One chart shows the differences between the 2 COVID vaccines available for young kids, from side effects to dosing

• Vaccines are now available for babies as young as 6 months old in the US.
• There are two brands being offered: Pfizer and Moderna.

The littlest COVID-19 vaccines are here.

Babies and toddlers as young as 6 months old started receiving COVID-19 vaccines in the US this week, after the Centers for Disease Control and Prevention gave the shots the final green light over the weekend.

Parents and caregivers have two different vaccine brands to choose from: Pfizer and Moderna. While both vaccines work, they're not exactly the same thing.

Pfizer's three-shot vaccine course uses a smaller dose of mRNA, and has less frequent side effects, while Moderna's two-shot vaccine course is both shorter and faster-acting.

Here's everything you need to know about the two different vaccines, including how they compare when it comes to dosing, side effects, and protection:

The data here are based on vaccine trials conducted by the two drugmakers for regulatory approval. Moderna tested its low-dose vaccine on more than 5,000 kids, while Pfizer's trial included more than 3,000 young participants.

Many doctors and public health experts are already expressing a preference for Moderna's shot, and one of the biggest reasons they like it better is because protection kicks in several weeks faster than Pfizer's does, with fewer jabs.

It's fine to vaccinate a kid who was recently infected with COVID

Most children in the US have been recently infected with COVID-19, but experts caution that the immunity gained from those Omicron infections may not be very durable or long lasting. Vaccines can still help little ones develop a robust immune response against the virus in all its forms. And, many studies also show that vaccinated people may be less likely to get reinfected with COVID again (because of what's called "hybrid immunity.")

If you're wondering when to vaccinate your child who recently had COVID, public health expert Katelyn Jetelina, who runs the popular newsletter Your Local Epidemiologist, says don't "overthink it."

While you can wait up to three months after a COVID infection to get the vaccine, the CDC says as long as a person has recovered from their illness (generally, that takes 10 days or less), it's fine to go ahead and get vaccinated.

"If they're done with their infection, and it's been about 10 days, and their symptoms are getting better, I, as a parent would go get them vaccinated right away," Jetelina said. "Figuring out the timing for the next wave is a slippery slope to go down, and I think that it's just more straightforward for people to get vaccinated as soon as they can."

Most importantly, vaccines help people of all ages stay alive, and out of intensive care. Even though the number of children who've died from COVID-19 is small in the grand scheme of this fatal pandemic, the virus has still become a leading cause of death for kids from 0-4 years old.

Jetelina, a mother of two young girls who both recently had COVID, said that for now she's "with every other parent, trying to scramble to find an appointment" to get her kids vaccinated.

"Honestly, I'm going to be waiting for Moderna, even if that's another day or two," she said.

Still, she acknowledged that "there is a pro to Pfizer" — the lower incidence of side effects.

"To some parents, that may be a great reason to go with Pfizer instead of Moderna."