Maybe the FDNY’s top doc should take a refresher course on how to properly administer a flu shot.

The department posted photos on Twitter last week showing its esteemed Chief Medical Officer, Dr. David Prezant, giving a flu shot to Fire Commissioner Daniel Nigro and two other department brass — with his bare hands.

But Prezant wasn’t following FDNY protocol: He wasn’t wearing gloves, which is always important when injecting patients — but especially during the COVID-19 pandemic.

What’s worse, Prezant had a small cut on his thumb, which is seen pressing against Nigro’s shoulder.

Photos also show Prezant vaccinating First Deputy Commissioner Laura Kavanagh and Chief of Department John Sudnik.

FDNY spokesman Frank Dwyer noted that Prezant, as well as his patients, importantly wore masks while they were doing the vaccinations.

But, Dwyer added, “The doctor did acknowledge that gloves should have been worn in this instance.”

The photo-ops aimed to promote the FDNY’s Operation BioPOD, an emergency-preparedness initiative. All department personnel are given the option to receive the flu vaccine while they are on duty.