I had filled my online shopping cart with boxes of dinosaur-patterned masks, waiting to hit "buy" until I could talk to Dr. Nipunie Rajapakse. She's a Mayo Clinic physician who specializes in pediatric infectious diseases, including COVID-19.

Being a parent during the pandemic has been an exhausting and seemingly endless exercise in risk assessment — one I seem to be failing regularly. The kids are back in school, but with the rise of delta, we're not yet back to normal. It's worth remembering "the unvaccinated" in America includes 48 million children under 12 who are not yet eligible for the vaccine.

That's why I was eager to sit down with Rajapakse and ask her advice on everything from whether I should let my kids have a sleepover to which masks to buy.

Let's start with masks. How effective is mask wearing in schools?

In combination with other strategies, masking is "very effective" in preventing the spread of respiratory viruses such as COVID-19. No single strategy alone is going to be 100% foolproof, "so these strategies really work best when you use them all together," Rajapakse said.

She notes that the delta variant is more contagious than previous variants, but it's still spread in the same way. That means we need to be more meticulous about doing the things we know work: masking, hand-washing, air ventilation, distancing and vaccination for those eligible. "There's just less room for error," she said.

What should we look for when shopping for a kid's mask?

"The most important thing is making sure that the child is wearing the mask properly," Rajapakse said.

That means make sure the mask covers your kiddo's nose and mouth. Large gaping holes are a no-no.

Her next tip? Comfort. "If it's not comfortable, the child is probably not going to wear it, and the mask is sitting in their backpack at school."

Rajapakse recommends cloth or surgical (also known as medical-grade) masks that come in at least two layers.

What about N95s?

Rajapakse doesn't recommend the N95 or the similar KN95, both of which she says can be uncomfortable to wear for long periods and are primarily designed for adult facial structures.

Are there any downsides to kids wearing masks?

Rajapakse said there have not been any studies that have demonstrated any negative health consequences — there's no evidence showing they create unhealthy levels of carbon dioxide, for example. Studies on masks' effects on schooling and language acquisition have been limited but have not suggested any downsides.

Are kids getting sicker from the delta variant than from previous variants?

"It's a great question, I think one that we don't have the final answer to yet," Rajapakse said. "We do know that hospitalization rates in children, especially parts of the South that have have seen really high rates of new infections in kids, have increased."

But it's challenging to tease out whether the spike in child hospitalization rates is proportional to the increase in infected children — or if it's this variant that's making them sicker, she said.

It sounds like a vaccine for kids ages 5 to 11 might be available as early as Halloween. There have been some reports of young people experiencing myocarditis, inflammation of the heart muscle, after COVID-19 vaccination. Given that most children aren't seriously sickened by COVID-19, how should parents weigh the risks of vaccination?

Rajapakse said the risks of getting heart inflammation or multisystem inflammatory syndrome inchildren (MIS-C) as a result of a COVID-19 infection is higher and tends to be more severe than the risk of getting either of those conditions from the vaccine, even in teens. She's also seeing more reports of teens with long COVID-19 symptoms, even if their initial infection was mild.

"'Taking your chances' with COVID infection" is not a reasonable approach, based on current data and especially with the high rates of transmission in many places around the country, she said.

You're expecting your first child in December. What advice do you have for pregnant people who are hesitant about getting the vaccine?

Multiple studies have now been published demonstrating COVID-19 vaccines are safe and very effective in women who are pregnant, breastfeeding, or planning to become pregnant, Rajapakse said. There is no increased risk of miscarriage or infertility.

Rajapakse received both doses of the vaccine in January, two months before she got pregnant. Initially, pregnant people were intentionally excluded from the clinic trials for the vaccine. But, she says, we "now have lots of real-world experience and data that has been very reassuring."

How safe is it for kids to be playing indoor sports?

Some sports, like baseball, have physical distancing inherently built into them. Rajapakse suggests considering the following: How many kids are on the team, and how close in proximity are they to one another? Some teams and schools have adopted strategies like routine testing to reduce the odds that a player is infected.

Remember, what happens off the court or field matters, too. Team dinners and other social activities may represent "the higher-risk part of sports participation than the actual game itself," she said.

What happens if my kid gets a runny nose? Do they need to stay home?

Yay! You've demonstrated what Rajapakse calls "a high index of suspicion of new symptoms." Contacting your family's health care provider is a reasonable first step, as is getting your child tested for COVID-19. While you wait for results or an available slot to talk to your provider, she says, keep the kid home.

"Pre-pandemic, you might not have thought twice about sending them to school with a bit of congestion or a runny nose," she says. "But we know that kids can spread the virus even if they have mild symptoms or no symptoms at all."

What about sleepovers and indoor playdates?

Being in close proximity indoors to someone who is infected for longer periods of time increases your chance of getting infected, Rajapakse cautions. On the other hand, children need social interaction. You can reduce the risk of indoor playdates and sleepovers by keeping your "social bubble" small, she says.

Should unvaccinated children be spending time with their unvaccinated grandparents?

"That would be quite a high-risk situation that I would definitely try and avoid," she said. Unvaccinated children who are carrying the virus are more likely than adults to present with few or no symptoms, and unvaccinated grandparents who are infected are at risk for severe illness, hospitalization or death.

If the grandparents are vaccinated, that lowers the risk of them being seriously sickened with COVID-19, she said.