Study: Guillain-Barré risk with COVID-19 vaccines low, but higher with J&J shot

April 26 (UPI) -- The risk for developing Guillain-Barré syndrome, a condition that causes severe muscle weakness, after receipt of a COVID-19 vaccine is small, but higher with the Johnson & Johnson shot, according to a study published Tuesday.

Of recipients of more than 480,000 doses of the one-shot Johnson & Johnson vaccine, 11 cases of Guillain-Barré syndrome were reported, the data, published Tuesday by JAMA Network Open, showed.

Among recipients of one of the two-shot mRNA vaccines from Moderna or Pfizer-BioNTech, 36 cases of Guillain-Barré syndrome were reported, the researchers said.

The findings suggest that the risk for the complication may be 20% higher with the Johnson & Johnson shot, they said.

"[We] found a small, increased risk of Guillain-Barré syndrome, a rare neurological disorder, during the three weeks after [Johnson & Johnson] vaccination (dose 1) but not after the mRNA COVID-vaccination," Dr. Nicola P. Klein, a co-author of the study, told UPI in an email.

"Individuals who choose to receive [Johnson & Johnson's] COVID-19 vaccine should be informed of the potential safety risks," said Klein, a senior research scientist at the Kaiser Permanente Northern California in Oakland.

The Centers for Disease Control and Prevention has "preferentially recommended" use of the mRNA COVID-19 vaccines from Moderna and Pfizer-BioNTech for primary and booster doses, she added.

Guillain-Barré syndrome causes rapid-onset muscle weakness as a result of the immune system attacking the peripheral nervous system in error, according to the CDC.

It has been associated with COVID-19, specifically "long COVID," or persistent viral symptoms, in previous studies, and has also been reported among recipients of the vaccines against the virus, particularly the Johnson & Johnson product, according to the Food and Drug Administration.

For this study, Klein and her colleagues analyzed side effect data for more than 8.8 million doses of the Pfizer-BioNTech vaccine, more than 5.8 million doses of the Moderna vaccine and more than 483,000 doses of the Johnson & Johnson vaccine.

They focused specifically on reports of Guillain-Barré syndrome, which can be disabling, they said.

Within three weeks of vaccine administration, there were six cases of Guillain-Barré syndrome reported for every 100,000 recipients of the Johnson & Johnson shot, the data showed.

For the Moderna and Pfizer-BioNTech vaccines, there were 1.3 cases of Guillain-Barré syndrome for every 100,000 doses administered.

"This study did not identify any specific group at increased risk for Guillain-Barré syndrome from the J&J vaccine," Klein said.