A 32-year-old woman who is 28 weeks pregnant presents to the Emergency Department with concerns about chickenpox exposure. She was in close contact with her 4-year-old nephew who developed chickenpox rash 2 days ago. She has is unsure if she had chickenpox as a child, and has not had the vaccine.

Past Medical History:

• Gestational diabetes (diet-controlled)
• Mild asthma
• No known allergies

Medications:

• Prenatal vitamins
• Salbutamol inhaler PRN

Vital Signs:

• Temperature: 37.2°C
• Blood Pressure: 118/72 mmHg
• Heart Rate: 82/min
• Respiratory Rate: 16/min
• O2 Saturation: 98% on room air

General Examination:

• Alert and oriented
• No rash present
• Chest: Clear breath sounds bilaterally
• Heart: Regular rhythm, no murmurs
• Abdomen: Gravid uterus consistent with gestational age, foetal movements felt
• No lymphadenopathy

What is the most appropriate immediate management for this patient?