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The problem
Intervention: COVID-19 messenger RNA vaccination
Who it was tested with: Children aged 6 months to 11 years in Niigata, Japan, presenting with upper respiratory tract symptoms during April 2023 to April 2024.
Experience from people who deliver programmes: stories, case studies and lessons learned. Valuable for understanding how and why, and for spotting what to test next, but not a measure of effect.
"A prospective, test-negative, case-control study was conducted between April 2023 and April 2024 at 9 pediatric clinics in Niigata, Japan. Patients aged 6 months to 11 years with upper respiratory tract symptoms were tested for SARS-CoV-2, and a multivariable logistic regression model was used to calculate VE against symptomatic COVID-19." This design provides stronger evidence than observational studies alone by comparing outcomes between exposed and unexposed groups, though it lacks randomization.
Test-negative case-control design is observational rather than randomized; findings apply to omicron subvariants in one prefecture of Japan; cannot determine whether protection loss over time reflects true waning or emergence of escape variants; relatively small numbers at 6+ months timepoint
Across countries and designs
6 studies · 4 countries
