Perspective

Kindergarteners maintain high vaccination rates despite increasing exemptions

Although kindergarteners enrolled in the 2017-2018 school year were able to maintain high rates of vaccination coverage — specifically with the measles, mumps and rubella; DTaP; and varicella vaccines — researchers observed a slight increase in vaccine exemptions.

In an MMWR, Jenelle L. Mellerson, MPH, an epidemiologist at Certified Technical Experts Inc. and the CDC’s National Center for Immunization and Respiratory Disease, and colleagues examined nationwide coverage rates with state-required vaccinations of DTaP, MMR and varicella using data reported to the CDC for the 2017-2018 school year. Data concerning state-required immunization for kindergarteners attending public school was were provided by 49 states and the District of Columbia, and 48 states and D.C. provided this information for students attending private school.

According to the researchers, 28 of the states included in the study allowed approximately 2,825,691 students to attend school under a grace period or provisional enrollment, which allows the student to enroll and attend classes without proof of complete vaccination or exemption.

The remaining students had either vaccinations (n = 3,988,127) or exemptions (3,634,631).

When Mellerson and colleagues examined MMR coverage, kindergarteners had a median reported coverage of 94.3% — ranging from 81.3% in D.C. to at least 99.4% in Mississippi. Coverage was at least 95% for 23 states, and three states and D.C. reported coverage of less than 90%.

More students received DTaP, researchers said, with a median coverage of 95.1% (range = 79.7% [D.C.] to 99.4% [Mississippi]), and more states reporting coverage of at least 95% (n = 25). Three states and D.C. reported coverage of DTaP vaccination at less than 90%.

The researchers noted that 41 states and D.C. require immunization with two doses varicella vaccine, and the median coverage was 93.8% (range = 80.5% [D.C.] to 99.4% [Mississippi]). Seventeen states reported coverage of at least 95%, and four states and D.C. reported varicella vaccine coverage of less than 90%.

Exemptions from one or more vaccines increased between the 2016-2017 and 2017-2018 school years from a median percentage of 2% to 2.2% (range = 0.1% [Mississippi] to 7.6% [Oregon]). Medical reasons accounted for 0.2% of exemptions, with Hawaii reporting the lowest number of these exemptions (less than 0.1%) and Alaska reporting the most (0.8%). The remaining exemptions, according to the researchers, were nonmedical (range = less than 0.1% [California] to 7.5% [Oregon]).

The researchers wrote that among the 29 states and D.C. where exemption rates increased, 15 states reached a median coverage of at least 95% for MMR, 16 reached a median coverage of at least 95% for DTaP and 11 states reached a median coverage at least 95% for varicella.

Mellerson and colleagues said that targeting children who attend schools through a grace period or provisional enrollment would help to improve vaccination coverage

“In 11 of the 28 states reporting 2017-2018 grace period or provisional enrollment data, the percentage of kindergarteners in these groups at the time of assessment exceeded the percentage with an exemption from one or more vaccines, representing a group of children who could be fully vaccinated with appropriate follow-up,” the researchers wrote. “CDC encourages these programs to collect and use these data to identify populations of undervaccinated students. Almost all states could achieve at least 95% vaccination coverage if undervaccinated nonexempt children were vaccinated in accordance with local and state vaccination policies.”

Coverage among children aged 19 to 35 months

A separate report in MMWR also highlighted high rates of vaccination coverage that remained stable among children aged 19 to 35 months in the United States in 2017. Coverage was greater than 90% for vaccination with at least three doses of poliovirus vaccine (92.7%), at least one dose of MMR (91.5%), at least three doses of hepatitis B virus vaccine (91.4%), and at least one dose of varicella vaccine (91%).

However, researchers observed a gradual increase in the number of children who received no vaccines by age 2 years — increasing from 0.9% for children born in 2011 to 1.3% for those born in 2015.

The researchers suggested that rates could be improved through collaboration with state immunization programs, reducing interruptions in insurance coverage, greater awareness of the federally-funded Vaccines for Children program, and by eliminating missed opportunities to vaccinate children during visits to health providers, especially among those in rural areas. – by Katherine Bortz

References:

Hill HA, et al. MMWR Morb Mortal Wkly Rep. 2018;doi;10.15585/mmwr.mm6740a4.

Mellerson JL, et al. MMWR Morb Mortal Wkly Rep. 2018;doi:10.15585/mmwr.mm6740a3.

Disclosures: The authors report no relevant financial disclosures.

Although kindergarteners enrolled in the 2017-2018 school year were able to maintain high rates of vaccination coverage — specifically with the measles, mumps and rubella; DTaP; and varicella vaccines — researchers observed a slight increase in vaccine exemptions.

In an MMWR, Jenelle L. Mellerson, MPH, an epidemiologist at Certified Technical Experts Inc. and the CDC’s National Center for Immunization and Respiratory Disease, and colleagues examined nationwide coverage rates with state-required vaccinations of DTaP, MMR and varicella using data reported to the CDC for the 2017-2018 school year. Data concerning state-required immunization for kindergarteners attending public school was were provided by 49 states and the District of Columbia, and 48 states and D.C. provided this information for students attending private school.

According to the researchers, 28 of the states included in the study allowed approximately 2,825,691 students to attend school under a grace period or provisional enrollment, which allows the student to enroll and attend classes without proof of complete vaccination or exemption.

The remaining students had either vaccinations (n = 3,988,127) or exemptions (3,634,631).

When Mellerson and colleagues examined MMR coverage, kindergarteners had a median reported coverage of 94.3% — ranging from 81.3% in D.C. to at least 99.4% in Mississippi. Coverage was at least 95% for 23 states, and three states and D.C. reported coverage of less than 90%.

More students received DTaP, researchers said, with a median coverage of 95.1% (range = 79.7% [D.C.] to 99.4% [Mississippi]), and more states reporting coverage of at least 95% (n = 25). Three states and D.C. reported coverage of DTaP vaccination at less than 90%.

The researchers noted that 41 states and D.C. require immunization with two doses varicella vaccine, and the median coverage was 93.8% (range = 80.5% [D.C.] to 99.4% [Mississippi]). Seventeen states reported coverage of at least 95%, and four states and D.C. reported varicella vaccine coverage of less than 90%.

Exemptions from one or more vaccines increased between the 2016-2017 and 2017-2018 school years from a median percentage of 2% to 2.2% (range = 0.1% [Mississippi] to 7.6% [Oregon]). Medical reasons accounted for 0.2% of exemptions, with Hawaii reporting the lowest number of these exemptions (less than 0.1%) and Alaska reporting the most (0.8%). The remaining exemptions, according to the researchers, were nonmedical (range = less than 0.1% [California] to 7.5% [Oregon]).

The researchers wrote that among the 29 states and D.C. where exemption rates increased, 15 states reached a median coverage of at least 95% for MMR, 16 reached a median coverage of at least 95% for DTaP and 11 states reached a median coverage at least 95% for varicella.

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Mellerson and colleagues said that targeting children who attend schools through a grace period or provisional enrollment would help to improve vaccination coverage

“In 11 of the 28 states reporting 2017-2018 grace period or provisional enrollment data, the percentage of kindergarteners in these groups at the time of assessment exceeded the percentage with an exemption from one or more vaccines, representing a group of children who could be fully vaccinated with appropriate follow-up,” the researchers wrote. “CDC encourages these programs to collect and use these data to identify populations of undervaccinated students. Almost all states could achieve at least 95% vaccination coverage if undervaccinated nonexempt children were vaccinated in accordance with local and state vaccination policies.”

Coverage among children aged 19 to 35 months

A separate report in MMWR also highlighted high rates of vaccination coverage that remained stable among children aged 19 to 35 months in the United States in 2017. Coverage was greater than 90% for vaccination with at least three doses of poliovirus vaccine (92.7%), at least one dose of MMR (91.5%), at least three doses of hepatitis B virus vaccine (91.4%), and at least one dose of varicella vaccine (91%).

However, researchers observed a gradual increase in the number of children who received no vaccines by age 2 years — increasing from 0.9% for children born in 2011 to 1.3% for those born in 2015.

The researchers suggested that rates could be improved through collaboration with state immunization programs, reducing interruptions in insurance coverage, greater awareness of the federally-funded Vaccines for Children program, and by eliminating missed opportunities to vaccinate children during visits to health providers, especially among those in rural areas. – by Katherine Bortz

References:

Hill HA, et al. MMWR Morb Mortal Wkly Rep. 2018;doi;10.15585/mmwr.mm6740a4.

Mellerson JL, et al. MMWR Morb Mortal Wkly Rep. 2018;doi:10.15585/mmwr.mm6740a3.

Disclosures: The authors report no relevant financial disclosures.

    Perspective
    Matthew Zahn

    Matthew Zahn

    Increases in the number of children not receiving vaccines are always a concern, and there are always new pieces of information and misinformation regarding the safety and efficacy of vaccines. The overall immunization rates remain high, but the increase in number of kids who have had no immunizations is concerning. We will have to watch this rate over time.

    I would find it hard to say that there is one individual reason for this increase. There are multiple drivers of immunization, and unfortunately, there is a fair amount of information driving vaccine hesitance. It is up to providers to make sure they continue to provide the correct information and to encourage families to vaccinate their children.

    One of the issues identified in this report that I think is a public health concern is that lack of immunization was related to the lack of insurance and to patients residing in rural communities. This information indicates a potential issue associated with access to health care. We often think about lower vaccine rates simply as vaccine hesitancy, which may be the case for the children who got no vaccines, but an overall lower immunization rate in children who do not have access to insurance reminds us how important the Vaccines for Children program is. It is also a reminder that we make sure the program reaches every child so they have the opportunity to get vaccinated.

    • Matthew Zahn, MD
    • Chair of the IDSA Public Health Committee
      Medical director of the Orange County Public Health epidemiology program

    Disclosures: Zahn reports no relevant financial disclosures.