Nannies are seldom sick. Even when poorly most will come in and take it easy for a day or so as long as you are understanding about it. If you don’t want your nanny turning up to work with a bad cold you need to make that clear at the start. Many nannies can’t actually afford the time off every time they have a sniffle, and your children have probably already been exposed to the germs.
If a nanny is off sick, or needs to have scheduled surgery, then you will need to look at the arrangements you made for sick pay in your contract. Most nanny contracts specific Statutory Sick Pay (SSP) only, which kicks in after 3 days of absence. Some more generous contracts pay those first 3 days at the full rate no matter what, other contracts give a fixed number of paid sick days per year and once those are gone they’re gone. Even if you contract says you only pay SSP you can still make an exception and pay half or full pay, for example if you’ve asked your nanny not to work because you want to avoid your child getting sick or if your nanny is off sick with something they caught from your child.
You cannot ask your nanny to make up hours that they were ill. Your nanny does have a right to be off sick to rest and recover and return to their job when they are better.
If your nanny is off work for an extended period of time with a serious illness or injury you will need to seek specialist advice.
Is your nanny pregnant? Special rules around sickness during pregnancy apply.