The HPV vaccine given to schoolgirls to reduce their risk of cervical cancer has been given the all-clear by a European safety watchdog.
There is no evidence of a causal link between the HPV vaccine and abnormal symptoms such as chronic pain and seizures, it said.
The findings were released in a review carried out by the European Medicines Agency following claims by the parents of teenage girls in several countries, including Ireland, that their daughters developed severe symptoms after getting the vaccine.
A group Regret.ie was set up here with 100 families who are searching for answers to their daughters' conditions, which include chronic fatigue and fits.
The investigations arm of the European Medicines Agency looked at two conditions, complex regional pain syndrome (CRPS) and postural orthostatic tachycardia syndrome (POTS) in young women who had been given the human papillomavirus (HPV) vaccines.
It concluded that "the evidence does not support a causal link" between the vaccines, including Gardasil which is administered in Ireland.
"Therefore there is no reason to change the way the vaccines are used or amend the current product information."
CRPS is a chronic pain syndrome affecting a limb, while POTS is a condition where the heart rate increases abnormally on sitting or standing up, together with symptoms such as dizziness, fainting and weakness, as well as headache, aches and pains, nausea and fatigue.
"In some patients they can severely affect the quality of life. The syndromes are recognised to occur in the general population, including adolescents, regardless of vaccination," it said.
It said it thoroughly reviewed published research, data from clinical trials and reports of suspected side effects from patients and healthcare professionals, as well as data supplied by member states including Ireland.
It also consulted a group of leading experts in the field, and took into account detailed information received from a number of patient groups that also highlighted the impact these syndromes can have on patients and families.
Symptoms of CRPS and POTS may overlap with other conditions, making diagnosis difficult in both the general population and vaccinated individuals.
However, available estimates suggest that in the general population around 150 girls and young women per million aged 10 to 19 years may develop CRPS each year, and at least 150 girls and young women per million may develop POTS each year,it said.
The Irish medicines' watchdog, the Health Products Regulatory Authority, said it will continue to monitor the vaccine's safety.
It has been given to 644,161 girls here and on the basis of the review will not be changing the recommendations on how it should be administered. A spokeswoman said: "There is no reason to change the way the vaccines are used."