Sunny Macer on Day 7
|Portrayed by||Christina Chang|
|First appearance||Day 3: 1:00 PM – 2:00 PM|
|Last appearance||Day 7: 7:00 AM – 8:00 AM|
 Day 3
Dr. Macer and her staff discover a corpse infected with a virus outside the NHS building with her name on it. After they isolated the body, she reveals that the virus is a specific type of highly lethal contagion due to the infection's marks on the body. She later determined the virus as the Cordilla virus.
She then briefs CTU: Los Angeles staff about the effects of the virus and her estimate on the casualty rate if the virus is exposed to the public.
When the virus was released into the Chandler Plaza Hotel, she and her team assisted with the situation. She tested Michelle Dessler, who was inside the building, for the virus. She later gave the results to Michelle, which revealed she was immune to the virus.
 Day 7
After Jack Bauer reported that the bio-weapon was leaked, Dr. Macer and her team arrived at the scene of the outbreak. At the scene, she tested Jack to see if he was infected. She later gave him the results, in which he tested positive, but was not contagious. She then went with him to the FBI building.
When Jack suffered a seizure, a symptom of the virus, Dr. Macer injected Jack with medicine that would mask the symptoms. She also have him a pack of syringes with more medicine. She then told him that a university was experimenting with a cure for the virus, thought there was only a small chance of success. For the treatment, Jack would need blood from a close relative, Macer suggested Jack's daughter. But, Jack quickly rejected the offer due to his strained relationship with his daughter and not having her involved in it. After Jack starts to forget things when talking with President Taylor, he sees Dr. Macer who says that memory loss is a symptom of the disease and that it can't be treated. She also says it may cause personality changes and hallucinations.