Nearly all children in the UK catch chickenpox by the age of 10, and it is considered a fairly benign virus for most. However, once you have cleared chickenpox, it remains inactive in your nerve tissue, and in one in three adults it reactivates to cause shingles, a condition resulting in a painful rash.

While we cannot rule out reactivation as a possibility yet, it still seems more probable that these 91 cases were either due to the levels of the virus dipping below a detectable level, allowing symptoms to improve, but then surging again, or that there were flaws with the tests, where the clearance samples were false negatives. The tests are not perfect and, from the data received from China, the most commonly used type of test showed up to a 30 percent false-negative rate.

As South Korea investigates this further and other countries are able to offer their own findings, we are likely to understand more about the way this virus summons an immune response and, hopefully, determine for sure whether reactivation or reinfection are possibilities.

Doctor’s Note: Can the coronavirus reactivate? | Doctor’s Note | Al Jazeera