  Detecting changes in COVID-19 disease transmission over time is a key
indicator of epidemic growth. Near real-time monitoring of the pandemic growth
is crucial for policy makers and public health officials who need to make
informed decisions about whether to enforce lockdowns or allow certain
activities. The effective reproduction number Rt is the standard index used in
many countries for this goal. However, it is known that due to the delays
between infection and case registration, its use for decision making is
somewhat limited. In this paper a near real-time COVINDEX is proposed for
monitoring the evolution of the pandemic. The index is computed from
predictions obtained from a GAM beta regression for modelling the test positive
rate as a function of time. The proposal is illustrated using data on COVID-19
pandemic in Italy and compared with Rt. A simple chart is also proposed for
monitoring local and national outbreaks by policy makers and public health
officials.
