Understandably, many parents of young children have questions about the new coronavirus vaccines for babies and toddlers and the expected rollout next week of the Pfizer-BioNTech and Moderna shots. We talked with infectious disease pediatricians to get answers to the most common ones.
One specific question came from parents with 4-year-olds, particularly those who are just about to turn 5. Since a two-dose Pfizer vaccine has been available for children between 5 and 11 since last fall, they want to know if it makes sense to wait until their children turn 5 so they can get the more potent version of Pfizer. The Pfizer shots for children younger than 5 would be administered in three doses, which contain three micrograms while those for older children contain 10.
All the experts said not to wait, recommending that parents of 4-year-olds start the vaccination process as soon as possible, even if that would mean beginning with the lower dose version.
“The sooner you start them off getting protection, the better,” said Dr. Yvonne Maldonado, a pediatric infectious disease physician at Stanford Medicine who chairs the American Academy of Pediatrics’ committee on infectious diseases.
If your child turns 5 before a second or third dose of the Pfizer vaccine, they would likely get bumped up to receive the higher dose for the rest of the series, said Dr. Debbie-Ann Shirley, a pediatric infectious disease physician at the University of Virginia, as this is what the A.A.P. recommends for older children who transition into a new age group while receiving Covid-19 vaccines.
So, what about parents of 4-year-olds who are bigger than the average 5- or even 6-year-olds? As Christina Caron reported when the vaccine for school-age children was cleared, it does not matter whether a child is smaller or larger than other children their age when it comes to vaccines.
Weight is an important factor when you give a young child medication like Tylenol because there is a wide variation in weight from infancy throughout childhood and too much of the drug could be toxic.
The optimal vaccine dose, however, is dependent on age and tailored to minimize potential side effects.
Parents with 4-year-olds do have another option, though. Moderna’s vaccine for little kids, which is for children 6 months through 5 years old, would be administered in two doses at a lower dosage than adults. The Centers for Disease Control and Prevention has not yet weighed in on Moderna’s vaccine for children ages 6 to 17.
Asked to compare the Moderna and Pfizer vaccines for very young children at a press briefing on Friday, Dr. Peter Marks, who leads the F.D.A.’s vaccine division, said that Moderna’s vaccine might trigger an immune response “slightly more rapidly,” while Pfizer’s might “bring a greater response after the third dose.” He said parents should feel comfortable with either, and he recommended they go with whichever one is available.
Sharon LaFraniere contributed reporting.