Dutch regulators have issued new guidance urging parents and doctors to vaccinate boys against the human papilloma virus.

For more than a decade, authorities have recommended that girls receive the vaccine around age 12 or 13 but rates have dropped in recent years, and the country’s Health Council is now urging the ministry of health to recommend vaccines for boys and girls beginning around age nine.

The council also recommends that the vaccines be available for adults up to the age of 26 to help increase herd immunity.