Scientists said Pfizer’s RSV vaccine for older adults should be monitored for Guillain-Barre, in an article published in the New England Journal of Medicine.

The FDA sees a potential risk and has asked Pfizer to conduct a safety study on Guillain-Barre after a potential approval, which the company said it would do.

RSV infections kill between 6,000 and 10,000 older adults every year and result in 60,000 to 120,000 hospitalizations, according to the CDC.

Pfizer said the FDA has accepted its RSV vaccine candidate for review under an expedited process that reduces the approval process by four months.