New SARS data suggest infected pregnant women may be prone to premature childbirth but their babies may face a low risk of developing the disease.
A second study bolsters evidence that children with SARS are less severely affected than teens and adults.
The studies are too small to be conclusive, but they provide fresh insight into how the newly recognized virus affects children. They appear in the October issue of Pediatrics, published Monday.
SARS, a contagious and sometimes deadly virus, can cause symptoms similar to flu or pneumonia. It surfaced late last year in China and has infected more than 8,000 people worldwide, most of them adults in Asia. There have been 774 deaths.
Dr. Jairam Lingappa, a virus specialist at the federal Centers for Disease Control and Prevention, said it’s unclear why children would be less severely affected, but it might be because they are exposed to many other respiratory viruses, which could make their immune systems more resilient.
It’s also possible that many pediatric cases were missed because their symptoms were mild, said Dr. Yvonne Maldonado, an infectious disease specialist at Stanford University’s Lucile Packard Children’s Hospital who was not involved in the research.
Maldonado said the new studies provide important information, “especially right before respiratory virus season.” But she said it’s unknown whether children might be harder hit in any future SARS outbreaks.
It’s also unknown whether mild symptoms mean children aren’t very contagious, said Dr. Stanley Read of the Hospital for Sick Children in Toronto, an especially hard-hit city.
Read and colleagues investigated symptoms in 25 children treated at the hospital for suspected or probable SARS between March and June. They were age 2 on average. SARS eventually was ruled out in 10 of them.
All had fevers, but respiratory symptoms and coughs weren’t always present in the probable SARS cases. Only a teenage SARS patient developed respiratory distress and required oxygen treatment.
The findings suggest that the World Health Organization’s SARS definition “may not be sufficiently sensitive for young children,” the researchers said. The definition requires a fever above 38 degrees Celsius or 100.4 Fahrenheit and contact with SARS patients or travel to a SARS region.
The Toronto researchers said doctors should suspect SARS in children without respiratory symptoms if they have a fever and also had SARS contacts.
The study about SARS and childbirth involved five babies born to SARS mothers in Hong Kong. Three were born several weeks’ prematurely, likely because of their mothers’ illness. Two of the mothers died of SARS but none of the babies became infected.
The findings don’t exclude the possibility of mother-to-child transmission at childbirth but suggest the risk is low, said lead author Dr. Tai Fai Fok of Prince of Wales Hospital in Hong Kong.
Another study appearing in the issue describes the case of what is believed to be the youngest infected patient worldwide — a Hong Kong baby born about two months prematurely who contracted the sometimes deadly virus about two months after birth.
The study says the baby, who recovered, likely contracted the disease from SARS-infected children at the hospital where he was born or after being sent home. His mother was not infected.