This week, @Vaccines is curated by Dr. Anuj Bhattachan, a physician, blogger and traveller from Nepal, passionate about global health, poverty and equity issues in low income settings. Dr. Anuj has been involved with the Global Polio Eradication Initiative (GPEI) since 2005 and will tweet about how vaccines work in Pakistan, with a particular focus on Supplementary Immunization Activities (SIA) in Karachi. He has also promised to share stories and thoughts from front-line workers fighting to end polio in Pakistan and around the world. Tune in to @Vaccines and follow along!