Waseem Iqbal, Ikram Ullah, Uroosa Irum, Saima Siddiqi and Khalid Mahmood Khan 2023. An Estimate of Protective Immunity against SARS-CoV2: Comparison of Different Vaccine Types. Proceedings of the Pakistan Academy of Sciences: B. Life and Environmental Sciences. 60, 3 (Aug. 2023), 377–382. DOI:https://doi.org/10.53560/PPASB(60-3)749.