People 65 years and older and those who are moderately or severely immunocompromised should receive a second dose of 2024-2025 COVID-19 vaccine six months after their first dose. See the CDC's updated guidance. More Info
No. Information about the studies and the candidates can be found on the following website https://coronaviruspreventionnetwork.org/understanding-clinical-studies/ or by visiting the manufactures websites.