British measles outbreak called the worst since the introduction of the MMR vaccine

The U.K. Health Protection Agency recently called the measles outbreak in Merseyside County the worst in the region since the introduction of the MMR vaccine.

There have been a total of 113 confirmed cases in the area and another 43 potential cases. Twenty-eight people have been admitted to the hospital for treatment, according to the BBC.

Three measles cases, two adults and one child, were considered critical, but the patients have since recovered.

The HPA has urged parents to make sure that their children are fully vaccinated.

The agency declared the situation an outbreak last month after six people were admitted to the hospital for treatment. Most of the cases were reported in children who had not been given the MMR vaccine, or in babies too young for the vaccination.

Teenagers and young adults who were not vaccinated as children account for approximately 29 of the confirmed cases, while 27 of the confirmed cases are in children under the age of 13 months.

"Measles is highly infectious and anyone who has not previously been vaccinated is at risk when it gets into a community, as it has done here," Dr. Roberto Vivancos, a specialist with the Chesire and Merseyside Health Protection Unit, said, the BBC reports. "In this outbreak we have seen measles spreading amongst unvaccinated children, teenagers and young adults and affecting infants and toddlers who are too young to be vaccinated."