According to the WHO, about six per cent of people worldwide who get Covid later develop a long-lasting form of the illness. That shows the condition remains a significant public health challenge. In 2021, Belgian researchers launched a study to see whether long-term symptoms could be predicted during the acute phase of infection.

After five years of research, scientists identified an important role for Dolosigranulum pigrum, a bacterium that naturally lives in the respiratory microbiome. Higher levels of this bacterium were associated with a lower likelihood that long Covid symptoms would persist.