Assessment of on-time vaccination coverage in population subgroups: A record linkage cohort study

Abstract

Reported infant vaccination coverage at age 12 months in Australia is >90%. On-time coverage of the 2-4-6 month schedule and coverage in specific populations is rarely reported. We conducted a population-based cohort study of 1.9 million Australian births, 1996-2012, combining individual birth and perinatal records with immunisation records through probabilistic linkage. We assessed on-time coverage across 13 demographic and perinatal characteristics of diphtheria-tetanus-pertussis vaccines (DTP) defined as vaccination 14 days prior to the scheduled due date, to 30 days afterwards. On-time DTP vaccination coverage in non-Aboriginal infants was 88.1% for the 2-month dose, 82.0% for 4-month dose, and 76.7% for 6-month dose; 3-dose coverage was 91.3% when assessed at 12 months. On-time DTP coverage for Aboriginal infants was 77.0%, 66.5%, and 61.0% for the 2-4-6 month dose; 3-dose coverage at 12 months was 79.3%. Appreciable differences in on-time coverage were observed across population subgroups. On-time coverage in non-Aboriginal infants born to mothers with ≥3 previous pregnancies was 62.5% for the 6-month dose (47.9% for Aboriginal infants); up to 23.5 percentage points lower than for first-borns. Infants born to mothers who smoked during pregnancy had coverage 8.7-10.3 percentage points lower than infants born to non-smoking mothers for the 4- and 6-month dose. A linear relationship was apparent between increasing socio-economic disadvantage and decreasing on-time coverage. On-time coverage of the 2-4-6 month schedule is only 50-60% across specific population subgroups representing a significant avoidable public health risk. Aboriginal infants, multiparous mothers, and those who are socio-economically disadvantaged are key groups most likely to benefit from targeted programs addressing vaccine timeliness.

Associated Factors for Dropout of First Vs Third Doses of Diphtheria Tetanus Pertussis (DPT) Vaccination in Nepal

“…Regarding the tobacco consumption, those mothers who did not consume any type of tobacco had a lower dropout than the tobacco user. Smoking and vaccination status is consistent with other studies [33,[39][40][41]. A study reported that smoking mothers are likely to start immunization 55.6 days after the schedule [42].…”

Australian Aboriginal children have higher hospitalization rates for otitis media but lower surgical procedures than non-Aboriginal children: A record linkage population-based cohort study

“…The introduction of PCV for Aboriginal children in 2001 may have contributed to the ongoing decline in hospitalization rates in the Aboriginal population (though coverage was low at 45–60%) but does not explain the contemporaneous decline in non-Aboriginal children as herd immunity would have been limited prior to the introduction of a national universal PCV program in 2005. When the universal program began, on-time receipt of 7vPCV was 78% for non-Aboriginal children [25]. Pneumococcal serotype or pathogen replacement with non-typeable Haemophilus influenzae following universal introduction of 7vPCV [26] may in part explain the lack of further reduction in OM hospitalization after 2005.…”

Retrospective Case-Control Study of 2017 G2P[4] Rotavirus Epidemic in Rural and Remote Australia

“…In practice, this limits opportunity to complete the full vaccination schedule and eliminates the possibility of catch-up of missed vaccinations in later childhood [ 25 ]. Delayed and/or incomplete vaccination is more common among Australian Aboriginal children [ 27 ] and in one observational study, two-dose DTPa coverage increased by a further 16% after the upper age limit of rotavirus vaccine administration (from 75% to 91% in Aboriginal infants), whereas two-dose rotavirus vaccine coverage increased by only 3% (from 75% to 78% in Aboriginal infants) [ 28 ]. This suggests that relaxing the upper age restrictions for rotavirus vaccines, as recommended by WHO for countries with high rotavirus burden [ 3 ], could be considered as a strategy for improving vaccine uptake and schedule completion.…”