Vaccine effectiveness waned significantly after ≥150 days during the omicron variant phase
By Lori Solomon HealthDay Reporter
WEDNESDAY, April 19, 2023 (HealthDay News) — BNT162b2 protects children and adolescents against mild-to-moderate and severe COVID-19, according to a study published online April 7 in Pediatrics.
Nicola P. Klein, M.D., Ph.D., from Kaiser Permanente Northern California in Oakland, and colleagues assessed BNT162b2 vaccine effectiveness against mild-to-moderate and severe COVID-19 in children and adolescents through the omicron BA.4/BA.5 period. The analysis included 9,800 emergency department/urgent care cases with 70,232 controls and 305 hospitalized cases with 2,612 controls.
The researchers found that during the delta variant phase, two-dose vaccine effectiveness against emergency/urgent encounters at 12 to 15 years was initially 93 percent, but waned to 77 percent after ≥150 days. For individuals aged 16 to 17 years, vaccine effectiveness was initially 93 percent but waned to 72 percent after ≥150 days. During the omicron variant phase, vaccine effectiveness for those aged 12 to 15 years was initially 64 percent, waning to 13 percent after ≥150 days, and was 31 percent for those aged 16 to 17 years, waning to 7 percent. A monovalent booster increased vaccine effectiveness to 54 and 46 percent for the two age groups, respectively. For children aged 5 to 11 years, two-dose vaccine effectiveness was initially 49 percent, with waning to 41 percent after 150 days.
“Children and adolescents should receive all recommended COVID-19 vaccinations,” the authors write.
Two authors disclosed financial ties to the pharmaceutical industry.
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