Researchers found that children born prematurely are twice as likely to be hospitalized for flu-related complications than those without underlying medical conditions.
The research team, including Dr. Kay Wang of the University of Oxford in the UK, says their findings indicate that children born prematurely should be prioritized for receiving seasonal flu vaccinations.
According to the researchers, children with underlying medical disorders who develop flu are at much greater risk of flu-related complications than otherwise healthy children.
"Around 20% of children who present with influenza or influenza-like illness have at least one medical disorder," they add, "and the presence of comorbidities increases the rates of influenza-related hospital admissions almost six times in children aged 5 to 14 years. After being admitted to hospital, such at-risk patients are also at higher risk of further complications."
The World Health Organization (WHO) and the UK Department of Health recommend that all populations deemed to be at high risk of flu-related complications should be vaccinated against flu.
Although the US Advisory Committee on Immunization Practices recommend that all individuals aged 6 months and over should receive flu vaccinations, the guidelines state that antiviral medications should be targeted toward certain populations at high risk of flu-related complications.
But Dr. Wang and colleagues say the "guidelines are based on consensus opinion rather than evidence, and do not specify risk factors in children."
As such, the team set out to identify which children are at highest risk of developing complications from flu.
Preterm children 'twice as likely to be hospitalized for flu-related complications'
To reach their findings, the team analyzed 27 studies involving 14,086 children who visited a health care professional as a result of flu or flu-like illness. Of these children, 3,086 had underlying medical conditions.
From assessing seven studies involving 3,142 children, the team found that children born prematurely - before 37 weeks gestation - were twice as likely to be hospitalized for flu-related complications than children without underlying medical conditions.
Commenting on this finding, Dr. Wang says:
"Considering that around 10% (12.9 million) of the world's babies are born prematurely - with preterm delivery rates of around 6% in Europe, 11% in North America, and 12% in Africa - it's a significant public health issue and has major implications for policy makers."
The researchers also found that children with more than one underlying medical condition were at even greater risk of flu-related complications. While children with one medical condition were 48% more likely to be admitted to the hospital for flu-related complications than healthy children, those with multiple medical conditions were 78% more likely to be hospitalized.
Supporting current guidelines, the team also found that children with neurological disorders, sickle cell disease, immunosuppression, diabetes and those aged under 2 years were at greater risk of flu-related complications.
Dr. Wang says these findings indicate that policy makers need to be aware of which groups of children should be targeted with flu interventions - such as vaccinations and antiviral medications - particularly during flu outbreaks.
"To guide appropriate targeting of interventions to prevent influenza-related complications in children, our findings should be used to update definitions of patients regarded as at risk of such complications and to specifically define at-risk groups in children," the researchers add.
Interventions to prevent flu-related complications among children
In an editorial linked to the study, Harish Nair, from the University of Edinburgh in the UK, and Marc-Alain Widdowson, from the Centers for Disease Control and Prevention (CDC), say that there are many ways in which strategies to prevent flu-related complications in children can be improved worldwide.
"Examples include the introduction, or increasing the uptake of, influenza and pneumococcal vaccination globally, immunization of mothers against influenza to protect very young infants, and exploration of other vaccine types, such as adjuvanted vaccines that may be more immunogenic and cross-protective against non-matched strains," they say, adding:
"Implementation of these options should not wait for the next influenza pandemic, but be explored now to prevent the disproportionate burden of seasonal influenza on susceptible children every year."
Medical News Today recently reported on a study published in The Lancet Infectious Diseases claiming that the seasonal flu vaccine is effective in protecting over-60s during flu outbreaks.