Since the beginning of the year there have been 440 confirmed measles cases in England, with London (164), the South East (86), West Midlands (78), South West (42) and West Yorkshire (37) reporting the most cases.
The increase in measles circulation is mainly associated with travel to and from Europe where there are large ongoing measles outbreaks, says Public Health England.
Young people and adults aged 15 and over who missed out on MMR vaccine when they were younger and some under-vaccinated communities have been particularly affected.
Measles is a highly infectious viral illness that can sometimes lead to serious complications and can be fatal in very rare cases.
Anyone who has not received 2 doses of MMR vaccine is at risk, but young people in environments with close mixing such as festivals are more at risk, as well as unvaccinated people travelling to Romania and Italy, where there are currently large outbreaks.
Anyone planning to travel to Europe should check NaTHNaC travel health advice.