A new warning has been placed on the Johnson & Johnson coronavirus vaccine after reports of increased risk in nerve disorders have been linked to those who received the single-dose inoculation. The US Food and Drug Administration updated the brand’s fact sheet on Monday, however it has not yet fully established if the vaccine causes such complications on the nervous system.

In its letter to Johnson & Johnson about its Janssen vaccine, the FDA said it is revising the brand’s vaccine recipient information sheet to include observation studies that incurred increased risk of Guillain-Barré Syndrome (GBS) in people six weeks after receiving the one-time jab.

As per the US Centers for Disease Control and Prevention (CDC), “GBS is a neurological disorder in which the body's immune system damages nerve cells, causing muscle weakness or in the most severe cases paralysis.”

FDA data showed that 100 preliminary reports of vaccine recipients have experienced adverse effects similar to GBS, with most manifesting symptoms 42 days following vaccination. Out of the 100, 95 were serious cases that needed hospitalization and one died, CNN reported.

Evidential symptoms of GBS to look out for include tingling in both upper and lower extremities, weakness, difficulty in walking, speaking, chewing and swallowing as well as inability to control bowel/bladder movement and double vision.

The FDA has advised to seek medical attention should anyone notice these symptoms.

Johnson & Johnson confirmed in an official statement that they are working closely with the CDC and FDA to sort out the vaccine’s concerning issues.

Earlier this year, the FDA along with the CDC put a hold on the Johnson & Johnson vaccine due to reports of a rare type of blood clotting complication. After having determined the low risks of the complication and evidence of successful treatments, the pause was lifted. However, the agency has now included a warning on the vaccine label about the increased risk of acquiring the condition.

On the other hand, the CDC emphasized the importance of getting a Covid-19 vaccine despite the increased risk of acquiring GBS, stressing that the chances of this occurrence is quite low.

Janssen has rolled out around 12.8 million doses in the United States. With the revision in place, the new Johnson & Johnson label reads: "Although the available evidence suggests an association between the Janssen vaccine and increased risk of GBS, it is insufficient to establish a causal relationship. No similar signal has been identified with the Moderna and Pfizer-BioNTech COVID-19 vaccines." 

J&J Janssen Covid-19 vaccine A health worker is holding a Janssen Covid-19 vaccine ready to be used on June 25, 2021 in Nieuwegein, Netherlands. The Dutch government this week made it possible to make an injection appointment for everyone who wants to be vaccinated with Janssen. Photo by Patrick van Katwijk/BSR Agency/Getty Images