The impact of changing medicaid enrollments on New Mexico's Immunization Program

Abstract

Background: Immunizations are an important component to pediatric primary care. New Mexico is a relatively poor and rural state which has sometimes struggled to achieve and maintain its childhood immunization rates. We evaluated New Mexico's immunization rates between 1996 and 2006. Specifically, we examined the increase in immunization rates between 2002 and 2004, and how this increase may have been associated with Medicaid enrollment levels, as opposed to changes in government policies concerning immunization practices.

Methods and findings: This study examines trends in childhood immunization coverage rates relative to Medicaid enrollment among those receiving Temporary Assistance for Needy Families (TANF) in New Mexico. Information on health policy changes and immunization coverage was obtained from state governmental sources and the National Immunization Survey. We found statistically significant correlations varying from 0.86 to 0.93 between immunization rates and Medicaid enrollment.

Conclusions: New Mexico's improvement and subsequent deterioration in immunization rates corresponded with changing Medicaid coverage, rather than the state's efforts to change immunization practices. Maintaining high Medicaid enrollment levels may be important for achieving high childhood immunization levels.

Figure 1. Total Medicaid enrollment levels between 1997 and 2006.

Figure 2. Temporal trends in immunization coverage levels and TANF Medicaid enrollment in New Mexico between June 1998 and June 2005.

The NIS immunization coverage estimates are lagged by 12 months. It is important to note that NIS estimates for June 2005 reflecting immunizations in 2004 are not available.