Possible vaccine timelines

<img width=“750” height=“406” src=“https://i1.wp.com/flowingdata.com/wp-content/uploads/2020/04/vaccine-timeline.png?fit=750%2C406&ssl=1" class=“attachment-medium size-medium wp-post-image” alt=“” srcset=“https://i1.wp.com/flowingdata.com/wp-content/uploads/2020/04/vaccine-timeline.png?w=2036&ssl=1 2036w, https://i1.wp.com/flowingdata.com/wp-content/uploads/2020/04/vaccine-timeline.png?resize=750%2C406&ssl=1 750w, https://i1.wp.com/flowingdata.com/wp-content/uploads/2020/04/vaccine-timeline.png?resize=1090% …