Yes, it is safe for you to go office. The most important thing is to inform the responsible person (HR department for e.g.) that the sick person should be discreetly asked to take time off. In the meantime take proper preventive measures to protect yourself such as frequent hand washing, using alcohol based hand rubs and maintaining distance from sick persons as far as possible. Watch out for flu
symptoms and see a doctor if you develop symptoms suggestive of flu.