The potential impact of programmes interruptions due to COVID-19 on 7 neglected tropical diseases: a modelling-based analysis

The COVID-19 pandemic has interrupted NTD programs worldwide, from mass drug administration to active case finding activities. The NTD Modelling Consortium recently conducted modelling analyzing the impact of COVID-19 on seven NTDs and potential strategies to mitigate the impact of COVID-related delays:

"Executive Summary Background:

The spread of SARS-CoV-2 (COVID-19) will impact the progress of neglected tropical disease (NTD) programmes. In the short term, World Health Organization (WHO) guidance advises that many NTD surveys, active case finding activities, and mass drug administration (MDA) campaigns should be postponed, whilst support for prompt diagnosis, treatment, and essential vector control should continue where possible (WHO, 2020). Understanding if these interruptions will erode previous gains and, therefore, what can be done to prevent or make up for increases in transmission or resurgence, is essential. This report describes mathematical modelling insights on how NTD programmes could be impacted by the interruption of interventions and what remedial strategies could be implemented once programmes resumes. Questions posed in this report: How much delay programmes can tolerate before they start seeing a negative impact in achieving the 2030 goals? In which settings will delay-related impacts be greatest? What remedial strategies can be implemented once programmes resume to mitigate the impact of delays?

Summary:

• The underlying disease dynamics for each NTD, as well as the transmission setting, will impact the rate of resurgence that programmes will face during this delay due to COVID-19.
• Our analyses suggest that many NTD programmes should be able to recover froma brief delay particularly when the rates at which infection resurges are slow in the absence of interventions.
• However, longer delays will require more intensive remedial strategies to get back on trackand will translate into greater accrued burden of morbidity.
• High transmission areas face the greatest risk, as resurgence will be high in these areas.
• Amongst the diseases for which MDA is the main intervention, trachoma and schistosomiasis are likely to see the quickest bounce back, particularly in hightransmission areas.
• More intensive remedial strategies are, therefore, required for trachoma and schistosomiasis such as extra rounds of MDA or changing the MDA target population, respectively, to resume or even to accelerate progress towards the 2030 goals.
• There is an increased risk of undetected outbreaks of visceral leishmaniasis in the Indian sub-continent and hence active case detection activities should resume as soon as possible to detect any increase in underlying infections.

Local context: The results outlined here are average results for general scenarios, and the actual impact will depend on the local context. For example, the stage and effectiveness of the programmes will also play a role in the resurgence rate. Programmes in their early stages will return towards pre-treatment endemicity levels more quickly, whereas programmes in later stages -which have managed to reduce/control transmission -will experience lower levels of resurgence, provided the residual transmission rate is not too high."