RIYADH — The Ministry of Health announced that half of the Kingdom’s population has become immune by at least one dose of vaccine against coronavirus. Dr. Muhammad Abdel Ali, spokesman of the ministry, said that about 20 percent of the population has so far received two doses of the vaccine. He hinted at the possibility of booking for the second dose of the coronavirus vaccine, at least three weeks after taking the first dose. Addressing the daily press briefing on Sunday, The spokesman said that one dose of the vaccine is not enough to prevent the mutated Delta virus. “Delta is the most dangerous mutated variant of coronavirus because of the speed of its spread, and that the worrisome mutant besides Delta are Alpha, Beta, and Gamma. Two doses of the vaccine must be taken to prevent the fastest spreading Delta variant,” he said. He called on the Saudi citizens and residents to hurry up to take two doses of the vaccine, while pointing out that the ministry has expanded the availability of getting appointment dates for taking doses. The spokesman reiterated the possibility of taking two doses of two different vaccines. Total coronavirus cases in the Kingdom have reached 518,143 cases, including 10,847 active cases and 1,408 critical cases, while the recovery cases reached 499,129. The total number of death cases rose to 8,167. He urged the public to contact with the ministry’s toll free number 937 for consultations and inquiries around the clock, to obtain authentic health information and services, as well as to know the latest developments pertaining to coronavirus. In a related development, the Ministry of Islamic Affairs, Call and Guidance reopened two mosques in Riyadh and Jazan after temporarily evacuating and sterilizing following confirmation of coronavirus infection among the worshipers. The ministry sources stated that these measures have been taken to further ensure the safety of worshipers, in addition to the continuous cleaning and maintenance of all mosques. The number of mosques that were reopened after sterilization within the last 169 days reached 1,893.