In 2016, the World Health Organization (WHO) revised its recommended dosing schedule for human papillomavirus (HPV) vaccination from three doses to two doses for adolescents ages 14 and under. Mothers of and health care providers for adolescent girls in five countries preferred the two-dose HPV vaccination schedule, according to new research published October 4 in Cancer Causes & Control.
Jessica Islam, a UNC Gillings School of Global Public Health doctoral candidate in the Department of Epidemiology, was lead author on the paper, “Acceptability of two- versus three-dose human papillomavirus vaccination schedule among providers and mothers of adolescent girls: A mixed-methods study in five countries.”
Other Gillings School authors on the paper include Nadja Vielot, PhD, alumna and now postdoctoral fellow in the Department of Family Medicine; Nicole Butera, doctoral candidate in the Department of Biostatistics; and Jennifer S. Smith, professor in the Department of Epidemiology. Smith is also a member at the UNC Lineberger Comprehensive Cancer Center.
Islam and her team examined data from five countries – Argentina, Malaysia, South Africa, South Korea and Spain – to investigate the acceptability of a two-dose versus three-dose HPV vaccination schedule among providers and mothers of adolescents in 2014, prior to the release of the updated recommended schedule. The authors identified potential cited advantages and disadvantages of the two-dose schedule compared to a three-dose schedule.
The team found that most adolescent providers and mothers preferred a two-dose over a three-dose schedule, citing lower cost and fewer clinic visits, as well as a greater likelihood that the vaccine series would be completed. However, both providers and mothers expressed some concerns regarding the safety and efficacy of a two-dose series, which is an opportunity for future public health education interventions.
“Now that the WHO recommends the two-dose HPV vaccine for adolescents under 15 years, it is important to ensure providers are equipped with the correct information regarding HPV vaccination’s efficacy and safety,” Islam said. “We found that providers expressed concerns regarding lower vaccine efficacy when using the two-dose compared to the three-dose HPV-vaccination schedule.”
Smith, senior author on the paper, said lessons learned from the study could inform future programmatic decisions as more countries adopt the two-dose HPV-vaccination schedule.
“Reducing from three to two doses may alleviate the logistical barriers to obtaining HPV vaccination in adolescents, lead to improved vaccination coverage, and ultimately lower rates of cervical and other HPV-associated cancers globally,” said Smith.
HPV is a common, sexually transmitted virus that has been linked to abnormal cell changes that can lead to cervical cancer. Administering HPV vaccination to individuals before sexual activity occurs greatly reduces the risk of HPV infection and associated cancers caused by HPV. It is recommended that adolescents receive the vaccine, with universal vaccination given in two doses, six to 12 months apart, at ages 11 or 12.