The CDC Is Investigating a Rise in Invasive Strep A Infections Among Kids—What to Know

The Centers for Disease Control and Prevention is investigating an increase in invasive group A streptococcal (iGAS) infections among children, the agency announced last month.

In a CDC health advisory shared on December 22, the agency noted an increase in pediatric iGAS infections at a hospital in Colorado, where there had been at least 11 reported iGAS cases since November 1. Other states, including Minnesota and Pennsylvania, have also reported potential increases in iGAS cases.

The United Kingdom, too, reported an uptick in iGAS infections among children; so far during the 2022–2023 season, there have been 652 notifications of iGAS disease reported in England.

The increase in pediatric iGAS infections comes at a time when other respiratory illnesses—including respiratory syncytial virus (RSV), flu, and COVID-19—are circulating at higher levels.

Though the CDC said the overall number of pediatric iGAS cases remains low—and that infections are still rare in children—the advisory still urged the importance of early recognition, diagnosis, and treatment in both children and adults.

Invasive Group A Strep Infections, Explained

Bacteria called Streptococcus pyogenes—also known as group A Streptococcus or group A strep—can cause a wide range of conditions, including invasive and noninvasive disease.

Strep throat, formally known as acute pharyngitis, is an example of noninvasive group A strep disease, which is typically mild but very contagious. Strep throat causes an estimated 5.2 million outpatient visits each year in the U.S. Scarlet fever and impetigo are also noninvasive group A strep diseases.

But, rarely, some group A strep infections can cause invasive disease, meaning the bacteria bypasses the immune system and invades certain parts of the body—including muscle, fat, lungs, and the bloodstream—that are normally free of germs. In the past five years, the U.S. has reported an annual 14,000–25,000 iGAS cases. Between 1,500–2,300 people die from iGAS diseases each year.

“The one reassurance I give parents is that invasive group A strep infections are rare,” says Anthony Flores, MD, MPH, PhD, chief of pediatric infectious diseases at UTHealth Houston and Children’s Memorial Hermann Hospital. “The most common group A bacterial infection is noninvasive and those frequently cause a sore throat in kids and young adults.” 

While noninvasive infections typically clear up on their own or with treatment within a few days, iGAS infections can erupt into serious illnesses that demand immediate medical attention, said Dr. Flores. These iGAS diseases include cellulitis, necrotizing fasciitis, pneumonia, and streptococcal toxic shock syndrome (STSS).

According to Dr. Flores, parents should closely watch children for symptoms that could indicate an iGAS infection, including:

• Fever
• Severe pain and swelling
• Redness around a open sore or wound
• Dizziness
• Confusion
• Low blood pressure
• Skin rash
• Abdominal pain

“[These] are still relatively rare complications but you want to do everything you can to protect your kid and yourself because it can absolutely infect adults as well,” Sheila Nolan, MD, an assistant professor of pediatrics and chief of pediatric infectious diseases at New York Medical College, told Health.

Vaccination Lowers the Risk of iGAS

Group A strep bacteria can spread through respiratory droplets or direct contact with secretions or open sores from an infected person. Risk factors for iGAS include a weakened immune system, chronic illness, age, or recent skin injuries that result in open wounds or sores.

But there’s no perfect way to predict whether a sore throat or a superficial skin infection will manifest into a more serious complication. “Predicting a child’s clinical course can be challenging,” said Dr. Flores. “A majority of kids recover just fine without treatment, but in some [rare] worst-case scenarios there are kids who were fine one day and then the next in the ICU on a breathing machine.” That is still considered the exception, not the rule, added.

Children specifically are better at spreading the bacteria, since they’re less likely to practice good hygiene—like coughing directly into their hands and not washing them properly—said Dr. Flores. But keeping everyone (kids especially) up to date on vaccinations can help lessen the spread.

The COVID-19 pandemic, however, has likely indirectly contributed to the higher volume in iGAS cases. Although safety precautions kept many people safe from contracting the coronavirus, Dr. Nolan said one drawback was that a lot of children did not stay up to date with their vaccines.

Additionally, vaccine hesitancy and misinformation on the COVID-19 shots have lowered parents’ confidence for other immunizations. According to the World Health Organization, the COVID-19 pandemic caused the largest drop in childhood vaccinations in the past 30 years.

The CDC is urging all parents to make sure their children are up to date on two vaccines in particular: chickenpox and flu. Dr. Flores explains that chickenpox causes open sores, which are perfect opportunities for bacteria like group A strep to creep inside the body and travel to the bloodstream or deep tissue. “When we started vaccinating against chickenpox, we saw a dramatic decrease in how often we saw invasive group A strep infections in kids.”

Having the flu increases the risk for complications if you are exposed to group strep A bacteria. Research suggests the flu virus interferes in the immune system’s antibacterial response. The decreased inflammatory response gives opportunity for group A strep bacteria to enter the bloodstream or lungs undetected. This increases the risk for a bacterial superinfection—a second infection from a different microbial agent on top of another one.

“If we can prevent major symptoms from influenza, we can reduce the risk we will see invasive group A strep infections as well,” said Dr. Flores.

Dr. Nolan added that even if you get exposed to iGAS bacteria, vaccinated individuals tend to have more mild disease and are unlikely to get pneumonia or other complications.

Antibiotics Are the Best Treatment for iGAS

Most commonly iGAS infections are treated with antibiotics, which dramatically reduce the amount of bacteria spreading in the body. According to Dr. Flores, oral antibiotics like amoxicillin and penicillin are highly effective with no signs of antibiotic resistance from the bacteria.

In more severe cases, children with iGAS infections may also need to be hospitalized. “The kids with more difficult or severe infections are the ones that come in with a lot of other symptoms,” said Dr. Flores. “It’s really just supportive care in addition to the antibiotic treatment.”

The current shortage of liquid amoxicillin—the preferred treatment for iGAS infections—may cause additional complications for treatment. But experts say other antibiotic options are available.

Amoxicillin comes in many forms, according to Behnoosh Afghani, MD, a pediatric infectious disease expert at UCI Health. Doctors often prescribe liquid amoxicillin to children because it’s easier to ingest than swallowing a pill, but she says taking amoxicillin through an IV is just as effective. There’s not currently a shortage of penicillin, which works similarly to amoxicillin—penicillin is just an older option and does not treat as many bacterial strains.

Depending on the severity of the infection, another antibiotic called clindamycin may also be prescribed. “The good thing about clindamycin is that it has good bioavailability,” Dr. Afghani told Health. “This means that if you take it by mouth, most of the drug goes to the blood instead of sitting in the gut.” She says oral or IV clindamycin would be best paired with penicillin for treatment of invasive group A strep infection.

If you suspect your child has a group A strep infection, healthcare providers recommend calling your pediatrician. If symptoms worsen, do not delay in going to the emergency room to get proper treatment as quickly as possible.