A prospective cohort study protocol: monitoring and surveillance of adverse events following heterologous booster doses of Oxford AstraZeneca COVID-19 vaccine in previous recipient... oleh Shahin Soltani, Behzad Karami Matin, Mohammad Mehdi Gouya, Sayed Mohsen Zahraei, Ghobad Moradi, Omid Chehri, Moslem Soofi, Mehdi Moradinazar, Fatemeh Khosravi Shadmani, Mahsa Kalantari, Hamidreza Khajeha, Mohammad Hassan Emamian, Farid Najafi