NUMRAH SHAKEEL MALIK; MUHAMMAD UMAIR; FARAH QASIM; AYESHA AZAM; MUHAMMAD MUDDASSAR; RIMSHA QASIM. 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, [S. l.], v. 29, n. 3, p. 329–336, 2023. DOI: 10.1996/pjcm.v29i3.829. Disponível em: https://www.pjcm.net/index.php/pjcm/article/view/829. Acesso em: 30 oct. 2025.