This is all the source code used for the following paper: Salathé M, Khandelwal S, 2011 Assessing Vaccination Sentiments with Online Social Media: Implications for Infectious Disease Dynamics and Control. PLoS Comput Biol 7(10): e1002199. doi:10.1371/journal.pcbi.1002199 Please cite the paper above, if you use our code or create a derivative work. The analysis/ directory contains all the code for the sentiment analysis (based on NLTK/MegaM). It also containst the geocoding code. The student_ratings directory contains Python/Django code to let students rate tweets (as described in our paper). The Django code assumes a MySQL backend. The code as written originally was designed to work with the original tweet ids, tweeter ids etc from Twitter. A lot of the scripts assume certain files exist (some of those have not been checked into this public repository). In those cases some changes will be necessary. If you need help navigating the code, let us know. khandelwal@psu.edu, salathe@psu.edu