What New Parents Should Know About Parechovirus

Health & Wellbeing

Health officials warn that this common, but little-known, virus can pose a lethal threat to infants.

About two weeks after he was born, Kat DeLancy’s son, Ronan, became fussy and stopped eating as well as he had been.

Ms. DeLancy, 34, hoped it was colic. But Ronan also developed a flat, red rash on his chest. So Ms. DeLancy, who lives with her husband and toddler in Connecticut, took her baby to the pediatrician. He had no fever and his vital signs looked good, the doctor said. She thought it might be gas and suggested that Ms. DeLancy, who was breastfeeding, try cutting dairy from her diet.

Later that evening, however, Ronan seemed even more tired and feeding him felt forced. Ms. DeLancy called her pediatrician’s office again and though she was reminded that Ronan had been cleared just hours before, she was advised to trust her gut and bring him to the emergency room. She hoped she was overreacting, but at the hospital, clinicians quickly discovered the baby’s oxygen levels were plummeting and he began having seizures.

Four days later — after a slew of tests and scans revealed Ronan had significant swelling in parts of his brain — Ms. DeLancy and her husband, Mitchell, finally got an explanation for Ronan’s sudden illness: He had parechovirus, a common pathogen that usually causes mild, cold-like symptoms or no symptoms at all. But in rare instances — particularly among infants — it can cause severe illness and irreparable brain tissue damage, as was the case with Ronan. He died in his parents’ arms, 34 days after he was born.

Last week, the Centers for Disease Control and Prevention issued a health alert notifying doctors, nurses and public health departments to the fact that the virus has been circulating nationally since May. The C.D.C. is urging clinicians to consider it as a possible diagnosis for any babies with unexplained fever, seizures or sepsis-like symptoms.

After Ronan’s death in June, Ms. DeLancy chose to share her family’s story with news outlets to get the word out about this little-discussed virus.

“We were so blindsided,” said Ms. DeLancy, whose family had been “incredibly cautious” about Covid before Ronan’s birth, limiting outside contact and being so diligent about masking that her co-workers (Ms. DeLancy works as a clinical dietitian) affectionately teased her efforts.

In the hospital, where she watched over her baby, who was hooked up to a ventilator, she repeated the same questions over and over: “How is this happening? What did I miss?”

There are four species of parechovirus, and within those there are several different types. According to the C.D.C., the virus is so common that most children have been infected by the time they start kindergarten.

“Parechoviruses are part of a larger group of viruses called the enteroviruses, and all of these viruses cause pretty much the same symptoms,” said Dr. Kenneth Alexander, chief of infectious diseases at Nemours Children’s Hospital, Florida.

Those symptoms are very similar to what people experience with a common cold: A sore or scratchy throat, runny nose, coughing, sneezing, “that kind of thing,” Dr. Alexander said.

Yehyun Kim for The New York Times

Other common symptoms of parechovirus include fever, nausea, vomiting or diarrhea, and a viral rash.

“For the most part, parechovirus causes illness that tends to be very mild,” said Dr. Ami Patel, an attending physician in the division of pediatric infectious diseases with the Ann & Robert H. Lurie Children’s Hospital of Chicago. “Very rarely do we get more severe illness.”

There have, however, been case studies of severe illness caused by parechovirus in babies in the United States, including one in which a baby’s most prominent symptom was a severely distended abdomen.


Babies under 3 months old — and especially those under 1 month — are more likely to experience severe illness, the C.D.C. alert warns. They have not developed immunity to the virus, which can spread through contaminated surfaces or through the air.

“The virus can cross the blood-brain barrier and cause inflammation in the wrapping around the brain, the meninges, or even inflammation in the brain tissue itself,” Dr. Alexander said. These conditions are known as meningitis (swelling of the membranes covering the brain and spinal cord) and encephalitis (inflammation of the brain).

That was the case for Maddison Hood’s son Waylon, who started showing symptoms of parechovirus when he was about 3 weeks old.

“I noticed he wasn’t feeding like he normally would. It would take him a long time to finish a bottle, and he didn’t want to nurse,” said Ms. Hood, 27, who lives in Texas. “His color looked off to me. He looked pale.” Waylon was born on March 26, six weeks before his due date, but until that point had been a healthy newborn who spent his time eating and sleeping.

Ms. Hood immediately took Waylon to the family’s pediatrician, who said his temperature and oxygen levels looked fine, but was also concerned about his paleness; she urged Ms. Hood to go to the hospital, where Waylon’s condition deteriorated rapidly. Waylon’s temperature dropped and he struggled to breathe. He began having seizures that took days to get under control. Doctors took M.R.I.s and checked Waylon’s spinal fluid, which came back positive for parechovirus. On April 28, Waylon passed away.

Like Ms. DeLancy, Ms. Hood shares Waylon’s story to help prevent further loss. There is no treatment for parechovirus, although having a diagnosis can change how doctors try to manage the illness, and provide answers to families.

And families can try to prevent infection by taking the precautions they typically do with a newborn in the home: washing hands frequently and limiting visits with anyone who is unwell.

But Ms. Hood does not want to worry other parents. Instead, she hopes her family’s story will empower other parents to take changes in their babies’ eating or appearance seriously. The American Academy of Pediatrics emphasizes that fevers in young babies always warrant a call to the pediatrician, though neither Waylon nor Ronan had one.

“Making people aware of this, both physicians and parents, is so important to us,” said Ms. Hood, who added that she and her husband are “hanging in there” as best they can. She is pumping and donating breast milk, which makes her feel as though she is at least helping other families. And they have explained to their 3-year-old son that Waylon is not coming home.

“He tells us that his baby is up with his moon and his stars,” she said.

Parechovirus tends to circulate in the late summer and early fall, and typically peaks every other year, the C.D.C. says. But beyond that, there is not much specific information about national infection rates and whether they are increasing.

“It’s not one we commonly test for, or that we necessarily need to test for,” Dr. Patel said. “It’s not a virus we nationally track, like influenza.”

The C.D.C. alert said it has received reports of cases since May, but did not specify how many or in which states. It did note, however, that the cases have all been a subtype of parechovirus known as A3, which is most often linked to severe illness.

Experts said it is possible that we are in the midst of an unusual surge in more severe cases exacerbated by what Dr. Alex Greninger, an assistant professor of laboratory medicine and pathology at the University of Washington School of Medicine, called “the 2022 effect”: People weren’t exposed to common pathogens during Covid lockdowns, which may have affected their immune systems. Now, people are getting out more and more, he said, and passing germs back and forth more than they had been.

But it is just as possible that we are simply testing more for parechovirus in babies who show meningitis-like symptoms, which could be leading to a seeming uptick in diagnoses. In recent years, many hospitals began using a test that checks spinal fluid for a range of pathogens that are known to cause meningitis and encephalitis — including parechovirus.

“Our ‘eyes’ have gotten better, therefore we are seeing more,” Dr. Alexander said.

The purpose of the C.D.C. alert is not to alarm parents, experts say. It is to help ensure that pediatricians and other health care providers are aware parechovirus is circulating, so they can consider it as a possible diagnosis in certain sick children.

After Ronan died, Ms. DeLancy set up a website where she hopes to spread awareness about his illness and raise money to fund research — in ways that are not entirely clear to her yet in her acute grief.

“I want my son to have made an impact in some way,” she said. “If he can potentially help other people, it can maybe give me some peace. I can’t save him, but he can help save someone else.”


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