Background
This annual report shows immunization coverage from 2020-2023 among Vermont children, based on data in the Vermont Immunization Registry (IMR). It highlights changes from year to year and helps the Immunization Program focus their efforts to improve the health of Vermonters.
Ages used in this report are calculated as of December 31, 2023 and rates are based on immunizations given through that date.
About the IMR
The IMR is a secure, centralized health information system that contains immunization histories for Vermonters. While reporting all immunizations given in Vermont is required by state law, the valuable resource of individual records is used across the state by health professionals. For example, its easy and secure access allows providers to determine if you need a tetanus shot when you show up in the emergency room with a cut finger. The data in the system also informs public health officials on the immunization rates of Vermonters by demographics, locations and immunization type.
2023 IMR Basic Statistics
As of December 31, 2023:
- Total Number of Patients with Immunization Records: 1,052,446 (increase of >175,446 since 2020)
- Total Number of Immunizations in the IMR: 14,295,140
- Number of Immunizations added in 2023: 903,701
- Hospitals reporting to the IMR: All VT hospitals and Dartmouth Hitchcock Medical Center in NH
- Percent of Chain Pharmacies reporting: 100%
- Number of Provider Sites (all types) reporting: 430
- Percent of Public Schools using the IMR: 99%
Immunization Coverage by the Age of Two
Traditionally, immunization coverage is assessed in young children after the age of 18 months, by which time Centers for Disease Control and Prevention (CDC) recommends children should have received:
- Four doses of DTaP (Diphtheria, Tetanus, Pertussis)
- Three doses of Polio
- One dose of MMR (Measles, Mumps, Rubella)
- Four doses of Hib (Haemophilus Influenza Type B)
- Three doses of HepB (Hepatitis B)
- One dose of Varicella
- Four doses of PCV (Pneumococcal)
Collectively, these are termed the Childhood Seven Series. In 2023, 75.8% of Vermont two-year olds were up to date for the Childhood Seven Series.
The table below shows rates by immunization series. Overall, immunization rates have remained stable since 2020. Of note, the DTaP series and the PCV series, both of which require four doses, continue to have the lowest rates.
Immunization rates (%) for 2 year olds are stable since 2020
Childhood Seven Series (age 2)
The below graph shows variability in the county level coverage for 2023. These ranged from a low of 45.5% in Essex County to a high of 82.5% in Addison County.
The table compares county coverage rates over time, from 2020 to 2023. Essex County consistently has the lowest Seven Series completion rate among all Vermont counties. Variability in coverage rate over the years is higher in smaller counties (e.g., Essex and Grand Isle) compared to larger counties (e.g., Chittenden) as changes are likely influenced by small population sizes.
By County 2023
By County 2020-2023: % complete (total immunized)
Coverage Among Vermont Teens by Age 15
Measuring immunization coverage in teens focuses on specific immunizations recommended from age 11 years forward, including:
- Human Papilloma Virus (HPV)
- Meningococcal vaccine
- Tdap (Tetanus, Diptheria, Pertussis)
Coverage rates of these three immunizations among teens (15 years old) were stable from 2020 to 2023 (see below figure), though rates are consistently lower for Meningococcal and HPV vaccine compared to Tdap.
Immunization rates (%) among 15 year olds are stable since 2020
Tdap, Meningococcal, HPV Vaccine by age 15, by County, 2023
HPV
HPV immunization is routinely recommended for teens at age 11-12. Teens who receive the first dose by the age of 15 need only one more dose to complete the series. Those who start after age 15 need a third dose to be protected. Two-thirds (65.7%) of Vermonters received at least one dose of HPV by age 15, with a low of 57.8% in Bennington County and a high of 74.3% in Grand Isle County (below map, HPV 1+ dose).
Statewide, 52.9% of Vermont youth aged 15 completed the HPV immunization series, well below the coverage goal of 80%. In only three Vermont counties, more than 55% of 15-year-olds have completed the series (below map, HPV 2+ doses). These include Addison, Grand Isle, Orange Counties. Teens who are immunized with HPV vaccine are protected against cervical, oral, genital and rectal cancers caused by this virus. In other areas of the state, immunization coverage is lower: Bennington, Essex, Windham and Windsor are all below 50%.
Meningococcal
Teens are recommended to receive two doses of Meningococcal vaccine. The first dose between age 11-12 years and the second dose at age 16. Meningococcal coverage is assessed by measuring how many teens have received at least one dose of Meningococcal vaccine by age 15. Meningococcal coverage by age 15 in Vermont in 2023 was 72.7%. The below map (Mening 1+ dose) shows coverage varies by county, with Caledonia, Franklin, Grand Isle, Orange, Orleans and Rutland Counties achieving over 75% coverage. Bennington, Windham and Windsor counties have coverage under 70%.
Tdap
Tdap coverage by age 15 is over 76.9%, but Essex and Windsor counties are more than five percentage points below the state rate (below map, Tdap 1+ dose).
Note: Tdap, Meningococcal, and HPV immunizations are all recommended for teens in this age group by the Advisory Committee for Immunization Practices (ACIP).
Hover mouse over counties to see %
HPV 1+ dose
HPV 2+ doses
Mening 1+ dose
Tdap 1+ dose
Summary table, by county
Hepatitis A Immunization Coverage, Various Age Groups
The immunization for Hepatitis A is a two-dose series beginning at 12 months old, with a second dose at least six months after the first. If the immunization is missed in their early years, children should complete the two-dose series before they turn 18.
The below figure shows rates for Hepatitis A immunization. Rates have increased over time among all age groups, with the largest improvement in the 2-4 year olds, from 69.1% in 2020 to 77.3% in 2023.
Hepatitis A immunization uptake is improving among all age groups, 2020-2023
Conclusion
Overall, immunization rates among children and teenagers in Vermont have remained stable from 2020 through end of 2023. There continues to be significant differences in immunization rates between some counties in the state. The Vermont Immunization Registry and Immunization Program will continue working together to understand and address these disparities.
Limitations
We are reporting these data using an IMR based denominator. We believe this is the most accurate way to report, since our numbers are based on actual individuals and not annual census estimates. We acknowledge this can make our denominators too large (and our rates, subsequently somewhat lower), as it is difficult to identify and exclude individuals who did live in Vermont but have now moved out of state. To control for this in the teen reporting only, we used the Ogive hybrid method recommended in the American Immunization Registry Association Analytic Guide for Assessing Vaccination Coverage and excluded individuals who have not received any immunizations in 10+ years.
Registry Data Sources
As of December 31, 2023, there were 1,052,446 individuals, and 14,295,140 immunizations in the Vermont Immunization Registry.
Approximately 88.3% of the 903,701 immunizations added to the IMR in 2023 came directly from electronic health records in provider offices and hospitals. Another 5.1% were loaded as flat files – many of these came from health insurers and others were historical information that medical practices and health clinics were able to provide. It is also possible for immunizers to directly enter information into the IMR, and this accounted for 6.6% of 2023 data.
Thank you to Vermont health care providers, hospitals, pharmacies and health insurers for their invaluable contributions to this health information system.