Figures due out today will show whether the measles outbreak centred on the Swansea area is continuing to grow.
Figures earlier in the week showed 22 new cases of measles across the area since a week last Thursday, and another 32 in other parts of Wales.
2013 is expected to be the worst year for measles in the UK for the past two decades. Read more about the illness and how it is treated.
If the Government's top adviser on immunisation thinks the risk of an emergency in England is a possibility, I believe him.