Children under 5 years old infected with the Omicron variant of COVID-19 are presenting with symptoms of croup, an upper airway infection that causes a barking cough, pediatricians have recently reported.
Croup isn't an uncommon diagnosis in kids ages 6 months to 3 years, and most cases are mild and treatable. With Omicron impacting young, vaccine-ineligible children at -- especially in comparison to previous strains of the virus -- pediatricians are noticing an increase in patients with croup-like symptoms who test positive for COVID-19.
Experts suspect that this overlap could be Omicron-specific. has shown that this variant infects the upper respiratory tract and has a harder time getting into the lungs, unlike previous variants.
Eric Ball, MD, a pediatrician at Children's Health Orange County in Southern California, told that COVID-19 cases started to spike in his young patients just before Christmas. His older, vaccinated patients generally come in with mild symptoms, he said. But for children under 5, the disease appears to be more serious.
"Croup is one of many things that we are seeing these kids present with," Ball explained. "But, as a general rule, the people who have not had vaccines, which largely are the little children, are getting sicker than the people who have been vaccinated and have some protection against COVID."
Ball has admitted more children to the hospital for COVID-19 in these first weeks of 2022 than he did for all of 2021, he added. As of January 10, he said he was on his sixth admission.
This increase in hospital admissions for COVID-positive children with symptoms of croup has also been seen at Children's Hospital Los Angeles (CHLA).
"In general, we don't get a lot of hospitalizations for croup. It's something that usually we can manage in the emergency [department] and we might have a handful of hospitalizations," Susan Wu, MD, a pediatric hospitalist at CHLA, told . "But I have seen several patients admitted with croup due to COVID in the last couple of weeks. ... That is unusual."
Omicron may look like croup in young kids because of how similar the symptoms are: barky cough, difficulty breathing, often a fever, she noted. For Wu and other pediatricians, recognizing that croup can be a possible symptom of COVID is crucial; a heightened awareness of this may urge parents to take more caution, potentially preventing the spread of COVID-19 to other young children, grandparents, or immunocompromised family members.
With many schools returning to in-person learning this month, Wu said she is preparing to treat more pediatric COVID cases.
"We know that [the Los Angeles Unified School District] has robust policies regarding vaccinations and masking, but we know Omicron is very contagious," she said. "So we've remained ready to take care of any additional kids that may become infected with the opening."
In an interview, Daniel Rauch, MD, chief of pediatric hospital medicine at Tufts Children's Hospital in Boston, pointed out an especially odd development: many kids with COVID who are over the typical croup age are presenting with croup-like symptoms.
"It's unusual just because of the physics of it. The airway is bigger, so you don't typically see croup in older kids," Rauch told . "So, it was a little surprising that we had a couple of kids hospitalized with croupy symptoms in that age group who turned out to have COVID."
At the end of December, a patient as old as 9 came in with croup and then tested positive for COVID, he said, noting that he was unable to confirm if the patients over 5 with croup were vaccinated.
Aaron Milstone, MD, a pediatric infectious disease expert at Johns Hopkins University School of Medicine in Baltimore, said it's too early to tell whether the presentation of croup in kids with COVID is unique to Omicron -- but he believes that it is.
"There are two options: one is that this variant is different, and it's affecting the respiratory tract of kids differently. And the other option is that earlier variants may have also caused croup, but there just weren't as many pediatric cases of COVID so it didn't get brought to people's attention," Milstone said. "But I think it's more likely that Omicron is different, and this is a variant-specific presentation."