Antibiotics for sore throats have little protection against serious streptococcal infections in the population, according to research from the University of Gothenburg. Instead, healthcare providers need to quickly recognize warning signs of serious infections.
Group A Streptococcus (GAS) is a common bacteria that can cause invasive GAS infections (iGAS) when it enters the blood or lungs. This condition can be life-threatening and is relatively rare, but the incidence has increased in several countries in recent years.
A simple sore throat can sometimes develop into iGAS or be transmitted to other people in the community, so early antibiotic treatment is often discussed as part of preventive measures.
However, the researchers behind the study, published in the International Journal of Infectious Diseases, showed that prescribing antibiotics for acute uncomplicated sore throats to prevent iGAS has very limited effectiveness at a population level.
“The intention to prevent iGAS infections should no longer be used as an argument for treating common throat infections with antibiotics; that strategy is greatly overrated,” says the study’s lead author Ronny Gunnarsson, a family physician and professor emeritus at the University of Gothenburg.
Minimal preventive effect
By combining scientific evidence with epidemiological data for the entire Swedish population in 2024, the researchers calculated how different strategies would affect the incidence of iGAS.
The results show that even in the extreme scenario that all patients seeking treatment for a sore throat are tested and treated if they carry the bacteria, up to 6.7 percent of iGAS cases could be prevented in children and 2.8 percent in adults.
If instead we follow the current Swedish guidelines, in which testing is only done if a patient meets three to four specific symptoms according to the center’s criteria, the protection effect would be up to 1.6 percent in children and 1.2 percent in adults.
The proportion of iGAS cases that can actually be prevented with antibiotics is much smaller than thought. Our calculations show that to prevent just one case of iGAS, we would have to collect throat swabs from 45,000 to 110,000 patients and write up to 110,000 antibiotic prescriptions. ”
Ronnie Gunnarsson, University of Gothenburg
become contagious before visiting a medical institution
Researchers point to several reasons why antibiotics may be ineffective against iGAS at the population level. Most people do not call a medical center if they experience a sore throat. Infected people usually receive treatment after the third day of illness, when they are already past their most contagious period.
Additionally, 15 to 25 percent of iGAS patients are infected asymptomatic carriers, people who feel perfectly healthy and therefore should not be given antibiotics. The study concludes that lower standards for sore throat testing and treatment could have major negative consequences for primary care.
“Broadening the standards for sampling and antibiotic treatment would place a huge burden on primary care and exclude other patient groups, not to mention the risk of side effects from antibiotics,” said Ronnie Gunnarson. He continued, “Instead of prescribing antibiotics for a simple sore throat, medical care should focus on quickly recognizing early warning signs of serious infections and, in the long term, wait for the development of safe and effective streptococcal vaccines.”
