Sentiment Analysis (SA) is the study of the datasets available over web that contains fruitful information. Machine learning techniques have a great role in computer science. One of the applications of machine learning techniques is to study patterns and development of such computational systems that can learn themselves and make predictions. In recent past there are examples of studies in which data sets are taken from microblogging websites like Twitter etc. and significant healthcare information generated by sentiment analysis of data sets. In this research article, (i) significance of sentiment analysis in predictions is described; (ii) relevance of sentiment analysis using Machine Learning (ML) techniques is studied; (iii) classification of data based on ML techniques is also described; (iv) survey on use of microblogging sites to predict the outbreaks and epidemics is done through some major research articles from year 2010 to 2017.