Group A streptococcus is a type of bacteria that can cause a range of illness—from strep throat and scarlet fever to skin infections. An invasive case of strep A refers to when the bacteria spreads to parts of the body that it doesn’t normally reach, such as the bloodstream. According to the CDC warning, this can cause severe and even fatal illness and requires immediate treatment with antibiotics. As of writing, at least two kids in the U.S. and 21 in the U.K. have died as a result of contracting the infection, per TODAY. The U.K. Health Security Agency said in an advisory last week that cases tend to rise sharply in the new year but appear to have spiked earlier than expected, an unfortunate reality that was also experienced this year with the rise in RSV and influenza cases. Children’s hospitals in Arizona, Colorado, Texas and Washington apparently reported a higher-than-average number of cases this season compared to past years. “While the overall number of cases has remained relatively low and (invasive Group A strep) infections remain rare in children, CDC is investigating these reports,” the agency said. It also added that in some parts of the country, the increase in strep A is occurring at the same time as “increased circulation” of respiratory syncytial virus, influenza, COVID-19 and other respiratory viruses. Noninvasive illnesses from strep A, according to the CDC, include strep throat, scarlet fever, and Impetigo, while much more serious conditions that result from an invasive strep A infection include Cellulitis with a blood infection, Pneumonia, Necrotizing fasciitis (popularly known as flesh-eating disease), and Streptococcal Toxic Shock Syndrome (STSS), “which can develop very quickly into low blood pressure, multiple organ failure, and even death,” per the official communication. Strep A is spread through contact with droplets from an infected person when they cough, sneeze or talk. Cases of Group A strep tend to follow a seasonal pattern, peaking between December and April in the U.S. It’s most common in kids 5 to 15 years old. Signs of a Group A strep infection, per the Colorado Health Department, include:

Sore throatFeverChillsNew rashesSkin bumpsPainful red patches on the skin

Signs a child’s strep A infection may be invasive include:

A change in mental status. “Maybe you’re not able to arouse the child, or the child may not be responding normally,” Dr. Ethan Wiener, chief of emergency medicine at NYU Langone Health Hassenfeld Children’s Hospital, told the news outlet. “That’s different from the child feeling blah or lying on the couch all day.”Early signs of necrotizing fasciitis, which, per the CDC, include: a red, warm or swollen area of skin that spreads quickly; severe pain, including pain beyond the area of the skin that is red, warm, or swollen; fever. Later-stage signs are: ulcers, blisters, or black spots on the skin; changes in the color of the skin; pus or oozing from the infected area; dizziness; fatigue; diarrhea or nausea.Early signs of streptococcal toxic shock syndrome, which, per the CDC, include: fever and chills, muscle aches, nausea and vomiting. Later signs, which usually develop 24 to 48 hours after the first symptoms, include: low blood pressure; faster than normal heart rate; rapid breathing; signs of organ failure, such as inability to produce urine or yellowing eyes.

High fever and labored breathing, as well as “difficulty coordinating swallowing with breathing” in young kids, “should trigger parents to call their provider or to seek emergency care, depending on the seriousness of the situation,” Dr. Ishminder Kaur, a specialist in pediatric infectious diseases at the UCLA, David Geffen School of Medicine, told TODAY. In addition to getting the chickenpox vaccine and flu shots, to prevent strep A infections, the CDC recommends washing your hands often for at least 20 seconds or using an alcohol-based hand sanitizer, especially after coughing or sneezing and before preparing food or eating. You should also cover your coughs and sneezes with a tissue and dispose of it right away, or use your upper sleeve or elbow as a last resort—never your hands—to help prevent the spread of germs. However, as always, when in doubt about your child’s condition, seek professional medical care. For more in-depth information, visit the CDC’s website.