Children aged 5-11 will receive a smaller dose of the Pfizer/BioNTech vaccine, using smaller needles. The dose for these children is 10 micrograms, one-third of that used in teens and adults. Children’s immune systems are more responsive than those of adults and in clinical trials, the smaller dose was found to produce a robust immune response. Children will receive two doses of the Pfizer-BioNTech vaccine spaced three weeks apart, the same timing as for older age groups. Vaccine trials for children younger than 5, using even smaller doses, are ongoing. Pfizer representatives have said they expect to report results for the youngest children before the end of this year. The Food and Drug Administration and the CDC will then consider the results, with possible authorization for young children in early 2022. For more information on the pediatric COVID-19 vaccine, read our Pediatric Vaccine FAQs.