The relationship between nanny and employer is a family service contract. In the family service contract, the nanny should have a physical examination before providing family service and truthfully inform the employer of her physical condition. If she finds herself suffering from infectious diseases, she should take preventive measures. Once the nanny's infectious disease is transmitted to the employer, such disputes involve two legal relationships: tort liability and breach of contract liability.
Hiring a nanny is a big deal. You must observe the nanny's personality and habits. Don't worry too much about the nanny. Once something goes wrong, it's too late to regret it.
The nanny must have a detailed examination before going home, and there must be no infectious diseases in the new moon, otherwise it will be bad for the whole family to be infected.