The price of life-saving vaccines has skyrocketed leaving some countries struggling to fully immunise children, Medecins Sans Frontieres warns.
A report by the charity says there has been a 68-fold increase in prices between 2001 and 2014.
It accused the pharmaceutical industry of overcharging and highlighted cases where rich western countries were getting a better rate than poor ones.
Industry said its pricing reflected the cost of manufacture.
The medical charity's report says prices are now "prohibitively high" and were "calling into question the sustainability of immunisation programmes".
The document "The Right Shot" says the number of vaccines offered has doubled since 2001, but the price has increased even more so.
In 2001, it cost $0.67 (£0.44) to vaccinate against tuberculosis, measles, diphtheria, tetanus, whooping cough and polio.
Since then rubella, hepatitis B, Haemophilus influenzae type b, pneumococcal diseases, rotavirus and the human papillomavirus (HPV) vaccines have been added to vaccination programmes.
But the cost has leapt to $45.59 (£30.07) per child.