The US Food and Drug Administration (FDA) on Monday added a warning to the fact sheet for Johnson & Johnson's (J&J) Covid-19 vaccine saying that data suggests there is an increased risk of a rare neurological disorder in the six weeks after inoculation.

In a letter to the company, the FDA classified the chances of getting Guillain-Barré syndrome (GBS) after vaccination as being "very low." Still, it said J&J vaccine recipients should seek medical attention if they have symptoms including weakness or tingling sensations, difficulty walking or difficulty with facial movements...