The U.S. Centers for Disease Control and Prevention has recommended the COVID-19 vaccine for children ages 5 to 11, and CDC Director Dr. Rochelle Walensky officially gave the green light on that guidance Tuesday. This development follows the U.S. Food and Drug Administration approval last Friday of emergency use authorization for Pfizer-BioNTech's vaccine for that age group. This cohort of younger children can begin receiving these shots as early as this week.Grown-ups have a lot of questions. What dose are their kids getting, and how long will it take to kick in and protect their children? What side effects should they expect? What if their child is about to turn 12 — should they wait until then to get the higher dose? And what happens if the pediatrician's office doesn't have vaccine appointments — what other options are there to get a shot?CNN Medical Analyst Dr. Leana Wen, the mother of two young kids, an emergency physician and professor of health policy and management at the George Washington University Milken Institute School of Public Health, is answering those questions.Q: What dose of the Pfizer-BioNTech vaccine did the FDA and CDC authorize for children ages 5 to 11, and how long will it take for kids to be considered fully vaccinated?Wen: The dosage authorized for this younger age group is 10 micrograms, which is one-third the dose given to adults and kids age 12 and older (30 micrograms). Similar to how it's administered to older individuals, the vaccine is given in two doses, spaced at least 21 days apart. Kids are considered fully vaccinated two weeks after they receive the second dose.Q: What kind of side effects should kids expect?Wen: In the clinical trial involving more than 3,000 kids 5 to 11 years old who received the vaccine, side effects were similar to the kinds seen in adults. The most common side effects are soreness at the injection site, fatigue and headache. Some children can experience fever and chills. All of these side effects subside within a couple of days. In fact, the risks of these side effects were lower in the younger kids than in adults — probably because of the lower dose.In the clinical trial, there were no cases of myocarditis, or inflammation of the heart muscle, that is seen in very rare cases, predominantly in older children and adolescents. This condition is, in theory, still a possible risk, but expected to be extremely rare. The chance of myocarditis from COVID-19 is expected to be higher than the chance of myocarditis from the vaccine.Some parents may be worried about long-term side effects. There is no scientific reason to think that this would happen. Side effects from other immunizations occur within the first two or three weeks following the shots, not months afterward.Q: Should parents and families plan on kids missing school to recover from potential side effects after they get the vaccine?Wen: That's up to you. A lot of kids have minimal side effects and will have no problem going to school the next day. On the other hand, if you are worried about childcare, in case your child has to miss school and then you may have to miss work, it's reasonable to schedule the shots on a Friday or weekend.Q: Can a child get the COVID-19 vaccine the same time as another vaccine, like the flu vaccine?Wen: Yes. If given at the same time, the vaccines would be given in a different injection site — for example, in the other arm, or in two different places on the leg.Q: What if a child has a history of food or medication allergies? Should they skip this vaccine?Wen: No. The only reason not to get this vaccine is if your child has a severe allergic reaction to one of its components. Note that the COVID-19 vaccines do not contain egg products, as some other vaccines do. If your child has a food allergy or had a reaction to another vaccine in the past, that is not a reason to refrain from the COVID-19 vaccine.If you are particularly concerned, mention it to your pediatrician or pharmacist. These health professionals can observe your child in the office or pharmacy for longer following the vaccine just to make sure there is no allergic reaction.Q: Should a child who has had COVID-19 before still get vaccinated?Wen: The CDC recommends that individuals who previously were diagnosed with COVID-19 still get vaccinated. The vaccine provides additional, longer-lasting protection than recovery from illness.There are some experts who believe that someone who has had COVID-19 only needs one shot of the vaccine. However, this is not the CDC recommendation, which is to receive two doses of the vaccine regardless of prior infection.Q: What about healthy kids — should they still be vaccinated?Wen: Yes. About one-third of the children who have been hospitalized from COVID-19 are those with no underlying health conditions. Healthy children can become very sick from coronavirus and would also benefit from the vaccine.Q: What happens if the pediatrician's office says their appointments are already booked?Wen: I know a lot of parents are very eager to get their kids vaccinated — I would be, too, if my kids were old enough! I'd first ask the pediatrician's office when their next appointments will be. Are we talking a matter of waiting a few days or multiple weeks? If it's just days, I'd wait, but if it's weeks, I'd ask to be put on the waitlist and then call around to explore other options.Call all your local pharmacies, both chains and independent pharmacies. Make sure to mention your child's exact age, as some places may not give shots to young kids. If they are not sure yet, call back the next day — a lot is changing very quickly. Your local health department may have information on vaccine clinics. And ask your school administrator and other families, too, for recommendations.Q: We get this question a lot — should families with 11-year-olds wait until their kids turn 12 to get the higher dose, or go ahead and get the lower dose now?Wen: This was an extensive topic of conversation at the CDC meeting on Tuesday. The CDC recommends that children receive the appropriate dose for their age at the time of inoculation. If a child is just about to turn 12, they could get the 10-microgram dose for their first dose and the 30-microgram dose for the second.It's important to note that vaccines are not weight-based. The 10-microgram dose, in the younger age group, was found to be optimal when it comes to both effectiveness and lower side effects. In the older age group, the 30-microgram dosage is what was studied. There probably isn't a major difference for an 11 or 12-year-old to get 10 versus 30 micrograms.Q: Is there any reason to wait for the Moderna vaccine or Johnson & Johnson in this age group?Wen: No. These other vaccines are not authorized for emergency use in this younger age group, and, in fact, the data has not even been submitted for federal health officials to review. It may take months for the FDA and CDC to review those applications. I would highly recommend that you vaccinate your children with what is available now, which is a safe and highly effective vaccine from Pfizer-BioNTech.Q: Should parents with children younger than 5 still take additional precautions, even after an older sibling is able to be vaccinated?Wen: Yes, because there will still be a child in the house who remains too young to be vaccinated. That said, families can decide that once an older child is vaccinated, he or she can resume some activities that were put on hold before. A sleepover with others who are fully vaccinated, for example, is now much lower risk, as are sports and extracurriculars with other vaccinated kids.Q: What would you say to people who don't believe COVID-19 is a real threat to children?Wen: I'd refer them to the data. There have been more than 1.9 million cases of COVID-19 in this younger age group, according to the data presented at the CDC meeting. More than 8,300 children have been hospitalized. There have been over 2,300 cases of multisystem inflammatory syndrome in children, or MIS-C, which could cause severe organ damage with long-term consequences. COVID-19 is now one of the top 10 leading causes of death in this age group.We now have a vaccine that is over 90% effective at preventing COVID-19 in younger children. All of us want to do what's best for children. I hope parents and families will take advantage of this free and safe vaccine, giving our kids protection — and adults much-needed peace of mind.