Zero Transmission
Indicator
2018
2019
2020
2021
2022
New leprosy cases (TLM projects)
11.215
10.949
7.966
9.423
10.169
Getting back on track after the pandemic
After a severe drop in new cases in 2020 and 2021 due to pandemic restrictions on travel and movement, our projects reported 10,169 new cases in 2022.
Although an increase of leprosy cases sounds like transmission is increasing, it in fact means that we are finding hidden cases and providing them with treatment. Once a person has started treatment, they are no longer infectious.
Once a person has been diagnosed, we can also prevent and manage leprosy-related disability.
We are celebrating this increase in cases and hoping to see further increases in the years to come before an eventual downturn as we interrupt the transmission of leprosy.
A major victory: fewer children with visible impairments
We are working towards a day when no child is diagnosed with leprosy. In 2022, we diagnosed more children with leprosy than we did in 2021 and 2020. However, what is noteworthy is that fewer of those children had visible impairments.
That is a big cause for celebration, not just because we have prevented needless pain in the lives of each of those children, but because of the impact on leprosy transmission.
The incubation period for leprosy varies widely, ranging from a few months to even 20 years or more. Therefore, it can be challenging to determine whether an adult newly diagnosed with leprosy contracted the disease recently or in the distant past, as they may not show external symptoms for many years. Conversely, when diagnosing leprosy in children who are under the age of 15, it provides a strong indication that they contracted the disease relatively recently, depending on their age. Therefore, the presence of leprosy in children serves as a robust indicator of recent and active community transmission of the disease,
as children have not lived long enough to have contracted it many years ago. If we are finding fewer visible impairments amidst a higher total number of child cases, this is an indication that we have been efficient in detection and diagnosis; we caught the cases early, when they were recently infected, and before the impairments could advance. If we can learn from what has worked well and enabled us to achieve that success and then replicate that globally in the years to come, we will move ourselves closer to that day when no more children are diagnosed with leprosy.
Child new cases (TLM projects) [KPI3]
976
893
587
639
666
Child new cases with grade 2 disability [KPI4]
88
60
45
42
23
Taking steps to find new cases and preventing transmission
In recent years, we have seen a growth in awareness of the importance of three crucial methods for interrupting leprosy transmission:
Active case finding in selected populations,
Contact screening and,
Providing preventative antibiotics, known as post-exposure prophylaxis (PEP)
We have scaled up all three methods in our programmes in an effort to ‘bend the curve’ of new cases detected, towards the interruption of leprosy transmission.
We are celebrating that, in 2022, we screened more than half a million contacts of leprosy patients. Among these, we found more than a thousand people with signs of active leprosy disease, whom we have been able to place on treatment.
We are committed to perfecting these three initiatives, so that we do them as well as we can across each country. We have set up processes within The Leprosy Mission to share best practice and, in 2022, we ran a rapid-assessment of our active-case finding activities to see what we could learn and expand from one country to another.
We have three key reasons to be hopeful about the future of leprosy transmission.
Diagnostic tests
The current method for confirming the diagnosis of leprosy is not simple. It requires taking a slit skin smear and sending it to a lab for testing. This takes time, and delays in diagnosis sometimes lead to people not being diagnosed, especially in contexts where people move around often.
Thankfully, there are teams across The Leprosy Mission and our partner organisations who are working on a number of fast, field-friendly diagnostic tests. In the next few years, these tests could revolutionise leprosy diagnosis. You can hear more about this in this recording of a webinar with Professor Dr Annemieke Geluk.
© Sabrina Dangol
2. Post-exposure prophylaxis (preventative antibiotics)
This is a tool that we already have in our toolbox. It reduces the risk of development of leprosy disease in contacts of leprosy cases. However, it is a tool that we are looking to make more powerful. There are two ways to do this. Firstly, what is the most effective way to implement PEP? Secondly, are there more effective antibiotic regimens for preventing leprosy? Our researchers – or our partners’ researchers - are looking at both of these questions to make our efforts to prevent the spread of leprosy far more effective in the years to come. You can read more about the potential of PEP here.
3. Leprosy vaccines
There are several leprosy vaccines that are currently under development. The Leprosy Mission supports LepVax through the Leprosy Research Initiative. LepVax is currently undergoing clinical trials in Brazil. Although we are some years away from a leprosy vaccine being ready for a global rollout, there is a realistic possibility of this happening before 2035, which is a real reason to believe that we can end the transmission of leprosy by that date.
