Some Kids Are More Likely to Get Strep Throat Over and Over Again—Here's Why

Some children are more likely to get strep throat repeatedly because a combination of their genetics and how the bug manipulates their immune system. That's according to researchers, who hope a vaccine for the nasty condition is on the horizon.

As repeated sufferers will know all too well, strep throat can cause a fever, painful swollen tonsils that can become red and streaked with puss, and puffed-up lymph nodes in the neck. Unlike other sore throats, it does not cause a cough. While most sore throats are caused by viruses, strep throat is caused by the A Streptococcus bacteria.

As many as 600 million cases of strep throat are diagnosed each year, the authors said. Repeated attacks can cause children to miss school and use antibiotics over and over, which can make the drugs less effective. In some cases, the bouts are so severe that children have to have their tonsils removed. While such procedures have a high success rate, all surgeries carry risks, the authors said. It's a mystery, they wrote, why some children develop immunity to strep throat and others don't.

Dr. Shane Crotty, study author and Professor at the La Jolla Institute for Immunology (LJI) told Newsweek: "Recurrent tonsillitis appears to involve genetic susceptibility related to certain immune system functions, and the strep bacteria directly target the immune system cells in a way that prevents proper protective immunity in some kids."

Crotty explained to Newsweek that tonsils are an important part of the immune system, because they trap bacteria and viruses before then can infect the body. However, they can paradoxically also provide the perfect conditions for bugs like Group A Streptococcus to thrive.

The researchers studied the tonsils of 65 children aged 5 to 18 years old from the San Diego area who had their tonsils removed. Some 26 had experienced recurrent strep throat (12 times on average), while 39 needed the surgery for unrelated conditions like sleep apnea.

The researchers found that the bacteria give off virulence factors—or molecules which help them to survive in a host—which change the immune response of tonsils, Crotty told Newsweek. This can turn "helper t-cells," which create antibodies to prevent infection, into "killer t-cells," potentially decimating the antibody response and the ability of a child's immune system to neutralize strep.

This could explain their finding that some children with recurrent strep throat had smaller germinal centers, the parts of lymph nodes that can trigger an immune response, he explained.

Children who suffered from strep throat again and again were also found to likely have a family history of the tonsil problem. Tests on their genes revealed two genetic variants that determine how the immune system processes viruses and bacteria.

But Crotty acknowledged: "Limitations of the study included geography, as tonsils were only collected from children within the San Diego area. However, this allowed for us to control for the same circulating strep strains during the years of the study."

He encouraged other researchers to replicate the results and provide further insight into the unpleasant disease.

Unfortunately, the study doesn't provide much short-term help for those worried about their child getting strep throat, or those coping with what can feel like unrelently assaults by the bug.

"If you have symptoms of tonsillitis and or recurrent strep throat, see your pediatrician for a throat culture and or rapid strep test," he said.

"But, it [the study] may lead to diagnostic tests in the future, or facilitate vaccine development."

The study was published in the journal Science Translational Medicine.