A recent report published by the Centers for Disease Control and Prevention (CDC) sheds light on the effectiveness of Covid-19 vaccines in children. Despite the lower severity of the disease in children compared to other age groups, it can still result in hospitalizations and deaths. In fact, Covid-19 was one of the leading causes of death among people under 20 in the United States between August 2021 and July 2022.
To address this, the Food and Drug Administration previously granted emergency use authorization to the Moderna and Pfizer-BioNTech vaccines for children over six months old. However, the approval was based primarily on safety trials and the ability of the vaccines to produce antibodies in children. The new study focuses on vaccine effectiveness in reducing severe disease.
The researchers assessed the vaccination status of children who visited emergency departments or urgent care centers with Covid-19-like symptoms and recorded their SARS-CoV-2 testing results. The study included over 90,000 children for the Moderna vaccine and approximately 81,000 children for the Pfizer-BioNTech vaccine.
Among unvaccinated children, around 5.5% in the Moderna group and 5.9% in the Pfizer-BioNTech group tested positive for the virus. Partially vaccinated children showed only slightly lower positivity rates. However, those who received the full recommended regimen had a significantly lower positivity rate, with less than 3% testing positive. For children who received three doses of the Pfizer-BioNTech vaccine less than two months before their visit, only 1.1% had a positive result.
The data also suggest that children who received a bivalent booster after the initial vaccines had greater protection, although the number of children in this category was low. Additionally, immunity in children, like in adults, is believed to decrease over time. Children who had been vaccinated more than two months before their visit had less protection. It is worth noting that children who received a combination of Moderna and Pfizer-BioNTech vaccines were excluded from the analysis.