Vaccination is a medical intervention with direct benefits to both individuals and communities. When a large percentage of a population is vaccinated, the entire community (vaccinated and unvaccinated) receives additional protection from vaccine preventable diseases. This concept, known as 'herd immunity,' is the primary justification for mandatory vaccination policies in the United States. By following the recommended schedule and fully immunizing children on time, parents protect their children against 14 vaccine preventable diseases. If a high enough percentage of children are vaccinated, outbreaks can also be prevented.

In the U.S., all states require children attending public school or state-licensed childcare facilities to receive a series of vaccinations. Vaccination requirements for school and childcare attendance are critical to ensuring high rates of vaccination. Linking vaccination with school attendance, which is also required by law, ensures that vaccines reach the greatest number of children. Schools are a prime venue for the transmission of vaccine-preventable disease, and active school-age children can further spread disease to their families and others with whom they interact.*

Specific vaccine requirements for school and childcare vary by state. The Connecticut immunization laws and regulations can be found on the Department of Public Health’s web page. In CT, school and childcare programs are responsible for ensuring that attendees meet the vaccine requirements. Children who do not meet vaccine requirements can attend school if they have received all vaccines for which they are eligible and are on a catch-up schedule or have a physician’s note verifying an appointment to receive vaccines is scheduled.

Each year the Connecticut Department of Public Health Immunization Program conducts education-based immunization surveys, including the pre-kindergarten** (pre-K) through 12th grade school survey. These immunization surveys are used to determine the extent to which children, adolescents, and young adults in education in Connecticut are protected from vaccine-preventable diseases. They collect school-level data on the number of attendees who have received required vaccines and the number who have submitted documentation to claim an exemption. Individual vaccine information on each student is not collected.

Data presented here are on completion of school-entry mandated vaccine series for children enrolled in kindergarten and 7th grade, on mandated influenza vaccination for children enrolled in pre-K, and on vaccination exemptions (medical and religious) for all children enrolled in grades pre-K through 12. School-mandated vaccine series for students enrolled in kindergarten are inactivated polio, DTaP (diphtheria, tetanus, and acellular pertussis), MMR (measles, mumps, and rubella), hepatitis B, varicella and hepatitis A. Additional mandated vaccines for students enrolled in 7th grade include meningococcal conjugate vaccine (MCV) and Tdap (tetanus, diphtheria, and acellular pertussis). Influenza vaccine is a requirement for pre-K students who are 24 through 59 months of age. For each required vaccine children are categorized as either compliant or not compliant. These categories are not intended to be legal terms, but a simplified measure for survey purposes. Students are counted as compliant if they have submitted proof of immunity, such as vaccination records, or have submitted a valid exemption. Students are counted as not compliant if they have not submitted documented proof of immunity, are on a catch-up schedule, or have a doctor’s note verifying a scheduled appointment to receive vaccines.

Typically survey results for the current school year are available by the fall of the following year.

The percentage of Connecticut kindergarten students receiving required MMR vaccines in the 2022–2023 school year is 97.3%. This is an increase of 1.6% from the previous year and the highest single year increase since 2012–2013 (see Figure 1). For public schools, the MMR rate is 97.9% and for private schools it is 93.9%. To achieve herd immunity for measles, 95% of the population must be vaccinated or have had the disease.*** Among schools with more than 30 kindergarten students, compared with last year there was a 16.4% increase in the number of schools with MMR vaccination rates at or above 95%; only 70 schools reported MMR rates below 95%, compared to 119 schools the previous year.

Public Act (PA) 21-6 amended current statutes relating to vaccine exemptions in Connecticut, repealing religious exemptions for Connecticut students. Children who were enrolled in kindergarten and who had a valid religious exemption on file before the time of passage of PA 21-6 on April 28, 2021, were allowed to keep their exemptions for their remaining school years (through grade 12).

During the 2022-2023 school year, the impacts of PA 21-6 were significant for Pre-K and kindergarten students, since these are the grades that could not have been enrolled in kindergarten prior to April 28, 2021.

Some states, such as California, that discontinued religious or philosophical exemptions saw an increase in the percentage of medical exemptions claimed by students during subsequent years. In Connecticut the percentage of kindergarten students with a medical exemption remained steady at 0.3%, which is within the range of fluctuation of 0.1% seen during the past decade (see Figure 2).

In addition to immunization rates increasing for each vaccine, the percentage of kindergarten students with a religious exemption decreased from 2.1% to 0.5% (see Figure 2) and the percentage of Pre-K students with a religious exemption saw a continued decreased from 1.9% to 0.2% (see Figure 3). The national average during 2022–23 for non-medical exemptions was 2.8%****.

Click here to see State-level annual pre-K through 12th grade survey results for kindergarten, seventh grade, and influenza vaccine for pre-K.

Click here to see County-level annual pre-K through 12th grade survey results for kindergarten, seventh grade, and influenza vaccine for pre-K.

Includes annual pre-K through 12th grade survey results for each reporting school. You can look up individual schools to see immunization rates, exemption rates, and other related information.  Results for schools with less than 30 students are not shown in the tables. 

*http://www.cdc.gov/vaccines/imz-managers/guides-pubs/downloads/vacc_mandates_chptr13.pdf

**Includes pre-kindergarten programs run by local boards of education; programs located in childcare centers are counted on the childcare survey.

***https://www.cdc.gov/grand-rounds/pp/2020/20200218-measles-elimination-vaccine.html

****MMWR: Coverage with Selected Vaccines and Exemption from School Vaccine Requirements Among Children in Kindergarten — United States, 2022–23 School Year