The Irish Cancer Society is warning parents to beware of misleading information about the HPV vaccine.
Health professionals are said to be concerned about a significant drop in the numbers getting the vaccination.
It's reported that just 50% of girls have taken up the offer of the first dose, down from 87% two years ago.
The Irish Cancer Society says parents are being frightened by fake news that the vaccine has serious long term side effects.
Dr. Brenda Corcoran from the National Immunisation Office, says they’ve got spread the word the vaccine is safe and effective.
"It is a challenge to all of us to counteract alternative facts which parents are reading and parents are believing.
"Unfortunately they are not true. We have to be more involved in social media, we have to be more involved in ways that parents connect with each other to get the information out through whatever means."