Study shows measles vaccine more effective if administered later

A second measles vaccine study conducted by Canadian researchers questions the timing at which the vaccine is administered to children.

The new research demonstrated that the vaccine was more effective in teenagers who received their first dose of the two dose series at 15 months rather than at 12 months, according to

Those who received the first dose of the vaccine at 12 months were six times more likely to contract the highly contagious illness.

The study was conducted after a large measles outbreak occurred in Quebec in 2011. During that outbreak, a number of children who were assumed to be protected from the illness were nevertheless infected.

Lead author Dr. Gaston De Serres of Quebec's provincial public health agency said that he does not believe the Canadian government will be willing to change the dosage schedule on the basis of the study.

"For Canada I would probably say that at this time we will not change the schedule," De Serres said, reports. "We need to follow up with more studies."

Jane Seward, a measles expert with the U.S. Centers for Disease Control, said the goal of public health programs needs to be to vaccinate children as soon as possible while ensuring the vaccine's effectiveness.

"It's a balance between getting the first dose as early as possible to decrease deaths and as late as possible to get the best immune response," Seward said, reports.