Scientists identify how children develop immunity to bacterial infection, paving way for vaccine

London | Scientists have discovered how young children naturally develop immunity to bacterial infection Strep A, a breakthrough that could speed up vaccine development and save up to half a million lives each year, a new study has said.

Strep A, or Group A Streptococcus, is a common bacterium that can cause mild conditions such as sore throat and skin infections, but in severe cases leads to life-threatening illnesses.

Thousands of people in low and middle-income countries die each year after contracting the infection, however, deaths from Strep A are relatively uncommon in more affluent nations by comparison. A deadly Strep A outbreak in the UK and Europe in late 2022 resulted in hundreds of deaths, including of many children.

Working in partnership with the Medical Research Council (MRC) Unit The Gambia at London School of Hygiene and Tropical Medicine, the University of Sheffield research team tracked how children in The Gambia develop natural immunity to Strep A.

They were able to identify the specific antibodies that are linked to protection from the potentially fatal infection, according to the study published in Nature Medicine, a monthly medical journal.

The researchers looked at how antibodies - our natural defence against infection - develop in people in The Gambia from birth and throughout their lives. It found that infants are born with some maternal protection against Strep A, but that quickly fades away. Young children rapidly develop antibody responses to various parts of the bacteria after exposure to Strep A. “Identifying this key window for developing immunity is a critical discovery for future vaccine strategies,” the study said.

Lead author Dr Alex Keeley, a Wellcome Clinical PhD Fellow in Global Health at the MRC Unit the Gambia and the University of Sheffield’s Florey Institute of Infection, said understanding this process removes a major obstacle to vaccine development. “For the first time in humans, we have observed how antibodies formed after vaccination could work to prevent infections,” he said.

Gambian scientist Fatouamta Camara, who was part of the research, said Strep A has a “devastating burden” on communities, both in health and socio-economic impact. “A vaccine offers hope to break this cycle and allow children to thrive,” she said.

The study was part of a collaboration between Sheffield’s Florey Institute of Infection and the GSK Vaccine Institute for Global Health.

Professor Thushan de Silva, Co-Director of the Florey Institute of Infection in Sheffield and a Principal Investigator at the MRC Unit The Gambia, who supervised the research, said: “This study reflects the value of working across institutions to deliver high-quality, impactful research in global health.”