly needed.

Neuropathies of leprosy

Neuropathies form an integral part of the symptomatology of leprosy. Neuropathies of leprosy take various forms and shapes. At one end is the cutaneous nerve involvement adjacent to the anaesthetic skin patch and the other is of symmetrical pansensory neuropathy and the devastating sensory ataxia of leprous ganglionits. Lepra reactions add to the spectrum. Hosts immunological status largely decides the clinical manifestations seen in nerves and skin. A wide array of diagnostic techniques like ultrasonography, magnetic resonance neurography, serological markers, molecular tests, skin biopsy and in selected cases, the nerve biopsy with special stains and electron microscopy are obtainable to help the clinical diagnosis. The unsuspecting clinician, lack of community awareness and limited availability of diagnostic tests are important adverse factors in the total outcome. Multi drug therapy is efficacious and corticosteroids reduce the impact of nerve damage in leprosy. The efficacy, dose and duration of corticosteroid therapy are presently inexact and other immune suppressants like azathioprine are being evaluated. Chronic disabilities and residual deficits require attention of multiple specialties. In the coming time, focus on prevention could lead to favourable results. This review will discuss the classification systems, common and uncommon clinical features, diagnostic armamentarium and therapeutic and preventive aspects of neuropathies of leprosy.

The State of Affairs in Post-Exposure Leprosy Prevention: A Descriptive Meta-Analysis on Immuno- and Chemo-Prophylaxis

OBJECTIVE

Annually, over 200,000 people are diagnosed with leprosy, also called Hansen's disease. This number has been relatively stable over the past years. Progress has been made in the fields of chemoprophylaxis and immunoprophylaxis to prevent leprosy, with a primary focus on close contacts of patients. In this descriptive meta-analysis, we summarize the evidence and identify knowledge gaps regarding post-exposure prophylaxis against leprosy.

METHODS

A systematic literature search according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was conducted by searching the medical scientific databases Cochrane, Embase, Pubmed/MEDLINE, Research Gate, Scopus and Web of Science on Jan. 22, 2020, using a combination of synonyms for index terms in four languages: "leprosy" and "population" or "contacts" and "prevention" or "prophylaxis." Subsequently, Infolep.org and Google Scholar were searched and the "snowball method" was used to retrieve other potentially relevant literature. The found articles were screened for eligibility using predetermined inclusion and exclusion criteria.

RESULTS

After deduplication, 1,515 articles were screened, and 125 articles were included in this descriptive meta-analysis. Immunoprophylaxis by bacillus Calmette-Guérin (BCG) vaccination is known to provide protection against leprosy. The protection it offers is higher in household contacts of leprosy patients compared with the general population and is seen to decline over time. Contact follow-up screening is important in the first period after BCG administration, as a substantial number of new leprosy patients presents three months post-vaccination. Evidence for the benefit of re-vaccination is conflicting. The World Health Organization (WHO) included BCG in its Guidelines for the Diagnosis, Treatment and Prevention of Leprosy by stating that BCG at birth should be maintained in at least all leprosy high-burden regions. Literature shows that several vaccination interventions with other immunoprophylactic agents demonstrate similar or slightly less efficacy in leprosy risk reduction compared with BCG. However, most of these studies do not exclusively focus on post-exposure prophylaxis. Two vaccines are considered future candidates for leprosy prophylaxis: Mycobacterium indicus pranii (MiP) and LepVax. For chemoprophylaxis, trials were performed with dapsone/acedapsone, rifampicin, and ROM, a combination of rifampicin, ofloxacin, and minocycline. Single-dose rifampicin is favored as post-exposure prophylaxis, abbreviated as SDR-PEP. It demonstrated a protective effect of 57% in the first two years after administration to contacts of leprosy patients. It is inexpensive, and adverse events are rare. The risk of SDR-PEP inducing rifampicin resistance is considered negligible, but continuous monitoring in accordance with WHO policies should be encouraged. The integration of contact screening and SDR-PEP administration into different leprosy control programs was found to be feasible and well accepted. Since 2018, SDR-PEP is included in the WHO Guidelines for the Diagnosis, Treatment and Prevention of Leprosy.

CONCLUSION

Progress has been made in the areas of chemoprophylaxis and immunoprophylaxis to prevent leprosy in contacts of patients. Investing in vaccine studies, like LepVax and MiP, and increasing harmonization between tuberculosis (TB) and leprosy research groups is important. SDR-PEP is promising as a chemoprophylactic agent, and further implementation should be promoted. More chemoprophylaxis research is needed on: enhanced medication regimens; interventions in varying (epidemiological) settings, including focal mass drug administration (fMDA); specific approaches per contact type; combinations with screening variations and field-friendly rapid tests, if available in the future; community and health staff education; ongoing antibiotic resistance surveillance; and administering chemoprophylaxis with SDR-PEP prior to BCG administration. Additionally, both leprosy prophylactic drug registration nationally and prophylactic drug availability globally at low or no cost are important for the implementation and further upscaling of preventive measures against leprosy, such as SDR-PEP and new vaccines.

Post-exposure prophylaxis (PEP) efficacy of rifampin, rifapentine, moxifloxacin, minocycline, and clarithromycin in a susceptible-subclinical model of leprosy

BACKGROUND

Subclinical infection with Mycobacterium leprae is one potential source of leprosy transmission, and post-exposure prophylaxis (PEP) regimens have been proposed to control this source. Because PEP trials require considerable investment, we applied a sensitive variation of the kinetic mouse footpad (MFP) screening assay to aid in the choice of drugs and regimens for clinical trials.

METHODOLOGY/PRINCIPAL FINDINGS

Athymic nude mice were inoculated in the footpad (FP) with 6 x 103 viable M. leprae and treated by gastric gavage with a single dose of Rifampin (SDR), Rifampin + Ofloxacin + Minocycline (SD-ROM), or Rifapentine + Minocycline + Moxifloxacin (SD-PMM) or with the proposed PEP++ regimen of three once-monthly doses of Rifampin + Moxifloxacin (RM), Rifampin + Clarithromycin (RC), Rifapentine + Moxifloxacin (PM), or Rifapentine + Clarithromycin (PC). At various times post-treatment, DNA was purified from the FP, and M. leprae were enumerated by RLEP quantitative PCR. A regression analysis was calculated to determine the expected RLEP value if 99.9% of the bacilli were killed after the administration of each regimen. SDR and SD-ROM induced little growth delay in this highly susceptible murine model of subclinical infection. In contrast, SD-PMM delayed measurable M. leprae growth above the inoculum by 8 months. The four multi-dose regimens delayed bacterial growth for >9months post-treatment cessation.

CONCLUSIONS/SIGNIFICANCE

The delay in discernable M. leprae growth post-treatment was an excellent indicator of drug efficacy for both early (3-4 months) and late (8-9 months) drug efficacy. Our data indicates that multi-dose PEP may be required to control infection in highly susceptible individuals with subclinical leprosy to prevent disease and decrease transmission.

Opportunistic tropical infections in immunosuppressed patients

Autoimmune and autoinflammatory diseases are associated with severe morbidity, and represent an impactful health and economic burden worldwide. The treatment of these diseases can include a course with detrimental side effects. Immunosuppression increases the risk of opportunistic infections, but in some cases, the abrupt discontinuation of these medications can result in immune reconstitution inflammatory syndrome. Special attention must be directed to endemic tropical infections, such as leishmaniasis, Chagas disease, malaria, arbovirosis, yellow fever, leprosy, paracoccidioidomycosis, disseminated strongyloidiasis, and ectoparasitosis. These endemic diseases of developing countries can be considered as possible emerging diseases in developed regions partially because of environmental factors and migration. In the present article, we aim to review the evidence-based aspects of the most important opportunistic tropical infections in immunosuppressed patients. We also aim to review the important aspects of vaccination, chemical prophylaxis, and treatment for these infections in people with medication-induced immunosuppression.

Leprosy: Treatment and management of complications

In the second article in this continuing medical education series, we review the treatment of leprosy, its immunologic reactions, and important concepts, including disease relapse and drug resistance. A fundamental understanding of the treatment options and management of neuropathic sequelae are essential to reduce disease burden and improve patients' quality of life.

Protocol, rationale and design of PEOPLE (Post ExpOsure Prophylaxis for LEprosy in the Comoros and Madagascar): a cluster randomized trial on effectiveness of different modalities of implementation of post-exposure prophylaxis of leprosy contacts

Background

Leprosy is an ancient infectious disease with a global annual incidence that has plateaued above 200,000 new cases since over a decade. New strategies are required to overcome this stalemate. Post-exposure prophylaxis (PEP) with a single dose of Rifampicin (SDR) has conditionally been recommended by the World Health Organization (WHO), based on a randomized-controlled-trial in Bangladesh. More evidence is required. The Post ExpOsure Prophylaxis for Leprosy (PEOPLE) trial will assess effectiveness of different modalities of PEP on the Comoros and Madagascar.

Methods

PEOPLE is a cluster-randomized trial with villages selected on previous leprosy-incidence and randomly allocated to four arms. Four annual door-to-door surveys will be performed in all arms. All consenting permanent residents will be screened for leprosy. Leprosy patients will be treated according to international guidelines and eligible contacts will be provided with SDR-PEP.

Arm-1 is the comparator in which no PEP will be provided. In arms 2, 3 and 4, SDR-PEP will be provided at double the regular dose (20 mg/kg) to eligible contacts aged two years and above. In arm 2 all household-members of incident leprosy patients are eligible. In arm 3 not only household-members but also neighbourhood contacts living within 100-m of an incident case are eligible. In arm 4 such neighbourhood contacts are only eligible if they test positive to anti-PGL-I, a serological marker. Incidence rate ratios calculated between the comparator arm 1 and each of the intervention arms will constitute the primary outcome.

Discussion

Different trials on PEP have yielded varying results. The pivotal COLEP trial in Bangladesh showed a 57% reduction in incidence over a two-year period post-intervention without any rebound in the following years. A study in a high-incidence setting in Indonesia showed no effect of PEP provided to close contacts but a major effect of PEP provided as a blanket measure to an entire island population. High background incidence could be the reason of the lack of effect of PEP provided to individual contacts. The PEOPLE trial will assess effectiveness of PEP in a high incidence setting and will compare three different approaches, to identify who benefits most from PEP.

Trial registration

Clinicaltrials.Gov. NCT03662022. Initial Protocol Version 1.2, 27-Aug-2018.

Predicting the impact of household contact and mass chemoprophylaxis on future new leprosy cases in South Tarawa, Kiribati: A modelling study

Background

The country of Kiribati is a small Pacific island nation which had a new case detection rate of 191 per 100,000 in 2016, and is one of the few countries yet to reach the WHO leprosy elimination goal. Chemoprophylaxis of household contacts of new cases, or to the whole population in a highly endemic areas have been found to be effective in reducing new case rates. This study investigated the potential impact of different chemoprophylaxis strategies on future cases in South Tarawa, the main population centre of Kiribati.

Methodology

The microsimulation model SIMCOLEP was calibrated to simulate the South Tarawa population and past leprosy control activities, and replicate annual new cases from 1989 to 2016. The impact of six different strategies for delivering one round of single dose rifampicin (SDR) chemoprophylaxis to household contacts of new cases and/or one or three rounds of SDR to the whole population was modelled from 2017 to 2030.

Principal Findings

Our model predicted that continuing the existing control program of high levels of public awareness, passive case detection, and treatment with multidrug treatment would lead to a substantial reduction in cases but this was less effective than all modelled intervention scenarios. Mass chemoprophylaxis led to a faster initial decline in cases than household contact chemoprophylaxis alone, however the decline under the latter was sustained for longer. The greatest cumulative impact was for household contact chemoprophylaxis with three rounds of mass chemoprophylaxis at one-year intervals.

Conclusions

The results suggest that control of leprosy would be achieved most rapidly with a combination of intensive population-based and household chemoprophylaxis. These findings may be generalisable to other countries where crowding places social contacts as well as household contacts of cases at risk of developing leprosy.

Leprosy rates in Kiribati are some of the highest in the world and it is one of the few countries yet to reach the World Health Organization leprosy elimination goal of a prevalence of less than one case per 10,000 population. The greatest burden is in the capital South Tarawa and the connected islet of Betio. Interest has increased for the use of chemoprophylaxis, the administration of preventive antibiotics to apparently healthy individuals who may be incubating the disease, which has been demonstrated to be effective in both household contacts and the whole population in two recent studies. In this study we used the individual-based model SIMCOLEP to predict the impact of six difference scenarios using single dose rifampicin (SDR) chemoprophylaxis in household contacts and/or the entire population on future new cases in South Tarawa. We found that all chemoprophylaxis strategies were predicted to be more effective than the current control strategy, particularly a combination of household contact chemoprophylaxis alongside three rounds given to the entire population in consecutive years.

[What's new in clinical dermatology?]

In this article, we performed a review of all new data of clinical relevance for the dermatologists that were published in the medical literature between September, 2017 and September, 2018. Besides advances that will be useful in day-to-day dermatological practice, we intended to give a more general perspective to this review by taking into account certain international health issues that might in final concern each of us in a globalized world. Focus were more particularly done on the following topics: infectious diseases (including sexually transmitted infections), neglected tropical diseases, adverse effects of drugs, bullous diseases, allergology, wound healing, dermatology on black skin, and public health dermatology.