Factors Influencing Completion of Multidose Vaccine Schedules in Adolescents

A Systematic Review

K. E. Gallagher; E. Kadokura; L. O. Eckert; S. Miyake; S. Mounier-Jack; M. Aldea; D. A. Ross; D. Watson-Jones

Disclosures

BMC Public Health. 2016;16(172) 

In This Article

Background

In the past decade there has been an increase in the number of new vaccines licensed worldwide[1,2] and in the accessible funding for vaccine introduction to low-resource settings through the founding of Gavi, The Vaccine Alliance, in 2000.[3] Multi-dose vaccines in the WHO recommended immunization schedule for adolescents are listed in Table 1; WHO defines adolescence as age 10–19 years inclusive. National vaccine schedules can depart from WHO recommendations, e.g. 2 doses of hepatitis A and meningococcal conjugate vaccines (MCV4) are offered to adolescents in the USA.[4] Although recommended for administration at birth, hepatitis B vaccine (HBV) is routinely offered to older children and adolescents if not previously immunized.[5] In settings where varicella is seen as a public health priority WHO recommends 2 doses of varicella vaccine, with the first dose at 12–18 months and up to 4 month interval between doses.[6,7] The most recently licensed multi-dose vaccines are the human papillomavirus (HPV) vaccines. In 2014, HPV vaccine recommendations were revised by WHO SAGE from a schedule of 3 doses,[8] to 2 doses at a 6 month interval in girls less than or equal to 15 years of age[9,10] based on evidence of non-inferior immunogenicity.[11,12]

At present, evidence suggests multiple doses of HBV, HPV, and varicella vaccines are needed for efficacious protection against disease in adolescents.[5,9,13,14] However; completion of the vaccine dose series, defined as receipt of the final dose within 1 year of the first dose, has proven challenging in some settings. Completion rates of HPV vaccine were lower than 30 % in the first years of introduction in the USA.[15,16] Addressing specific difficulties in administering vaccines to adolescents will be invaluable for implementation of future adolescent vaccines and further developing adolescent health services.

The currently available reviews of factors influencing completion focus solely on selected developed countries,[1,17–19] have non-systematic searches[20,21] or need updating.[22] This systematic review describes factors which have been investigated for their effect on multi-dose vaccine adherence in adolescents to aid development of interventions to improve adherence.

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