Holidaymakers have been given fresh warnings to ensure they are vaccinated against measles after it emerged European cases have reached an eight-year high.
The World Health Organisation (WHO) warned the number of cases of the highly infectious disease during 2018 have already outstripped any year since 2010.
Across Europe there were more than 41,000 measles cases recorded during the first six months of 2018, including 37 deaths.
The WHO said the highest annual total for measles cases since 2010 was recorded in 2017 when 23,927 cases were identified.
The global health body said France, Georgia, Greece, Italy, Russia, Serbia and Ukraine have had more than 1,000 cases each so far in 2018.
Ukraine has been the hardest hit with over 23,000 people affected, it said.
Meanwhile, Public Health England (PHE) issued further warnings for people who are travelling to countries with outbreaks.
It said people should ensure they are up to date with their measles, bumps and rubella (MMR) vaccination before travel.
Meanwhile, those who are starting university or attending festivals should also make sure they are protected.
Figures from the health body show that from January 1 to August 6 there were 807 laboratory confirmed measles cases.
PHE said many cases have been linked to ongoing outbreaks in Europe.
It said 58% of confirmed cases have been among children aged 15 and younger, who missed out on their MMR vaccine when they were younger.
Dr Mary Ramsay, head of immunisation at PHE, said: "We have seen a number of measles outbreaks in England which are linked to ongoing large outbreaks in Europe.
"The majority of cases we are seeing are in teenagers and young adults who missed out on their MMR vaccine when they were children.
"Anyone who missed out on their MMR vaccine in the past or are unsure if they had two doses should contact their GP practice to catch-up.
"We would encourage people to ensure they are up to date with their MMR vaccine before travelling to countries with ongoing measles outbreaks, heading to large gatherings such as festivals, or before starting university."
Dr Zsuzsanna Jakab, WHO regional director for Europe, added: "Following the decade's lowest number of cases in 2016, we are seeing a dramatic increase in infections and extended outbreaks.
"We call on all countries to immediately implement broad, context-appropriate measures to stop further spread of this disease."
Measles is a highly infectious viral illness and can be deadly in some cases.
Early signs of illness include cold-like symptoms, sore eyes that may be sensitive to light, fever and small greyish-white spots on the inside of the cheeks.
A few days later a blotchy red-brown rash will appear, usually starting on the head or neck.
Commenting on the WHO figures, Dr Pauline Paterson, co-director of the Vaccine Confidence Project team at the London School of Hygiene & Tropical Medicine, said: "With a vaccine-preventable disease, one case is one too many, and the number of measles cases so far this year is astounding.
"Measles is a highly infectious disease that can spread rapidly and lead to serious complications - a very high vaccination coverage of 95% is needed for community protection.
"If the coverage dips below this in certain regions, measles cases can spread and outbreaks can and are occurring.
"While most people vaccinate, some individuals do not. The reasons for non-vaccination can vary from issues of vaccine access, a lack of perceived need to vaccinate, and concerns around the safety of vaccination - in 2016 the Vaccine Confidence Project found that the European region was the most sceptical in the world on vaccine safety.
"Vaccines work. If measles is to be eliminated, we must continue to further our understanding of the underlying reasons for non-vaccination and to address them with effective evidence-based interventions."