Hundreds of girls in West Sussex were not fully vaccinated against the potentially cancer-causing HPV virus last year, new figures show.
Girls in England are offered free HPV jabs at school during years eight and nine, when they are aged between 12 and 14.
However, Public Health England figures show just 84.1 per cent of girls in West Sussex were given the recommended two doses of the vaccine by the end of year nine in 2017-18.
This was above the national average, but 719 girls were still left unprotected.
The HPV vaccination protects against the human papilloma virus, which is responsible for more than 99 per cent of cervical cancer cases as well as some other rarer cancers.
Cervical cancer charity Jo’s Trust said it was important ‘not to get complacent’ despite overall coverage remaining high.
Robert Music, chief executive of Jo’s Trust, said: “The vaccine is one of the best tools we have for preventing the disease.
“It prevents seven out of ten cases of cervical cancer, so we absolutely encourage all young women to take it up when offered.”
According to the NHS, the vaccine works best when girls receive it before they become sexually active.
HPV can be spread through any kind of skin-to-skin contact, as well as through sexual intercourse.
England has seen declining rates of HPV vaccination over recent years, falling from 86.7 per cent in 2013-14 to 83.8 per cent last year.
Public Health England has suggested the decline could be due to an increased focus on flu vaccinations taking up the resources of school health teams in some parts of the country.
However, a spokeswoman said the immunisation programme was still ‘one of the most successful around the world’ and had helped protect millions of girls since its launch in 2008.
Cancer Research UK said it expects to see a drop in cases of cervical cancer over the coming years.
Katie Patrick from the charity said: “The first group of girls to be vaccinated are now approaching the age where cervical cancer risk increases.
“It will be exciting to see the benefits of the vaccine.”
The minimum vaccination target set by Public Health England for local areas is 80 per cent, but local teams are encouraged to aim for 90 per cent or above.
Last year coverage for year nines ranged from a low of 65.3 per cent in London’s Hammersmith and Fulham to a high of 94.3 per cent in North Yorkshire and Tameside, near Manchester.
Mr Music said more insights were needed to understand why there are disparities between local authorities.
He said: “It is key that coverage remains high and so educating girls and parents about the role of the vaccine and breaking down any myths surrounding it is vital.”
HPV vaccines will also be rolled out to 12 and 13-year-old boys from next September.
Dr Mary Ramsay, head of immunisations at Public Health England, said this would help prevent more cases of HPV-related cancers such as head, neck and ano-genital cancers.
Girls remain eligible for the vaccine until their 18th birthday and should speak to their GP or school nurse if they have missed one of their jabs, she added.
• Report by Harriet Clugston, data reporter