Leprosy Mailing List – November 2, 2020
Ref.: (LML) Rapid interruption of transmission: annual skin camps followed by "blanket" ROM + MDT (prolonged for LL patients)
From: Joel Almeida, London and Mumbai
Dear Pieter and colleagues,
Very interesting presentations and discussions have been going on about the new draft WHO strategy for 2021-2030. WHO must be commended for opening up the consultation to a wider range of inputs. My thoughts after hearing various excellent presenters were along these lines.
Anti-microbial resistance (AMR) might deserve a strategy for not just monitoring but also prevention. Already 10% of tested patients show drug-resistant bacilli. (1). Without a deliberate strategy to contain drug resistance, past gains could be compromised and reversed. Use of single drugs in highly bacillated patients with poor natural immunity is likely to be an important contributor to AMR. Unfortunately the subtle signs of early LL HD easily can be missed, even by experts. All these difficulties concerning AMR can be bypassed by making expertise more mobile (e.g., skin camps), simply avoiding the use of single drugs, and always insisting on multiple drugs in every context.
Repeated blanket administration of a single bolus of multiple drugs (rifampicin + ofloxacin + minocycline, ROM) in the Federated States of Micronesia is the only form of chemoprophylaxis so far which both had good epidemiological impact (at least temporarily) and was relatively unlikely to favour drug-resistant mutant bacilli. It was administered to most of the population on specific islands only twice in the 1990s. (2) Yet a favourable epidemiological impact was discernible temporarily. The subsequent resurgence in HD was probably because of missed LL patients during implementation. Mobile skin camps with expert clinicians are a useful way to improve the diagnosis of early LL HD (and other skin conditions). If all LL patients had been diagnosed just before each "blanket" drive, and if the blanket administration had been repeated a few more times, Micronesia might well have succeeded in achieving zero transmission fairly rapidly.
The situation in refugee camps, war zones, hard-to-access populations etc might benefit from such special strategies for disease control. South Sudan, for example, might struggle to implement normal approaches. It might benefit from a similar intervention as used in Micronesia (repeated blanket administration of ROM or similar multi-drug prophylaxis after periodic skin camps).
Blanket administration does not expose the private health information of any newly diagnosed index patient. It has a good epidemiological impact and discourages AMR. In endemic areas less than 10% to 20% of new patients come from among household contacts of known patients. (3) And, single drugs unavoidably favour drug-resistant mutant bacilli. All these points favour repeated "blanket" administration of ROM (or similar bactericidal combinations) in challenging areas. This could work well even outside challenging special situations. Repeated blanket ROM would complement MDT. MDT would be prolonged till smear negativity for LL HD patients but would remain "fixed duration" for all others, .
Interestingly, the Sasakawa Health Foundation was involved in sponsoring both of these key interventions in their infancy. First MDT, and then blanket ROM prophylaxis. Whenever funders act with a light touch, the talents and abilities of people can be unleashed and space is created for very good things to happen.
With Novartis having successfully issued a USD1.25bn bond explicitly linked to social goals including expanding access to effective interventions in HD, the additional costs of ROM or similar should not be a serious obstacle. It would be in Novartis' own interests to favour the most effective and safe interventions in HD. For chemoprophylaxis, the evidence favours repeated blanket administration of ROM as previously used in Micronesia rather than single dose single drug options which are both ineffective and problematic at many levels.
Given all the above, the current most reliable and rapid route to rapid zero transmission is probably:
Skin camps with visiting expert clinicians to help diagnose especially LL HD and exclude TB, followed by
MDT (in patients who ever showed a high BI this would be prolonged until smear negativity) plus
blanket ROM (or similar multi-drug chemoprophylaxis).repeated at annual intervals.
Annual intervals are likely to suffice assuming a 12 day doubling time among bacilli, because that will permit a single bacillus to reach no more than about 1 billion bacilli. That is as much as full blown LL patients can shed in one single nose blow. If necessary the interval can be shortened to less than a year.
The mobile team of experts could also do training/refresher training for local multi-purpose workers and patients, to help improve life and ensure awareness of rights and entitlements for people with a range of conditions.
It seems feasible. Wouldn't it be good to have real success, and reasonably rapidly?
Regards,
Joel Almeida
References
1. WHO. WER No 36, 2020, 95, 417–440
2. WORKSHOP ON THE PREVENTION OF LEPROSY, POHNPEI, FEDERATED STATES OF MICRONESIA. 25-27 MAY 1999 sponsored by the Sasakawa Memorial Health Foundation Tokyo, Japan and the Western Pacific Regional Office of the World Health Organization. Int J Lepr, 67 (4) (SUPPLEMENT)
3. Butlin CR, Nicholls PG, Bowers B, et al. Outcome of late healthy household contact examinations in leprosy-affected households in Bangladesh. Lepr Rev. 2019; 90 (3): 305–320
LML - S Deepak, B Naafs, S Noto and P Schreuder
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