Harvard College, Cambridge, MA, USA.
Departments of Global Health and Population, Boston, MA, USA.
BMC Infect Dis. 2019 Feb 26;19(1):188. doi: 10.1186/s12879-019-3828-3.
Delayed vaccination increases the time infants are at risk for acquiring vaccine-preventable diseases. Factors associated with incomplete vaccination are relatively well characterized in resource-limited settings; however, few studies have assessed immunization timeliness.
We conducted a prospective cohort study examining Diphtheria-Tetanus-Pertussis (DTP) vaccination timing among newborns enrolled in a Neonatal Vitamin A supplementation trial (NEOVITA) conducted in urban Dar es Salaam (n = 11,189) and rural Morogoro Region (n = 19,767), Tanzania. We used log-binomial models to assess the relationship of demographic, socioeconomic, healthcare access, and birth characteristics with late or incomplete DTP1 and DTP3 immunization.
The proportion of infants with either delayed or incomplete vaccination was similar in Dar es Salaam (DTP1 11.5% and DTP3 16.0%) and Morogoro (DTP1 9.2% and DTP3 17.3%); however, the determinants of delayed or incomplete vaccination as well as their magnitude of association differed by setting. Both maternal and paternal education were more strongly associated with vaccination status in rural Morogoro region as compared to Dar es Salaam (p-values for heterogeneity < 0.05). Infants in Morogoro who had fathers and mothers with no education had 36% (95% CI: 22-52%) and 22% (95% CI: 10-34%) increased risk of delayed or incomplete DTP3 vaccination as compared to those with primary school education, respectively. In Dar es Salaam, mothers who attended their first antenatal care (ANC) visit in the 3rd trimester had 1.55 (95% CI: 1.36-1.78) times the risk of delayed or not received vaccination as compared to those with a 2nd trimester booking, while there was no relationship in Morogoro. In rural Morogoro, infants born at home had 17% (95% CI: 8-27%) increased risk for delayed or no receipt of DTP3 vaccination. In both settings, younger maternal age and poorer households were at increased risk for delayed or incomplete vaccination.
We found some risk factors for delayed and incomplete vaccination were shared between urban and rural Tanzania; however, we found several context-specific risk factors as well as determinants that differed in their magnitude of risk between contexts. Immunization programs should be tailored to address context-specific barriers and enablers to improve timely and complete vaccination.
延迟接种会增加婴儿感染可通过疫苗预防的疾病的风险。在资源有限的环境中，与不完全接种相关的因素已得到较好的描述；然而，很少有研究评估免疫及时性。
我们进行了一项前瞻性队列研究，在坦桑尼亚城市达累斯萨拉姆（n=11189）和农村莫罗戈罗地区（n=19767）开展的新生儿维生素 A 补充试验（NEOVITA）中，研究了白喉-破伤风-百日咳（DTP）疫苗接种时间。我们使用对数二项式模型来评估人口统计学、社会经济、医疗保健获取和出生特征与 DTP1 和 DTP3 免疫延迟或不完全的关系。
在达累斯萨拉姆（DTP1 为 11.5%，DTP3 为 16.0%）和莫罗戈罗（DTP1 为 9.2%，DTP3 为 17.3%），延迟或不完全接种的婴儿比例相似；然而，延迟或不完全接种的决定因素及其关联的程度因环境而异。与达累斯萨拉姆相比，母亲和父亲的教育程度与农村莫罗戈罗地区的疫苗接种状况更为密切相关（异质性 p 值<0.05）。在莫罗戈罗，父亲和母亲均未受过教育的婴儿，与接受过小学教育的婴儿相比，DTP3 疫苗接种延迟或未接种的风险分别增加了 36%（95%CI：22-52%）和 22%（95%CI：10-34%）。在达累斯萨拉姆，首次产前检查（ANC）在 3 个月时就诊的母亲，与在第 2 个月就诊的母亲相比，DTP 疫苗接种延迟或未接种的风险增加了 1.55 倍（95%CI：1.36-1.78），而在莫罗戈罗则没有这种关系。在农村莫罗戈罗，在家中出生的婴儿，DTP3 疫苗接种延迟或未接种的风险增加了 17%（95%CI：8-27%）。在两个环境中，母亲年龄较小和家庭贫困的婴儿，接种疫苗延迟或不完全的风险增加。
我们发现，坦桑尼亚城乡之间存在一些延迟和不完全接种的共同风险因素；然而，我们也发现了一些特定于背景的风险因素，以及在两个环境中风险程度不同的决定因素。免疫规划应根据具体情况调整，以解决具体的障碍和促进因素，从而提高及时和完全接种的效果。
