After several diagnoses over several weeks, Alberta health officials have declared measles outbreaks in Edmonton, Calgary and central Alberta.

Alberta Health Services says nine cases have been diagnosed in the Calgary area, six in the Edmonton area, and seven in the central part of the province.

The outbreak declaration allows babies over six months of age in those areas to receive a first dose of measles vaccines. Normally, the first dose is given around the child’s first birthday.

The early vaccine is considered an additional dose, and infants who receive it will still be required to receive the two routinely recommended measles vaccine doses at 12 months and between four and six years of age.

"This additional early dose will provide short-term added protection to infants six months to less than 12 months of age, who are otherwise vulnerable during this time of increased risk of exposure to disease," the health ministry said in a statement Tuesday evening.

The health agency is also advising that children over four years of age to receive their second dose of vaccine as soon as possible. Normally, preschoolers are advised to receive the vaccine anytime between four and six years of age.

"During an outbreak, ensuring children attending daycares/day homes and schools have received this second dose as soon as possible will reduce the likelihood of these children being excluded from these locations following exposure to disease," Alberta Health said.

There have been 22 confirmed cases of measles in Alberta this year.

Anyone born after 1970 needs two doses of the measles vaccine to be protected. Alberta Health continues to advise all Albertans to ensure they are up-to-date on all immunizations.

Measles is considered one of the most contagious diseases and there is no specific treatment for it. Immunization is considered the best protection.