According to a study, the effectiveness of the Pfizer COVID-19 vaccine for children diminished swiftly during the Omicron outbreak in the United States, particularly among children aged 5 to 11, but the vaccine was still protective against severe disease.
The effectiveness of the Pfizer vaccine against COVID cases and hospitalizations was estimated by researchers from the New York State Department of Health and the University of Albany School of Public Health in the United States.
During December 2021 and January 2022, they used data from 852,384 fully vaccinated children aged 12-17 years and 365,502 children aged 5-11 years.
Within one month of being fully vaccinated, the effectiveness of the Pfizer shots against infection caused by the Omicron variant fell from 68 percent to just 12 percent in children 5 to 11 years old, according to the yet-to-be peer-reviewed study, which was posted on the preprint repository MedRxiv on Monday.
In the same age group, effectiveness against hospitalisation was higher, but it also declined significantly, from 100% in early December to just 48% by the end of January.
The study also discovered that while vaccine effectiveness declined in older children and teenagers, it did so at a slower rate than in younger children.
The vaccine’s effectiveness for children aged 12 to 17 years old dropped from 66% in early December to 51% by the end of January, according to the study.
