key: cord-0282892-6f48fgre
authors: Spicer, Kevin B.; Glick, Connor; Cavanaugh, Alyson M.; Thoroughman, Douglas
title: Association of SARS-CoV-2 Vaccination or a Prior Positive Test Result in Adolescents during the Delta Variant Surge in Kentucky
date: 2022-05-27
journal: nan
DOI: 10.1016/j.jpeds.2022.05.034
sha: d2f85dcc029f6c7f05f5198425352850a90ea542
doc_id: 282892
cord_uid: 6f48fgre

In a cross-sectional study of 89,736 adolescents in Kentucky, SARS-CoV-2 vaccination provided estimated protection of 81% against infection when the highly transmissible Delta variant was predominant. Vaccination provided added benefit to those with history of prior infection. These findings support the recommendation that all adolescents receive vaccination.

Data for vaccines administered in Kentucky are maintained in the KY immunization registry (KYIR). Vaccination status was determined from review of KYIR for those adolescents who had test results in EDSS for August and September 2021. Only adolescents vaccinated with an mRNA vaccine (Pfizer-BioNTech or Moderna) were included in the vaccinated group. Adolescents who received the Janssen vaccine or a vaccine with unspecified manufacturer prior to the testing date were excluded.

Definitions: "vaccination" -completion of primary vaccination series ≥14 days prior to date of testing during the study period (August 1 -September 30, 2021); "no vaccination" -no vaccine received prior to date of testing; "prior positive test result" -positive test >90 days prior to a test result during the study period. Those who received only one dose of vaccine or completed the primary vaccine series within 14 days of testing were excluded from analysis. The first test was used for adolescents with multiple tests during the study period with concordant results.

Adolescents with both negative and positive test results within the study period were included based upon the positive test result.

Prevalence ratios (PRs) and 95% confidence intervals (CIs) were calculated comparing vaccination and no prior positive test result, no vaccination but prior positive test result, and vaccination plus prior positive test result with: no vaccination and no prior positive test result.

PRs and 95% CIs were calculated for those with prior positive test results comparing those who were not vaccinated with those who were vaccinated. PRs were also calculated adjusted for age and sex. Inclusion of age and sex in PR calculations changed estimates by <5%; consequently, against reinfection during the study period. Additional data regarding protection from reinfection after initial SARS-CoV-2 infection in adolescents are lacking, but estimated protection in the current study is lower than that obtained for adults aged 20-39 years in a study from Kentucky for cases in 2020. Estimated protection against reinfection in that study was 81%, but the study was performed in the pre-Delta era and utilized a different study design. 8 In an adult population, the positive benefit of vaccination in those with history of a positive test result was reported from Kentucky (pre-Delta), where reinfected adults had more than two times the odds of being unvaccinated compared to controls without reinfection. 9 The findings in this report are subject to limitations. inconsistencies between data sources may 

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The authors appreciate the assistance of the Data, Breakthrough, and Reinfection teams within the Division of Epidemiology and Health Planning at the Kentucky Department for Public Health.