Much of the messaging from authorities around Covid-19 booster shots has been confusing — and that’s partly because scientists themselves haven’t always agreed on who needs them. When many countries began to recommend boosters not just for the older and high-risk, but for all adults, they were essentially taking sides in a still-unresolved debate around that question: Why give an extra dose to healthy adults who are still very protected against severe Covid-19 cases from their original dose?
But since the omicron variant has emerged, many have changed their minds. To understand why, we talked to one formerly skeptical expert who scheduled her own booster shot based on what she learned about omicron. We spoke to her about what happens in your immune system when you get that third (or second) shot, and why it could be especially useful in stopping the spread of omicron.