Changes in Tdap and MCV4 Vaccine Coverage Following Enactment of a Statewide Requirement of Tdap Vaccination for Entry Into Sixth Grade

摘要

Objectives. We evaluated changes in tetanus toxoid, reduced diptheria toxoid, acellular pertussis (Tdap), and tetravalen meningococcal (MCV4) vaccine coverage following enactment of a New York State mandate requiring Tdap before entering sixth grade. Methods. Using data from a hospital-based immunization registry, we measured Tdap and MCV4 coverage among youths aged 11 to 14 years in New York City at 3 time points: premandate, mandate year 1, and mandate year 2. Results. Among overlapping cohorts of 4316 (premandate), 4131 (mandate year 1), and 3639 (mandate year 2) youths, Tdap coverage increased steadily over time (29%, 58%, and 83%, respectively). Increases were observed among all ages. Across the same time points, MCV4 coverage also increased (10%, 30%, and 60%, respectively). Most adolescents did not receive MCV4 during the same visit they received Tdap. Conclusions. A Tdap school-entry mandate was associated with substantial increases in immunization coverage, even in age groups not directly affected by the mandate. At the postmandate time points, MCV4 coverage remained lower than Tdap coverage. Provider education should emphasize the importance of reviewing vaccine records and administering all recommended vaccines at every clinical encounter. In recent years, new vaccines against pertussis 1 and meningitis 2 have been introduced to the routine immunization schedule for children and adolescents. Both are recommended for youths aged 11 to 12 years, with catch-up vaccination for older adolescents. Pertussis is a highly contagious infection, often causing school or community outbreaks. Among healthy adolescents, pertussis is usually a self-limited illness characterized by a prolonged cough. However, secondary complications can occur, and adolescents serve as an important reservoir for transmission to infants, for whom infection can lead to pneumonia, respiratory failure, apnea, and even death. 3 The tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine has been shown to be 92% effective in preventing culture-confirmed pertussis. 4 Adolescents, and specifically those in crowded living conditions, have been shown to be at increased risk for N. meningitides infection. 5 N. meningitides is highly contagious and can cause meningitis, septicemia, and death. The tetravalent meningococcal polysaccharide-protein conjugate (MCV4) vaccine has been shown to be safe and highly immunogenic in protecting against N. meningitides infection. 6 Although the Tdap and MCV4 vaccines hold great promise, achieving high immunization coverage among adolescents remains a challenge. Barriers to adolescent immunization include failure to present for medical services, missed immunization opportunities, and scattered immunization records. 7 Few adolescents report the receipt of annual preventive health visits, 8 so reviewing immunization status and immunizing at every clinical encounter is key to increasing vaccine coverage in this population. Results of the 2008 National Immunization Survey–Teen indicate that among adolescents aged 13 to 17 years, nationwide coverage for Tdap and MCV4 remains low (41% and 42%, respectively). 9 Mandates requiring immunization prior to school entry have been highly effective in increasing immunization coverage. 10 – 14 In 1 study, hepatitis B immunization rates increased from 13% to 71% following implementation of a middle school mandate. 15 Mandates were initially used to promote the uptake of vaccines for highly contagious infectious diseases and thus to prevent school-based outbreaks, but today many states mandate vaccines for diseases that are not communicable (tetanus) or that are communicable primarily through sexual or blood exposures (hepatitis B). Recent controversy regarding mandates for the human papillomavirus vaccine has resulted in significant backlash against mandates, 16 – 18 highlighting the need for states to be judicious in their decisions to implement new mandates. Although mandates are known to rapidly increase vaccine coverage in their target population, there is little evidence of any carryover benefits. No studies to date have evaluated whether a new mandate will result in improved vaccine coverage for nonmandated age groups or for other nonmandated, age-appropriate vaccines. In the fall of 2007, New York State became one of the first states to require Tdap prior to entering sixth grade. This situation provided a unique opportunity to observe postmandate changes in coverage for Tdap (the mandated vaccine) and MCV4 (a nonmandated, recommended vaccine) across multiple age groups.