Numrah Shakeel Malik, Muhammad Umair, Farah Qasim, Ayesha Azam, Muhammad Muddassar, & Rimsha Qasim. (2023). Does the COVID vaccine really help? A cross-sectional study to assess the positivity rate among Health Care Workers and staff members at tertiary care hospitals. Pakistan Journal of Chest Medicine, 29(3), 329–336. https://doi.org/10.1996/pjcm.v29i3.829