Table 1 Association between influenza vaccination and SES, by single-measure SES
Study; Country | SES Concept (Level of SES measure) | Description SES measure | Adjusted mediating factorsa | Data source; Data type (Year collected) | Results |
|---|---|---|---|---|---|
Education (n = 6; 3 positive associations, 1 negative association, 2 no association) | |||||
 Barbadoro 2013 [13]; Italy | Education (Individual) | Level of education level (low, medium, high, 3-yr university degree, more than 4 years university degree, post-graduate) | Sociodemographic and clinical variables | Health and Use of Health Care in Italy; National Survey (2004–05) | Positive association. Healthcare workers in Italy with low (0.57OR, 0.39–0.81CI), medium (0.51OR, 0.37–0.71CI), or high (0.54OR, 0.39–0.71CI) education levels were less likely to be vaccinated compared to those with a post-graduate degree. |
 Cohen 2012 [14]; US | Education (Individual) | Low (less than HS, HS, or GED) or high (some college or college diploma) levels of education | Sociodemographic, health, clinical, and health belief variables | Participants of a RCT on flu transmission; Study in Washington Heights, New York (2006) | Positive association. Adults with higher levels of education were more likely to be vaccinated (1.20OR, 1,05–1,37CI) than those with lower levels. No significant relationship was found for children. |
 Henninger 2015 [15]; US | Education (Individual) | Education level (HS or GED or less, some college, bachelor’s degree, master’s degree or higher) | Sociodemographic variables, obstetric characteristics, survey items, and vaccination status | Pregnancy and Influenza Project; Large cohort of pregnant women seeking care from Kaiser Pemanente Northwest and Northern California (2010–11) | No association. Education level was not significantly associated with vaccination during pregnancy after adjusting for race and provider recommendation. |
 Jimenez-Trujillo 2015 [16]; Spain | Education (Individual) | Education level (primary, secondary, university) | Sociodemographic variables, health status and clinical variables | European Health Survey for Spain and Spanish National Health Survey; National Survey (2009; 2011) | No association. There was no significant association found between education level and influenza vaccine among persons aged 40–69 years with diabetes. |
 Lorenz 2013 [17]; US | Education (Individual) | Education level (less than HS, HS, more than HS) | Not reported | Patient survey and electronic medical records; Statewide survey and electronic medical records (2010–12) | Negative association. Mentally ill patients in Alabama with more than a high school education were less likely (0.29OR, 0.09–0.96CI) to be vaccinated compared to those with less than a high school education. |
 Simon 2016 [18]; US | Education (Individual) | Parents’ highest level of education (less than HS, HS graduate or GED, some college or associated degree, technical school degree, college degree or more) | Not reported | National Health Interview Survey; National survey (2005–13) | Positive association. Children with asthma whose parents had a college degree or higher (reference group) were more likely to receive influenza vaccination compared to those with parents who had some college, an associate’s degree, or some technical school (0.62 OR, 0.42–0.91 CI). |
Occupational class (n = 1; 1 positive association) | |||||
 Cleary 2014 [19]; Ireland | Class (Individual) | Socioeconomic group (occupational class): home duties, professional / manager / employer / non-manual, manual, unemployed, non-classifiable | Sociodemographic and pregnancy-related clinical variables; no adjustment was done in calculation for vaccination by SES group | Antenatal booking interview hospital data; Medical and clinical admission records (2009–10) | Positive association. Pregnant women from the professional / manager / employer group were more likely to be vaccinated against H1N1 than women in all other SES groups: home duties (0.61OR, 0.52–0.70CI), non-manual (0.81OR, 0.72–9.92CI), manual (0.54OR, 0.42–0.69CI), unemployed (0.77OR, 0.64–0.93CI), or non-classifiable (0.69OR, 0.55–0.87CI). |
Income or poverty (n = 5; 5 positive associations) | |||||
 Campitelli 2012 [20]; Canada | Income (Neighbourhood) | Linked postal code of residence to mean household income quintile in area (Q1 = lowest SES, Q5 = highest SES) | Sociodemographic and clinical variables | Hospital discharge, abstracts, physician claims, and other databases; Linked administrative data (2002–12) | Positive association. Infants from higher SES quintiles were more likely to be fully vaccinated against influenza during their first eligible winter, compared to children from lower SES areas (Q2 = 1.08OR, 1.04–1.11CI, Q3 = 1.12OR, 1.09–1.16CI, Q4 = 1.20OR, 1.23–1.32CI). The association remained significant for SES quintiles 3, 4, and 5 among low-birth weight infants. |
 Fox 2014 [21]; US | Income (Individual) | Federal poverty level for 2012: income above 200% the poverty level, income equal to or less than 200% poverty level | None | National Health Interview Survey; National survey (2011–12) | Positive association. Adults with a family income above 200% the federal poverty level were significantly more likely to receive an influenza vaccination compared to those below it (1.3PR, 1.3–1.3CI) |
 Lau 2013 [22]; US | Income (Household) | Household income percent of federal poverty level: 0–99%, 100–199%, 200–299, 300% or more | Sociodemographic variables, insurance status, and usual source of care | California Health Interview Survey; State survey (2005; 2007) | Positive association. After adjusting for gender, race/ethnicity, income, insurance status, and usual source of care, young adults aged 18 to 26 years with household incomes 200–299% above the federal poverty limit (1.57OR, 1.11–2.21CI) were more likely to be vaccinated compared to young adults of the same age with household incomes 0–99% FPL. |
 Narciso 2012 [23]; US | Income (Neighbourhood) | Neighbourhood poverty level (high [> 30% residents living below poverty], medium [20–29.9% residents living below poverty], low [less than 20% living below poverty level]) | Not reported | Vaccination data from school-located vaccination campaign; New York City schools (2009–10) | Positive association. The authors report lower levels of vaccination in boroughs with higher levels of poverty and provide the following vaccination prevalence rates: Manhattan (27.5%), Bronx (18.4%), Brooklyn (19.4%), Staten Island (16.9%), Queens (24.2%). |
 Villarroel 2016 [24]; US | Income (Household) | Income level (poor: below FPL, near-poor: 100% to less than 200% FPL, not poor: 200% or greater FPL) | Not reported | National Health Interview Survey; National survey (2015) | Positive association. Among adults diagnosed with diabetes, 50.9% who were poor had received an influenza vaccine, compared to those who were 57.8% near-poor and 65.9% not-poor. This linear trend was significant at p < 0.05. |