Howto Use Should Have. Should have is used to say that a different action should have occurred in the past. It also can be used to suggest that a different action in the past would have been a better choice. For example: I should have picked up dinner on the way home from work. I should have studied more for that test.
Accordingto the current Canadian Immunization Guide, regardless of any previous booster doses, fully-vaccinated adults 65 and older should have received one booster doses since the start of fall.
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