Determinants of pertussis and tetanus vaccination coverage among foreign-born adults living in the United States

Abstract

Pertussis is a common vaccine-preventable disease worldwide and is endemic in the United States, with an average of 23,000 cases reported annually. The incidence of pertussis among adults has increased steadily, with a fifth of the cases reported in 2013 in persons >20 years old. Up to 55% of cases in infants can be attributed to adult family members. Despite this recognized risk and current Advisory Committee on Immunization Practices (ACIP) recommendations for universal adult tetanus, diphtheria, and acellular pertussis (Tdap) vaccination, reported vaccination coverage among adults remains suboptimal. The estimated 41.3 million foreign-born individuals living in the United States in 2013 had significantly lower reported coverage for Td and Tdap among adults compared to the U.S-born. We used data from the 2012 and 2013 National Health Interview Survey (NHIS) to calculate point estimates and 95% confidence intervals of vaccination coverage among foreign born adults. Multivariable logistic regression was conducted to assess Td and Tdap vaccination in relation to migration-related, socio-demographic, and access-to-care variables using prevalence ratios (PR). Five factors were significantly associated with vaccination status after controlling for all other variables. Age greater than 49 years and having public or no health insurance were associated with lower vaccination rates for both vaccines. Having an associate degree or higher education was significantly associated with higher Tdap and Td vaccination coverage. Having at one visit with a doctor in the previous year was significantly associated with having received each vaccine and there was a general trend towards increased coverage with increasing number of visits encounters; 69.9% of respondents reported at least one encounter. Tdap coverage was 13.4 % with 10 or more encounters. Migration-related factors were not associated with lower vaccination rates in this study, our results suggest that the low coverage reported for both foreign born and native born people individuals are most likely due to vaccine system delivery factors that can be modified. Vaccination remains suboptimal even in the face of repeated healthcare encounters. This finding, along with the finding that public insurance is associated with lower vaccination coverage for Tdap and Td, suggests that there may be substantial missed opportunities for vaccination for public insurance holders. Opportunities to provide vaccine during health care visits should be taken. Actions might include outreach and education to immigrants and designing vaccine delivery systems to reduce missed opportunities.