For covid vaccines, there is currently a trial in the UK studying the outcomes on alternating doses of different vaccines. A positive outcome would be signific

For covid vaccines, there is currently a trial in the UK studying the outcomes on alternating doses of different vaccines. A positive outcome would be significantly increase flexibility in scheduling second shots. From what I understand, mixing vaccines is not a new strategy for vaccinations in general (it's called heterologous prime-boost) and can provide enhanced immunity. https://www.advisory.com/daily-briefing/2021/04/01/vaccine-mix https://www.advisory.com/daily-briefing/2021/04/01/vaccine-m...