Health Editor, BBC News online
A new study of people who have caught and recovered from coronavirus raises the prospect that immunity to the virus may be short-lived.
Scientists at King’s College London studied how the body naturally fights off the virus by making antibodies, and how long these last in the weeks and months after recovery.
Almost all of the 96 people in the study had detectable antibodies that could neutralise and stop coronavirus. But levels began to wane over the three months of the study.
What’s not clear yet is whether this decline leaves us vulnerable to the same virus again. Similar short-lived responses are seen with other viruses, like the common cold. So it’s possible that we may be able to get re-infected.
But even if we’re left with no detectable antibodies, that doesn’t necessarily mean we have no immunity. Antibodies are not the only thing that gives us protection. Our bodies can also make T cells to help fight off invaders.
More and longer studies are needed to see what happens if people come into contact with the virus a second or third time. Do they get sick or are they primed to fight it off because their body has already done so before? These types of study will be important for understanding how well a vaccine might work and how often a booster dose might be needed to provide lasting immunity.