For example, the word, "fever" for nowcasting, and the word, "injection" for forecasting.
most systems have simply aggregated counts of daily flu-related tweets to obtain the current patient status (Aramaki et al., 2011;Collier et al., 2011;Chew and Eysenbach, 2010;Lampos and Cristianini, 2010;Culotta, 2013;Paul et al., 2014).