Children develop the immune response to COVID without the virus appearing

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Ms. Sawenko’s family had been exposed to more than 50 close contacts, mostly through school and work, in the week before she and Mr. Maguire tested positive, but none of the people they came in contact with ended up testing positive.

“It was scary,” Ms. Sawenko said. “My biggest concern was for other people I had been around with. It wasn’t like your everyday sickness that you can turn to Dr. Google and say ‘what should I do? “There were literally no answers back then.”

In a twist that baffled doctors, all three children – aged nine, seven, and six – tested negative for the virus, despite both parents testing positive and their repeated exposure to the disease through shared services and hugging and kissing. parents every day.

The doctors were so perplexed that they tested each child four times to be sure. Each test returned a negative result.

A team of 30 researchers led by the Murdoch Children’s Research Institute closely examined the family’s immune system for a month. Samples including blood, saliva, nasal and throat swabs, feces, and urine were taken from the family every two to three days.

Pediatrician Shidan Tosif, who co-led the study published in Nature Communications This week’s newspaper said what was most surprising was that after extensive testing, all three babies found they had salivary antibodies to the virus.

This indicated that their immune systems had successfully shut down and fought the virus without them being “infected” and suggests that they had somehow activated an immune response.

The findings are potentially significant because questions remain as to why COVID-19 affects children and adults in different ways, with most children testing positive asymptomatic or showing only mild symptoms.

“This study is kind of our first step to really look into children’s immune systems and to see which components might respond to the virus,” said Dr. Tosif.

“The fact that these children were able to stop the virus and not even show a positive test result suggests that they have a certain level of their immune system that is able to respond and effectively deal with the virus, without ever becoming much. sick people”.

Despite the negative virus test, nine-year-old Bodhi still developed a mild cough, sore throat and abdominal pain, while 7-year-old Lenny also had a mild cough and runny nose. Six-year-old Marley, who shared a bed with her parents while they were contagious, had no symptoms.

“The youngest child, who showed no symptoms, had the strongest antibody response,” said fellow researcher Dr Melanie Neeland, who led the laboratory aspect of the study. He said his team performed a careful analysis of the children’s immune cells and types of antibodies.

Dr Tosif said that while the results looked promising, “they raised more questions than answers.”

Researchers are now looking at more children across Australia who have been family contacts of positive cases.

“What we want to know is, is this happening more broadly?” Dr. Tosif said. “It would be really amazing if there were so many other children who had an immune response and turned off the virus and we don’t even know.”

Emerging global research suggests that younger children have stronger immune systems, meaning their bodies can fight the virus faster than adults.

Other theories claim that adults are exposed to the coronavirus multiple times in their lives, with some experts speculating that their immune systems go into overdrive. Another hypothesis is that children are infected with lower doses of the virus to begin with, and therefore cannot replicate in children as well as it can in adults.

“We are now looking at how and why children respond in different ways when infected than adults and older people, because children are usually recognized as a vulnerable population for many viruses,” said Dr. Tosif.

“We also want to know how children of each age group respond to the virus and why there can be differences between the age groups.”

Ms Sawenko, 39, said the family happily endured months of whipping and prodding to help doctors better understand the virus.

“We were extremely anxious to be able to make a minimal contribution with our DNA and help scientists solve part of the mystery of the virus,” he said.

“We were just the guinea pigs, while they are the geniuses.”