Stroke in childhood is a rare but serious medical event, and recent evidence suggests that everyday illnesses may increase the risk of stroke occurrence. Recent research published in Neurology The study shows that children who have had an infection are more likely to have a stroke soon afterwards, but recent vaccinations have shown no such association. These findings highlight the importance of infection prevention to protect vascular health in young people.
A stroke occurs when blood flow to the brain is cut off or when a blood vessel ruptures. Stroke in adults is often associated with conditions such as high blood pressure and high cholesterol, but children who experience stroke usually do not have these standard risk factors. Rather, childhood strokes tend to be caused by genetic disorders, heart defects, or blood clotting disorders.
Scientists are increasingly investigating the role of infectious diseases as potential triggers of these events. Previous small studies had pointed to a possible link between childhood stroke and common illnesses such as respiratory infections. However, comprehensive data tracking the entire population over several years is lacking.
Researchers wanted to establish exactly how common childhood strokes are in modern humans. They also sought to determine whether recent infections or recent vaccinations played a direct role in causing these medical emergencies. Some past reports hinted at potential risks after certain childhood vaccinations, but the scientific community needed to see if those findings held up in larger trials.
“While stroke is typically thought of as a disease of the elderly, it can actually occur at any age, including children. We decided to investigate stroke in childhood in this study to fill knowledge gaps in the epidemiology of the disease, including its incidence, contemporary trends, and associated risk factors,” explained study author Lachlan Dalli, a postdoctoral fellow in the School of Clinical Sciences at Monash University.
To conduct the study, scientists analyzed health records from the Australian state of Victoria from 2017 to 2023. They looked at data for all residents from 28 days old to under 18 years old. This geographical region includes a population of approximately 1.4 million children.
The researchers used a secure system that linked hospitalizations, emergency department visits, death registrations, and national immunization records. This linked system has made it possible to track serious medical events, recent illnesses, and vaccination histories for millions of young people over time.
Over a seven-year period, scientists identified 571 children who had experienced a stroke. About 60% of these events are ischemic strokes, which occur when a blood clot blocks blood flow to the brain. The remaining 40% are hemorrhagic strokes, which occur when weak blood vessels rupture and bleed into surrounding brain tissue.
To understand what caused these events, scientists set up a matched comparison. They paired each stroke patient with up to five healthy control patients of exactly the same age and gender. They ultimately matched 571 cases of childhood stroke with a total of 2,734 control patients. These control patients were hospitalized in the same year for reasons completely unrelated to stroke.
The researchers also found that the control group shared similar neighborhood wealth levels and pre-existing medical conditions. This matching process helps filter out background differences in health and lifestyle to isolate specific variables of interest.
The scientists then looked at whether the children had recorded an infection in the 60 days before hospitalization. They looked for symptoms such as respiratory illness, gastroenteritis, and more severe systemic infections. They also checked the National Immunization Registry for vaccines given 42 days ago, a period commonly used in vaccine safety studies.
Data shows that childhood strokes occur at a rate of approximately 5.8 per 100,000 children each year. The researchers noted that among the study population, boys and infants under 1 year of age had the highest stroke rates. Additionally, scientists found that the overall incidence of childhood stroke increased by 42% between 2017 and 2023.
Researchers suggest that this increase may be due to improvements in medical imaging and hospital coding practices over time. Focusing on specific types of events, the incidence of ischemic stroke was 3.7 per 100,000 children. However, the incidence of hemorrhagic stroke was slightly lower at 2.1 per 100,000 children.
Evidence also shows that two out of five children who have a stroke experience an infection in the two months leading up to the event. The most common illnesses reported were lower respiratory tract infections, upper respiratory tract infections, and a widespread systemic infection known as sepsis. Other frequently seen diseases include meningitis, a severe inflammation of the fluids and membranes surrounding the brain and spinal cord.
Upper respiratory viruses were particularly common among children who had experienced a stroke. These include coronavirus infections, respiratory syncytial virus, influenza virus, and pneumococcal infections. Gastroenteritis and urinary tract infections were also prevalent among stroke patients.
Scientists compared two matched groups and found that having a recent infection more than doubled the odds that a child would develop a stroke. This increased risk was strongest during the first 2 weeks after illness onset. The association between infection and stroke was slightly higher for ischemic stroke than for hemorrhagic stroke.
Specifically, recent infection increased the odds of ischemic stroke by more than threefold. Data suggest that ischemic stroke risk remains elevated for up to 6 months after infection. For hemorrhagic strokes, the increased risk tends to wear off after about two months.
“Our research shows that the risk of stroke in childhood is not only immediate, but is highest two weeks after infection and remains elevated for up to six months,” Dali told SciPost. “This suggests that doctors and parents may need to think beyond the recovery phase and be on the lookout for stroke warning signs beyond the acute infection phase.”
Scientists found no significant association between recent vaccinations and childhood stroke. Only about 4% of stroke patients had received the vaccine in the weeks before their medical emergency. This vaccination rate was statistically similar to that seen in healthy control groups.
This finding ensures the safety of standard childhood immunization programs. It also highlights that the infection itself poses a far greater risk to vascular health than the vaccines designed to prevent it.
Although the study provides strong evidence linking infections and stroke, scientists note several limitations. Reliance on hospital and government register data means mild infections treated at home are likely not counted. Because the data was anonymous, the scientists were unable to review individual medical records to confirm the exact diagnosis or severity of the stroke.
This type of administrative record keeping can lead to some errors in how certain diseases are classified. Scientists also point out that such observational studies cannot definitively prove that the infection directly caused the stroke. An abnormal immune system response or other unmeasured genetic factors may have contributed to the vascular problems.
Future studies should investigate the specific biological mechanisms that may cause vascular insufficiency after infection. Scientists also need to assess whether widespread vaccination programs have the potential to reduce the long-term incidence of childhood stroke. Preventing the very infections that often cause these emergencies may be a viable strategy to protect young patients.
The study, “Incidence of pediatric stroke and its association with recent infectious diseases: A population-based study using linked data,” was authored by Lachlan L. Dalli, Muideen T. Olaiya, Hannah J. Morgan, Monique F. Kilkenny, Michael C. Fahey, Mark T. Mackay, Dominique A. Cadilhac, Tzu-Yung Kuo, and Seana L. Gall. Hazel J. Clothier, Jacqueline A. Boyle, John Mallard, Danita Hennessy, Jim Buttery.
