Janssen Vaccine Can Rarely Cause Neurological Reaction

US Food and Drug Administration (FDA) updated the warning that Janssen vaccine may include minimal risk of developing Guillan Barré syndrome (GBS).

The warning states that the symptoms began within 42 days after the vaccination and that "the chance of this happening is very low".

Since the vaccination with Janssen began in the United States, the Centers for Disease Control and Prevention (CDC) has received reports of 100 vaccinated individuals who have subsequently developed this immune system disorder that can cause muscle weakness and occasional paralysis.

However, the report represents only a fraction, as nearly 13 million Americans have taken the vaccine, which requires only one dose. Most cases were registered in men, many 50 years and older, usually two weeks after the vaccine dose was set.

The manufacturer Johnson & Johnson says in a statement that the company has discussed the reports of the side effect with the FDA and health authorities in other countries.

According to US authorities, no cases of the disease have been reported after vaccination with the mRNA vaccines from Pfizer and Moderna.

GBS is a neurological disorder in which the body's immune system damages nerve cells, causes muscle weakness or, in the most severe cases, paralysis.

The disease affects between 3,000 and 6,000 people in the United States annually, and most recover.

The syndrome can be triggered by a variety of infections, including influenza, cytomegalovirus and Zika virus. In some rare cases, people have developed the disease days or weeks after receiving certain vaccines.