In Israel's COVID-19 wards, around half of the country's 600 patients presently hospitalized with severe illness have received two doses of the Pfizer Inc shot — a rare occurrence out of 5.4 million fully vaccinated people. The majority of the patients are over the age of 60 and also have chronic illnesses known to exacerbate a coronavirus infection, according to Reuters interviews with 11 doctors, health specialists and officials.