…maybe as many as 100 million doses by early 2021″ would be possible, Collins said.
The third and final phase of trials testing an experimental vaccine developed by Massachusetts-based biotech firm Moderna will begin in July. A few other vaccine candidates, including one developed by U.K.-based pharmaceutical company AstraZeneca, are also showing promise, according to Fauci.
Dr. Greg Poland, director and founder of Mayo Clinic Vaccine Research Group, said natural immunity from coronaviruses SARS-CoV-1 and MERS can be detected two to three years after recovering from infection. However, immunity for seasonal coronaviruses can last as little as 80 days to several years in some people.