Invasive strep A is on the rise and is affecting children in unusual ways

It was a potentially deadly form of strep A.

“We were very surprised,” Myers said. “We just don’t see this many people together in such a short time.”

An infection with Streptococcus pyogenes – or group A strep for short – usually produces mild symptoms, such as a rash, fever or swollen tonsils, leading to the eponymous strep throat. But in recent months across the United States, as well as Europe, cases linked to a rare invasive form of a common bacteria have been emerging, often in association with sometimes confusing symptoms, including skin rashes, fever, rapid heartbeat and unexplained swelling.

The first confirmed pediatric deaths in this country, in two young children in the Denver area, were reported last week. At least 16 children died from it in United Kingdomseven in the Netherlands and two in France.

The rise of invasive Streptococcus A is one of the many unusual ways pathogens are interacting with us — and each other — amid the end of social distancing and masking in the coronavirus era this year. Both World Health Organization and US Centers for Disease Control and Prevention they said they were investigating the cases, including whether a virus storm could be at least partly to blame for making so many people sick.

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Viral infections tend to disrupt a person’s immune system, making it easier for a secondary bacterial infection to take hold and amplify its effects in some cases.

Minnesota health officials said they saw 46 cases of invasive strep A in all age groups in November, more than double the average of 20 cases in previous months. Colorado reported that it is investigating not only the rise in invasive strep A cases, but also a possible rise in other severe or invasive bacterial infections in children.

Texas Children’s Hospital said it saw more than 60 patients with invasive strep A in October and November — a fourfold increase over the same period last year. James Versalovic, the medical center’s chief pathologist, said many of the affected children currently or recently had viral infections. But, he said, it is still too early to rule out other factors that could contribute to the severity of their illnesses.

“It could be that we have changed our immunity patterns due to the pandemic, which may have increased our vulnerability. But it can also be … different variants” of strep, he said. “It could be a combination of factors. Nobody knows.”

Unlike SARS-CoV-2, strep A is something people have been fighting for centuries.

It has been variously described, inaccurately, throughout history as being associated with phenomena such as comets and eclipses, or the introduction of inanimate matter into humans. It was not until 1874 that the Austrian surgeon Theodor Billroth described an organism he saw under a microscope that appeared to be grouped in chains of four or more that would later be classified as bacteria. Bacteria can live inside or outside the patient’s body, unlike viruses, which are a collection of molecules that can only replicate in the host. Both are transmitted in similar ways — through air, water, food and living things.

Several million people in the United States contract streptococcal A each year, and in our modern world, with its vast supply of antibiotics, it’s mostly a nuisance. This usually translates into a sore throat and possibly a missed day of school or work during the 24 hours it takes to stop being contagious after taking antibiotics such as penicillin and amoxicillin.

Strep A: What you need to know about the usually mild infection

“The good news is we know how to treat it and how to test for it,” said Kristin Moffitt, an infectious disease specialist at Boston Children’s Hospital who studies bacterial infections. “It’s not usually a source of serious concern that I would be overly concerned about.”

But in a small number of cases, strep A can become dangerous when it attacks parts of the body where the bacteria wouldn’t normally exist. When it enters such areas, including the blood, cerebrospinal fluid, bone marrow, and organs such as the brain and heart, it can quickly spread and kill.

The first reports of unusual activity as a result of invasive strep A, mostly involving children 5 years old and younger, came from the Netherlands between March and July. It is not only about the number of cases and their severity, said the doctors of the university preprint research paper published on December 13, but also the fact that many patients were simultaneously infected with viruses such as influenza or chicken pox. (Unlike in the United States, vaccination against varicella, which causes chickenpox, is not part of the childhood vaccination program in the Netherlands.)

During 2018 and 2019, most children seen in Dutch hospitals with invasive streptococcal A developed sepsis, systemic infection or pneumonia. But this year, many have been diagnosed with necrotizing fasciitis, a flesh-eating disease involving bacteria that destroys tissue beneath the skin. Doctors Evelien B. van Kempen, Patricia CJ Bruijning-Verhagen and their co-authors urged the public to be aware that early recognition and prompt treatment can save lives.

“Clinicians and parents should be alert and aware of unusual pediatric presentations,” they wrote.

Serious illnesses in children have also been reported in the UK, the Netherlands, France, Ireland and Sweden, but the patterns are not always the same. In the UK, doctors have reported an increase in scarlet fever – also caused by the strep A bacteria – around the same time as invasive cases. But that was not seen in the Netherlands.

Several hospitals in the United States said they were not aware of the unusual occurrence of scarlet fever in their areas.

Figuring out what’s going on in the United States is more difficult than in some other countries because of the lack of a national health care system that facilitates case tracking. CDC spokeswoman Kate Grusich said in an email that it’s too early to say whether case numbers are “just returning to pre-pandemic levels or increasing beyond what we would normally expect.”

“CDC is closely monitoring this data and speaking with surveillance sites and hospitals in multiple states to learn more about any trends,” she said.

An e-mail list for pediatricians and infectious disease specialists in this country began exploding in October with a question from a doctor in the Midwest: Has anyone else noticed an increase in invasive strep A?

The responses were mixed, as expected, given that such cases tend to be grouped together. Boston Children’s saw nothing of concern. But doctors in Kansas City, Houston and Denver did.

At Texas Children’s, Versalovic said some children came in with low blood pressure and septic shock, some with bacterial pneumonia and some with skin infections. A few were so sick that they needed intensive care. He worries that some of the cases have been missed. To diagnose invasive strep A, doctors must take samples of the patient’s blood, skin, or fluid in the lungs or other areas. But if the child needs emergency care, there may not be time to consider the cause of the illness.

Invasive strep A “doesn’t follow a simple linear progression,” he said.

In Denver, Samuel Dominguez, an infectious disease specialist at Children’s Hospital Colorado and a professor at the University of Colorado School of Medicine, said the cases he saw were “across the age spectrum” in children, noting that they may be more susceptible because the bacteria they tend to settle more aggressively in the throat and skin than in adults.

Dominguez tried to balance assurances that this is a relatively rare infection with calls to watch for warning signs.

Versalović agreed. “We don’t want to raise too much of an alarm, but these infections can progress very quickly,” he said.

Myers said all patients seen at Children’s Mercy in Missouri have recovered with treatment, but she urged parents to make sure their children have up-to-date vaccinations to prevent a viral infection that could open the door to a more serious bacterial one. “I think there are a lot of things at play that we don’t fully know yet,” she said.

One of the tricky things about the disease is that it can look so different in different children, she said. A child who has trouble moving the eyeball has had an infection of the soft tissues of the eye socket; the one with the lump behind the ear, a bone infection in that area; and the third patient, collection of pus in the back of the throat.

Myers urged parents to be careful.

“If a child seems sicker than they should be after developing a fever, it’s always a good idea to take them to the doctor if they have trouble breathing or notice anything else — even a swollen eye,” she said.