Of the over 12 million Johnson & Johnson vaccines administered, 100 cases of Guillain-Barré syndrome (GBS) were reported within 42 days after vaccination. Most cases were found in men aged 50 and older.

Post-vaccination GBS cases are rare, but higher than expected, the CDC panel said. The Federal Food and Drug Administration (FDA) on July 12 added a warning about GBS to its fact sheets about the Johnson & Johnson vaccine. The CDC will follow suit.

The Advisory Committee on Immunization Practices (ACIP) continues to recommend that people with histories of GBS get any of the FDA-authorized COVID-19 vaccines, but advise to first talk to a doctor about mRNA vaccine options. Experts also emphasize the importance of having a single-dose vaccine in communities with low vaccination rates.

Hannah Rosenblum, MD, a member of the Epidemic Intelligence Service with the CDC, said at the Thursday meeting that the benefits of Johnson & Johnson vaccine and the mRNA vaccines in preventing COVID-19 hospitalizations and deaths greatly outweigh the risks of GBS.

Rosenblum’s statements were backed by Sarah Mbaeyi MD, MPH, a CDC medical officer, who pointed to the importance of the Johnson & Johnson vaccine in “reaching disproportionately affected populations and for achieving vaccine equity.”

She added that the known benefits of the authorized COVID-19 vaccines are “unequivocal.”

Johnson & Johnson representatives made an unexpected appearance at the meeting, defending the benefits of the Janssen vaccine. Joanne Waldstreicher, MD, the company’s chief medical officer, stressed that “multiple vaccine options are needed in the global public health toolbox” as the pandemic continues to evolve.

“For many parts of the globe, the single dose and easily transportable vaccine is critical,” Waldstreicher said.

A Johnson & Johnson preprint study showed that the Janssen vaccine can offer immunity for at least eight months against circulating variants.

Another recent study suggested that vaccines like Johnson & Johnson’s are less effective against variants like Delta and Lambda.

Jason Diaz, PhD, an assistant professor of integrated science, business, and technology at La Salle University, says people should be critical when looking at either study, because they are lab-based and have yet to be peer reviewed.

“It’s possible that the J&J vaccine is going to take a bigger hit than the mRNA vaccines against Delta, or maybe it won’t,” Diaz tells Verywell. “I haven’t seen convincing data that tells me one way or another where that’s going to land.”

Members of the ACIP committee had varying views on Johnson & Johnson’s continued use at the Thursday meeting.

Pablo J. Sanchez, MD, a professor of pediatrics at The Ohio State University, said while he supported the use of all the approved vaccines, he recommended mRNA vaccines over the Johnson & Johnson vaccine. Sarah S. Long, MD, attending physician of infectious diseases at St. Christopher’s Hospital for Children, argued that the same recommendation could be made in favor of the Johnson & Johnson vaccine due to the mRNA vaccine’s connection with rare cases of Myocarditis.

“The burden should be on the vaccinators that the patient be made aware of the complications, and the patient be made aware of other vaccines that potentially could be used,” Long said.

Others supported the wide use of all three FDA-authorized vaccines, noting the convenience of the single-dose vaccine particularly in unvaccinated hotspots.

José R. Romero, MD, Arkansas’ secretary of health, said a single-dose vaccine is crucial for the state’s COVID-19 strategy.

“There are clearly individuals in my state that will not come back for a second dose,” he said.

Romero added that Arkansas’ cases have more than doubled in two weeks, with an increasing death rate. As of July 21, the Arkansas Department of Health is reporting 11,903 active COVID-19 cases, at an increase of 428 new cases and 13 new deaths from the day before.

“I think it’s important that we have available to us all three vaccines at this time for the public to use as they see appropriate, and that they be allowed to choose this,” Romero said.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.