In this articlePFEGSK-GBGSKFollow your favorite stocksCREATE FREE ACCOUNT This 1981 photo provided by the Centers for Disease Control and Prevention (CDC) shows an electron micrograph of Respiratory Syncytial Virus, also known as RSV.CDC via AP The Food and Drug Administration sees a possible risk of Guillain-Barre syndrome with Pfizer's RSV vaccine for older adults and