Date: 202005
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Aircraft: Large Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Airspace: Class B ZZZ
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Communication Breakdown; Distraction
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Illness / Injury
Detector: Person Flight Attendant
When detected: In-flight
Result: General Physical Injury / Incapacitation
Contributing factors: Environment - Non Weather Related; Human Factors
Primary problem: Human Factors

Narrative: After forward entry door closed; I was advised by #1 FA that we had a sick passenger on board; and a CSM had okayed travel by the passenger.  At the same time; I got a call from the #4 FA advising me that the passenger was acting sick/nauseous and disoriented and was causing a lot of concern with the other passengers; who were concerned about their safety and health.  This was the first time I was informed of the passenger issue; CSM never consulted or briefed me.  We had no way to isolate [the] ill passenger.  Contacted operations to have CSM return to aircraft.Was told that passenger had been denied boarding on a previous flight; and paramedics had attended to passenger and okayed the travel; but there was no record of this or witnesses; just what the passenger claimed.  I asked CSM if the passenger's temperature had been taken; it had not.  I asked that be done; but they had to get a thermometer from outside security.While waiting for the thermometer; and after further consultation with the FA's concerning their interaction with the passenger; as well as increasing concern by other passengers about traveling with a passenger that was exhibiting obvious signs of illness of some type; I decided to have the passenger removed from the flight to ensure the safety of my crew and passengers because of the behavior and symptoms being exhibited by the passenger in question and the unknown cause of illness. In my opinion; poor screening by gate and CSM personal; desire to not deal with an issue and try to push it off on the crew; hoping to let the problem be handled by the flight crew and not dealt with by the gate personnel.In these times during a national health pandemic; we need to be more cautious and err on the side of safety for the majority of the passengers and crew rather than avoiding making a decision that affects just one passenger or crew.  We; as an airline; including gate/CSM personnel; need to treat these situations as if the potentially ill passenger is going to go back and sit down next to one of our family or loved ones.  Also; we need to consider the optics of allowing a visibly ill passenger onto an aircraft with a public that has a heightened awareness and concern about the health conditions of other passengers.  Also; the CSM and agents need to get the Captain in the loop about things that are going on his/her aircraft.  I am absolutely floored that the first I heard about this was by my flight attendants after the agent had given me the final check before closing the door.  I hate to say it; but this was yet another example of the degradation of not only Captain's authority; but also professional respect for the Captain and the entire flight crew.




Synopsis: Air carrier Captain reported having to remove a passenger showing symptoms of illness.