— Coverage "substantially lags behind that in older children," researchers say. Credit: Jennifer Henderson, Enterprise & Investigative Writer, MedPage Today February 16, 2023
COVID-19 vaccination coverage in kids ages 6 months to 4 years was exceedingly low in the 6 months following FDA's authorization last June, CDC data showed.
Through the end of 2022, only 10.1% of children in this age group had received at least one dose of Moderna or Pfizer's mRNA vaccine, and just 5.1% had completed their two- or three-dose primary series reported Bhavini Patel Murthy, MD, of CDC's National Center for Immunization and Respiratory Diseases in Atlanta, and colleagues in Morbidity and Mortality Weekly Report (MMWR).
Coverage with at least one dose in this group "substantially lags behind that in older children," wrote Murthy and colleagues, who pointed to rates of 24.0% in children ages 5 to 11 years and 33.3% for adolescents ages 12 to 15 years in just the 2 months following FDA authorizations for those groups.
In a second MMWR, CDC researchers led by Katherine Fleming-Dutra, MD, also of the National Center for Immunization and Respiratory Diseases, detailed real-world protection of the mRNA vaccines in children ages 3 to 5 years, which showed vaccine effectiveness (VE) of 31-60% through 4 months following vaccination.
"Children should stay up to date with recommended COVID-19 vaccines, including completing the primary series; those who are eligible should receive a bivalent vaccine dose," wrote Fleming-Dutra and colleagues.
Vaccination Coverage in Youngest Kids
To study COVID vaccination coverage in kids ages 6 months to 4 years, Murthy and colleagues assessed vaccine administration data for the U.S., looking at the time of their authorization for this age group on June 17, 2022, through Dec. 31, 2022. Over this period, a total of 1,755,596 children in this age group had received at least one dose of a COVID vaccine.
By state or jurisdiction, coverage with at least one dose was lowest in Mississippi (2.1%), Louisiana (2.6%), and Alabama (3.1%), while highest in Massachusetts (21.6%), Vermont (31.7%), and the District of Columbia (36.1%). County-level data showed that coverage with one or more doses was lower in rural counties (3.4%) than in urban counties (10.5%).
"The low coverage to date in children aged 6 months to 4 years is concerning and might indicate challenges to future vaccination coverage, especially given that bivalent booster doses are now authorized for this pediatric population as well," Murthy and colleagues wrote.
The researchers also reported disparities in coverage by race and ethnicity among this age group, with higher percentages of white and Asian children vaccinated with at least one dose versus their share of the population, and lower percentages of Black and Hispanic children vaccinated compared with their share of the population:
White: 55.3% vaccinated vs 48.4% of the population
Asian: 13.4% vs 5.7%, respectively
Black: 7% vs 13.9%
Hispanic: 19.9% vs 25.9%
Limitations to the research included that records may not have been linked if children received first and additional doses at different vaccination sites -- for example a pharmacy versus a mass vaccination site, which may have different methods for submitting data. Additional limitations included that race and ethnicity data were not available for 30% of the children.
Real-World Effectiveness in Kids 3 to 5 Years
To assess the real-world protection provided by the mRNA vaccines in younger kids, Fleming-Dutra and colleagues turned to data from the Increasing Community Access to Testing (ICATT) program, which provides COVID testing to individuals ages 3 or older at pharmacy and community-based testing sites nationwide. Data spanned from early July 2022 to early February 2023 and looked at kids ages 3 to 5 years for Moderna's vaccine and 3 to 4 years for Pfizer's. For Moderna's vaccine, VE of two monovalent doses (a complete primary series) against symptomatic infection was 60% (95% CI 49-68) in the 2 weeks to 2 months after the second dose and 36% (95% CI 15-52) in the 3 to 4 months after the second dose.
The findings were similar to the clinical trial data that led to the authorization of Moderna's vaccine in this younger group, which showed vaccine efficacy of 50.6% (95% CI 21.4-68.6) for those ages 6 to 23 months and 36.8% (95% CI 12.5-54.0) for those ages 2 to 5 years.
In the case of Pfizer's vaccine, Fleming-Dutra's group reported a VE of 31% (95% CI 7-49) against symptomatic infection with three monovalent doses (a complete primary series) at 2 weeks to 4 months after the third dose. Statistical power was not sufficient to estimate VE stratified by time since receipt of the third dose.
By comparison, clinical trial data for Pfizer's vaccine in kids aged 6 months to 4 years showed vaccine efficacy of 73.2% (95% CI 43.8-87.6) against symptomatic COVID following receipt of a third dose, though the findings were based on a small number of cases.
ORIGINAL ARTICLE: https://www.medpagetoday.com/infectiousdisease/covid19vaccine/103145
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