Not enough Scottish children are receiving MMR shots, say official figures.
Statistics for 2006 show that only 92.1 per cent of two-year-olds were given the jab, which protects against measles, mumps and rubella, as against the national target of 95 per cent.
Yet, this is an increase from the previous year, when the figure was 89.9 per cent.
MMR vaccines were introduced in 1988, but levels of uptake began to decline after 1998 when a controversial study linking the triple vaccine to autism began doing the rounds.
After widespread public information offensive from health professionals vouching for its safety, uptake is now increasing again.
Other figures show that the target immunization rate of 95 per cent was met for all other diseases last year, with 97.9 per cent of two-year-olds protected against diphtheria, tetanus and polio, 97.8 per cent given the whooping cough vaccine, 97.6 per cent vaccinated against haemophilus influenza type B and 97 per cent immunized against meningitis C.
Conservative health spokeswoman Dr Nanette Milne was reported arguing that the 95% percent target may not be achieved for some considerable time.
"Given the number of parents refusing to have their children vaccinated with MMR, and the worrying number choosing not to vaccinate their children at all, alternative action must be taken", she said.
"At present, only those who can afford to pay for the single vaccine have the choice - that is wrong.
"This choice must be extended to the parents of every child by placing the single vaccine on the NHS. It is not right that only the better off can afford to choose the treatment available to their children", Milne added.
MMR uptake was highest in Dumfries and Galloway and lowest in Orkney, where only 84.4 per cent of that age group was immunized.
An Executive spokeswoman welcomed the increase in uptake as a testament to the endeavors of health professionals, and said that ministers were working with experts to provide parents with information on the MMR vaccine.