Severe group A strep infections in kids could be spiking due to vaccine-preventable viruses, doctors say

Open this photo in gallery:

Four B.C. children under age 10 have died since mid-December as a result of a severe bacterial infection they contracted alongside respiratory viruses, underscoring the seriousness of the recent increase in cases of the rare disease in pediatric patients across the country.

This month, a report from Public Health Ontario indicated a significant rise in invasive group A streptococcal (iGAS) infections, noting that from October to the end of December, there were 540 cases in the province, including six deaths in people under 18.

Medical experts say they believe the growing number could be the result of a spike in influenza and other respiratory illnesses that have been affecting children, which points the need to improve vaccination rates and take other protective steps.

On Thursday, B.C. health officials said that there were 60 cases of iGAS in people under age 20 in the province last year, triple the amount reported the previous year. Of the four children who died recently, two had been recently diagnosed with the flu, while two had human metapneumovirus, another respiratory virus.

Viral illness weakens the body’s defences, making it easier for harmful bacteria to enter, said Caroline Quach-Thanh, a pediatric infectious diseases specialist and medical microbiologist at CHU Sainte-Justine in Montreal.

“We’re seeing much more viral infections that open the door to super infections with bacteria,” said Dr. Quach-Thanh, who is also a professor at the University of Montreal.

Group A streptococcus bacteria typically cause mild illnesses, such as skin infections or strep throat. But in rare cases, the bacteria becomes invasive, meaning it enters the bloodstream or deep tissue, where it can cause serious harm. The majority of those with iGAS require hospital admission, and between 5 and 15 per cent of individuals die as a result. Severe strep infections can cause a range of illness, including meningitis, pneumonia, toxic shock syndrome and flesh-eating disease.

Upton Allen, head of the division of infectious diseases at Toronto’s Hospital for Sick Children, said he and his colleagues are discussing the possibility that increased spread of the flu, respiratory syncytial virus and other infections may be responsible for the changes.

“It’s possible that the kids, because of the lockdown that occurred during COVID, might not have had an opportunity to be exposed to a variety of viruses and therefore, might not have the degree of the leftover protection that they would originally have gotten when they got infected one season over the next,” Dr. Allen said.

While older individuals are one of the higher risk groups for contracting iGAS, along with people who have chronic diseases or other conditions that compromise their immune response, medical experts say the rate of infections appears to be rising fastest among children.

Joanne Langley, division head of infectious diseases and professor in the department of pediatrics at Dalhousie University in Halifax, said she also believes it’s possible that recent increases in respiratory virus spread could be leading to more invasive strep infections in kids.

“We know upper respiratory infections put you at risk,” Dr. Langley said.

Dr. Allen said there are several symptoms that could indicate iGAS, such as fever lasting longer than five days; fever and a rash that feels like sandpaper; fever in infants under three months; lethargy or difficulty waking a child; or any breathing difficulties. Any of these symptoms should trigger a trip to the emergency department, he said.

Dr. Langley and other experts note that chicken pox in particular comes with a heightened risk of iGAS, as the multitude of open sores on an individual’s body all represent possible portals of entry for the harmful bacteria.

Dr. Langley said she wants families to understand the connection between viral illness and severe strep infections so that they can take steps to protect themselves and their children, such as by getting vaccinated.

“It highlights how important those two vaccination programs are, influenza and chicken pox. We know invasive strep infections are consequences of those viral infections and vaccination will prevent that.”

Vaccination rates among children fell during the pandemic, as routine immunization programs were disrupted and disinformation about vaccines spread. Canada does not have a national vaccine registry, and many provinces haven’t updated their publicly-available data on vaccine coverage.

But in Ontario, the immunization rate for measles among seven-year-olds fell to 52.5 per cent in the 2021-22 school year, down from 85 per cent in the 2019-20 school year. For the chicken pox vaccine, coverage among seven-year-olds fell to 49 per cent in the 2021-22 year, down from 82 per cent in 2019-20.

While Canada hasn’t experienced any significant outbreaks of measles or chicken pox, Dr. Quach-Thanh said viruses such as the flu, which are spreading in large numbers, are likely playing a role.

“The only thing you can do is keep up-to-date with basic childhood vaccinations,” she said. “Aside from that, there is not much you can do to prevent invasive group A strep infections. I think that’s what’s scary for a lot of parents.”