Severe cases of strep A may be climbing in parts of the world outside of the UK, where the surge was first reported. Several children’s hospitals in the U.S. have documented an increase, while doctors in Montreal, Canada recently reported a possible rise in the area as well, along with two child deaths. These surges are likely linked to a lack of a population immunity to the bacteria, as well as a concurrent rise in respiratory viral infections such as influenza, health officials have said.
Strep A infection can cause a variety of conditions, such as scarlet fever and strep throat. Most of the time, these illnesses are mild and self-limiting or can be treated easily with antibiotics. Severe strep A, also known as invasive group A streptococcus (iGAS) disease, is much rarer but can be life-threatening, leading to complications like septic shock and organ failure.
The strep A surge in the UK is believed to have begun in September. There have been nearly 30,000 reported cases of scarlet fever in the country this fall and winter, along with at least 24 suspected pediatric deaths, according to the latest update this week from the UK Health Security Agency. Though the UK has experienced large peaks of strep A and iGAS in recent years prior to the pandemic, these current cases are occurring outside of the typical season early in the spring.
Other countries and health agencies throughout the world have since been on the lookout for similar surges. In the U.S., the Centres for Disease Control and Prevention has been investigating a possible rise in cases, while local health departments and hospitals in Minnesota, Missouri, Arizona, Texas, and Colorado have reported higher-than-usual numbers of strep A cases. Last week, Montreal health officials released a public alert following the local deaths of two children from the infection.
Officials in the UK have so far ruled out the possibility that more virulent strains of strep A are to blame for the increased severity of these outbreaks, though they are studying the genetics of strains collected from patients to make sure. The reduced exposure to strep A infections among the population in recent years is a major factor in these unusual waves of illness, UK officials have said. These cases are also happening against the background of other infections resurging lately, such as influenza and respiratory syncytial virus (RSV), as well as the ongoing covid-19 pandemic. And since co-infections with germs like flu can raise the risk of severe illness from strep, that may be playing an important role as well.
Severe strep A does still appear to be a very rare complication during these peaks. And the potential risk of co-infections may be decreasing in places like the U.S. Flu activity remains high in much of the country, according to the CDC’s latest update, but may be declining in some areas. RSV activity is on the downswing as well. Reported cases of covid-19 have been increasing in recent weeks, but deaths and hospitalizations are much lower than they were during the previous two winters. At the same time, it’s likely to take weeks or months before these infections completely level off, so people should remain cautious.
Suspected cases of scarlet fever can be treated with antibiotics before they become more severe, for instance. Masking and avoiding contact with others while sick with respiratory symptoms will help tamp down the spread of many infections this winter. And the flu shot and covid-19 boosters will significantly reduce the risk of severe illness if you’re unlucky enough to catch either.