covid疫苗保护将持续多长时间？
researchers and health experts say they don't know for sure. on its official web faq, the cdc says, 'we won't know how long immunity lasts after vaccination until we have more data on how well covid-19 vaccines work in real-world conditions.' 也就是说，moderna首席执行官stephane bancel拥有 offered a rough window: 'we believe there will be protection potentially for a couple of years.'
接种疫苗的人大大降低了从病毒中生病的机会，但是疫苗试验并未确定一个人在接种疫苗后是否仍具有传染性。 'we just 尚不知道答案 to (that) question,' said dr. jaime sepulveda, executive director of the institute for global health sciences at the university of california, san francisco. 'the clinical trials were not designed to have that as an endpoint.'