This paper summarises key advances in defining the infectious
reservoir for malaria and the measurement of transmission for
research and programmatic use since the Malaria Eradication
Research Agenda (malERA) publication in 2011. Rapid and
effective progress towards elimination requires an improved
understanding of the sources of transmission as well as those at
risk of infection. Characterising the transmission reservoir in
different settings will enable the most appropriate choice,
delivery, and evaluation of interventions. Since 2011, progress
has been made in a number of areas. The extent of submicroscopic
and asymptomatic infections is better understood, as are the
biological parameters governing transmission of sexual stage
parasites. Limitations of existing transmission measures have
been documented, and proof-of-concept has been established for
new innovative serological and molecular methods to better
characterise transmission. Finally, there now exists a concerted
effort towards the use of ensemble datasets across the spectrum
of metrics, from passive and active sources, to develop more
accurate risk maps of transmission. These can be used to better
target interventions and effectively monitor progress toward
elimination. The success of interventions depends not only on
the level of endemicity but also on how rapidly or recently an
area has undergone changes in transmission. Improved
understanding of the biology of mosquito-human and
human-mosquito transmission is needed particularly in
low-endemic settings, where heterogeneity of infection is
pronounced and local vector ecology is variable. New and
improved measures of transmission need to be operationally
feasible for the malaria programmes. Outputs from these research
priorities should allow the development of a set of approaches
(applicable to both research and control programmes) that
address the unique challenges of measuring and monitoring
transmission in near-elimination settings and defining the
absence of transmission