Characterizing measles transmission in India: a dynamic modeling study using verbal autopsy data.

Area of Science:

• Epidemiology
• Mathematical Modeling
• Public Health

Background:

• Previous measles mortality estimates relied on assumed regional case fatality risks (CFRs).
• These estimates often overlooked crucial mortality data from low- and middle-income countries, particularly India, which bears the highest global measles burden.

Purpose of the Study:

• To develop a data-driven dynamic model for estimating measles transmission and mortality in India.
• To calculate measles case fatality risks (CFRs) and assess the impact of vaccination on under-five children from 2000-2015.
• To provide accurate estimates for India and its high-burden states, Bihar and Uttar Pradesh.

Main Methods:

• Constructed a dynamic measles transmission model for India.
• Empirically inferred model parameters using spectral analysis of mortality data from the Million Death Study.
• Utilized verbal autopsy data from 2.4 million Indian households to attribute causes of death.

Main Results:

• Estimated measles CFRs for under-five children in 2005: 0.63% for India, 0.62% for Bihar, and 1.19% for Uttar Pradesh.
• Estimated 607,000 under-five measles deaths in India between 2000-2015.
• Calculated that routine and supplemental vaccination prevented an additional 1.6 million under-five deaths in India during the same period.

Conclusions:

• Developed a robust, data- and model-driven estimation of historical measles dynamics in India.
• Quantified the significant impact of vaccination in reducing measles mortality among Indian children.
• Highlighted the importance of accurate CFR and transmission parameter estimation for understanding disease burden and intervention effectiveness.