With the tragic news of the deaths of 15 children in England from strep A infection, researchers are under pressure to explain the increase in cases. A commentary in Nature in December 2022 suggests that the “off-season outbreak” has “jumbled expectations”. A common theory is that due to the sheltering effect of COVID-19 lockdowns, children have been unable to develop immunity against the bacteria.  

An unlikely surge 

Infections are frequently observed increasing during springtime, with a “tail off” by the summer. Thus, the rise in infections and deaths since September is surprising to some. Professor Shiranee Sriskandan of Imperial College London believes that “we’ve never seen a peak like this at this time of year, at least for decades”.  

Between September and November 2022 there were 4,622 notifications of scarlet fever in England, a dramatic increase from the previous 5-year average of 1,294. However, for Professor Sriskandan, “scarlet fever is the tip of the strep-throat iceberg” as a “visible marker of what’s going on in the community”.  

This surge is not confined to the UK. Professor Nina van Sorge of the Amsterdam University Medical Centre suggests that “cases are still remarkably high in the Netherlands”. There, officials are urging health workers to treat suspected cases with antibiotics immediately.  

Why now? 

Although the suggestion that reduced exposure during lockdowns is driving this increase, Dr Claire Turner of the University of Sheffield thinks it is too early to tell. Dr Turner specialises in the mechanisms behind peaks in group A strep. Through whole genome sequencing, epidemiology, clinical analysis, and phenotype work, she investigates the causes of successful and prolific strains. Using 3D cultures of lab-grown tonsil cells, she hopes to evaluate this year’s samples.  

As we noted in our previous article on GAS, the need for a safe and effective vaccine is evident. For updates on progress towards this at the World Vaccine Congress in Washington 2023, get your tickets today.