**Case Summary:**

**Patient Information:**
- Name: J.C.
- Age: 44 years old
- Gender: Male
- Occupation: Market vendor

**Chief Complaint:**
- Shortness of breath

**History of Present Illness:**
- Onset: 7 days prior to ER visit
- Initial Symptoms: High-grade fever, malaise, and non-productive cough
- Treatment Attempt: Anti-parasitic drugs, advised by a neighbor, ineffective
- Current Symptoms: Persistent fever and cough, shortness of breath, loss of taste

**Medical History:**
- Past Medical History: Unremarkable
- Family Medical History: Unremarkable
- Personal/Social History: Works daily at the market selling goods

**Physical Examination:**
- General: Conscious, coherent, oriented
- Vital Signs:
- Blood Pressure: 120/70 mmHg
- Cardiac Rate: 110 bpm
- Temperature: 38.8°C
- Oxygen Saturation on Room Air: 85%
- Skin: Unremarkable
- Head: Unremarkable
- Eyes: Pink palpebral conjunctivae, anicteric sclerae
- Ears: Auricles symmetrical, non-tender; patent canals, intact tympanic membrane
- Nose: Symmetrical, with alar flaring; patent vestibules
- Mouth and Oral Cavity: Unremarkable
- Neck: Supple, symmetrical, no masses or lymphadenopathy
- Lungs/Chest: Symmetrical expansion, crackles from mid to base on auscultation
- Heart: Tachycardic, regular rhythm, no heaves, thrusts, or thrills
- Abdomen: Unremarkable
- Extremities: Unremarkable

**Laboratory Results:**
- COVID-19 Antigen: Positive
- COVID-19 PCR: Positive
- SARS-CoV-2 IgG/IgM: Negative

**Questions:**

1. In the physical examination, why does the patient have an increased cardiac rate?
2. Assuming 3 months post-recovery, the patient's SARS-CoV-2 IgG shows a positive result. What does this imply?