The back-to-school guide for fighting common viruses - Popular Science

Having a sick kid is no fun. Fortunately, even though the viruses that are common in childhood can pack a punch, these not-exactly-alive microorganisms are almost always defeated by soap, masks, open windows, and vaccines. Still, kids get sick a lot. And once they get better, it's on to the next bug.

"Kids tend to get a lot of infections because their immune system is naive in comparison to an adult who might have encountered some of these viruses before," says Kishana Taylor, a post-doctoral researcher at Rutgers University–Newark who co-founded the Black Microbiologists Association. That's why it's so important for little ones to get vaccinated: Even when they haven't been exposed to a virus, they're still protected. Getting vaccinated can also stop a child from getting sick, and keep them from infecting classmates, school staff, and their families. Or if they do get sick, they'll have an easier time of it. 

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You should probably call a doctor if a child or teenager has any of these symptoms: a high fever, neck pain, shortness of breath, and lethargy (that is, significantly less energy than usual). Parents and guardians "know their kids the best," says Jorge Moreno, a physician and assistant professor of medicine at Yale School of Medicine. "Calling the pediatrician's office early can provide some more specific advice for the child," he adds. "If the call or visit is delayed, the child's illness may be more severe, and may require an urgent visit to the emergency room."

Here's what you should know about the most relevant childhood viruses.

SARS-CoV-2

What's this virus? As a respiratory virus, SARS-CoV-2 spreads when an infected person is, as you might guess, coughing or sneezing. Talking, laughing, and singing spread the pathogen, too: It's all due to the little droplets you make when you open your mouth and breathe. And it's very common in children, who account for about 1 in 5 cases in the US. 

Though COVID-19, which is caused by the SARS-CoV-2 virus, is typically a mild illness for children, some people in their lives—grandparents, for example—are at a higher risk.

Prevention advice: According to the CDC's COVID-19 vaccine guidelines, children as young as 6 months can be vaccinated, either in a three-dose or two-dose series, depending on age. Boosters that protect from Omicron subvariants will also soon be available for ages 12 and older.

Masks are another option. Basically, viruses hate them. Children over the age of 2 are able to wear masks. As Canada's Chief Public Health Officer Theresa Tam recently noted, if a child is comfortable wearing masks, they should stick to them. 

"I would say the riskiest behavior that parents can have any control over is going to be not masking while indoors," Taylor says. 

If a child practices good hygiene and gets vaccinated, it impacts the entire community: teachers, bus drivers, janitors, and those with a compromised immune system. It's not just about protecting the child and their family—it's protecting anyone that child has come into contact with, too.

Influenza viruses

What's this virus? Influenza—the flu—is everywhere, and it can lead to serious complications in children. Each year from 2010 to 2020, between 7,000 and 26,000 children were hospitalized for the flu in the US, the CDC estimates. Kids under 5 are vulnerable to serious complications, and toddlers and infants are especially at risk. 

Children can die from the flu, though it's quite rare. According to the CDC, from 2004 to 2020, between 37 and 199 deaths were reported during the flu season–with the exception of the 2009 H1N1 pandemic, when 358 pediatric flu-related deaths were reported. (That's likely an undercount, the health agency says.) Children who weren't vaccinated for the flu accounted for 80 percent of these deaths. 

[Related: The surprising ways your immune system adapts to the flu virus you got as a kid]

Like SARS-CoV-2, this is a respiratory pathogen. It spreads the easiest indoors, which is why we call the fall and winter flu season. Viruses are weaker outdoors: They don't like the beach, where breezes quickly disperse any microbes that people breathe out.

Prevention advice: To prevent infection, children can get a flu shot at a doctor's office or pharmacy. Your local school might be organizing a vaccine clinic day, too. The CDC recommends kids get a flu vaccine every year, ideally before the end of October. Even toddlers and infants can get a flu shot, as long as they're over 6 months old. And there's good news for kids (and adults) who can't handle needles: it's not just a flu "shot" anymore. A nasal spray vaccine is available for most people over 2 years old. "Watch out for flu vaccines coming in the next few weeks," Moreno says.

To slow the spread, sanitize and wash your hands. Do it often—probably more often than you think you need to. And if you have to sneeze or cough, don't do it into your hands. Crook your arm and put your mouth near your elbow, not your hands. As Sesame Street says: Sneeze in the bendy place. (The dance move dabbing may not have a kid-friendly origin, but it's a fun way to practice sneezing safely!) Another way to explain it to kids: Be a vampire hiding behind a cape.

Rhinoviruses

What's this virus? The common cold is a respiratory infection that is caused by a rhinovirus. Sometimes, symptoms are not just a sneezy, sniffly mess: Rhinoviruses can lead to painful ear infections. A sinus infection can happen, too—they're typically due to viruses. (Influenza and parainfluenza can cause this acute facial pain, as well. And, by the way, though most sore throats are caused by viruses, a strep throat isn't: group A Streptococcus bacteria are to blame.)

Prevention advice: Unlike the flu, which is typically more severe, we don't have a vaccine for the common cold. We do have the power of soap, of course. Wash your hands often, and help your kids do the same. Don't touch your face. Distance yourself from anyone who seems sick. And don't forget the vampire sneeze!

Also, any room where groups gather should be adequately ventilated. This could be as simple as keeping windows and doors open. Depending on the district or the school, "you may be allowed to provide an air purifier or Corsi-Rosenthal box, but mileage may vary," Taylor says.

Measles, mumps, rubella, and chickenpox

What's this virus? These highly contagious illnesses are grouped together because they can be immunized at one time. Measles, in particular, can be serious or even fatal in children, especially in kids under 5. But fatal cases are rare: For every 1,000 children with measles, 1 to 3 will die from complications, such as pneumonia.

Prevention advice: Unlike the common cold, we have vaccines for these illnesses . There are two options: the MMR vaccine (measles, mumps, and rubella), which children can get starting at 12 months; and the MMRV vaccine, which tackles the virus that causes chickenpox (varicella zoster). Infants should get the first dose between 12 and 15 months of age, and the second dose anytime between ages 4 and 6.

Monkeypox

What's this virus? At this point, it is very unlikely that a US child will be infected with monkeypox, the American Academy of Pediatrics says. Only a handful of pediatric cases have been confirmed in the US. 

Like chickenpox and hand-foot-and-mouth disease, monkeypox causes a red, blistery rash. That rash is reportedly quite painful and itchy, and it typically goes away within four weeks.

[Related: How to talk with your kids about the COVID vaccine]

It spreads via prolonged face-to-face interactions (without masks), contact with an infected person's rash or scabs, and contact with items they have touched, such as blankets and towels. Hand-foot-and-mouth disease is also spread through stool and saliva, which is why hand washing is so important. 

Prevention advice: Some schools are preparing for potential outbreaks using CDC guidelines, which state that "settings should follow their everyday operational guidance that reduces the transmission of infectious diseases." That means disinfecting surfaces, offering personal protective equipment (PPE) to staff who care for children who have been infected, and encouraging community members to wash their hands and stay home when they feel sick. Children with this rash should do their best to not scratch (an almost impossible task!), keep the spots covered, and not touch their eyes.

Norovirus

What's this virus? This contagious stomach bug leads to a variety of "tummy issues," such as diarrhea, vomiting, nausea, and more. (It's not the flu, though, and it's not food poisoning, either.) 

Prevention advice: The virus spreads through contaminated foods, water, and surfaces, so make sure to wash your hands, especially before touching food! To help others stay healthy, the CDC says that children should stay home when they're sick, and for two days after symptoms subside.

Poliovirus

What's this virus? Poliovirus—a very contagious virus that spreads through fecal and respiratory contact—presents a serious risk for children under 5. It can paralyze a child, or even kill them.

Prevention advice: There is no polio cure. But there is a vaccine, which is so effective that the disease was nearly wiped off the planet decades ago. This may be changing, however: Though over 92 percent of children under 2 have been vaccinated for polio, vaccination rates vary across the country. New York reported one new case in July. "The best next step would be for parents to check with their pediatrician if their children are up to date with their vaccines, including the polio series," Moreno says.