US Swine Flu Death Toll Includes 36 Children, Report

Federal officials reported this week that at least 36 children have died in the US as result of the 2009 pandemic swine flu virus A(H1N1), two thirds of whom had one or more high risk medical conditions. Over 90 per cent of the children who had medical conditions had neurodevelopmental disorders such as developmental delay or cerebral palsy and health-care professionals are urged to be aware of the potential for more severe illness, including death, among these children.

The report also shows that most of the children with neurodevelopmental conditions who died had more than one neurodevelopmental diagnosis and/or pulmonary conditions.

In addition, doctors should be aware of the higher risk of severe bacterial coinfections in children who have flu and treat accordingly. Over 40 per cent of the reported deaths for which lab results were reported, showed the children also had bacterial coinfections.

The figures appear in this week's MMWR report from the US Centers for Disease Control and Prevention, which details results of surveillance for pediatric deaths linked to the 2009 pandemic swine flu from April to August.

As of 8th August, the CDC said it had received reports of 477 deaths linked to pandemic swine flu, including 36 deaths among children aged under 18 years of age. The youngest patient was 2 months old, and the oldest was 17. The figures also show that 7 of the children were under 5 years old (5 were under 2 years old).

The deaths of the 36 children were reported from 15 state and local authorities. Half were male, 42 per cent were non-Hispanic white and 33 per cent were Hispanic. Six deaths occurred in May, 25 in June, and 5 in July.

24 of the 36 children who died of swine flu had at least one high risk medical condition, including three children under 5. Of the children with high risk medical conditions, the vast majority (22 children, 92 per cent) had neurodevelopmental conditions (such as developmental delay or cerebral palsy).

13 of the 22 children with neurodevelopmental conditions had more than one such diagnosis and 9 of them had neurodevelopmental and chronic pulmonary conditions.

8 of the 36 children who died of swine flu were aged 5 years and over and had no reported high risk conditions. Although two of these children were reported as obese, no data was given on their height and weight.

The children were ill for a median of 6 days (ranging from 1 to 28 days) before death occurred. Early diagnosis of flu means children at greater risk or who are severely ill have a greater chance of being treated effectively with antivirals, yet among the 19 children reported to have received antiviral treatment, only four of them started treatment within 2 days of falling ill with swine flu.

An editorial note pointed out that 28 (nearly 80 per cent) of the 36 children who died of swine flu were in one of two groups already known to be at higher risk from seasonal flu: they were either under 5 years old or they had a pre-existing medical condition. However, the percentage of children with high risk medical conditions who died of swine flu is higher than the percentage reported in recent flu seasons and this needs to be monitored to see if this and other differences between seasonal flu and swine flu are important.

The report also highlights the prominence of laboratory-confirmed bacterial coinfections, which were found in 10 (43 per cent) of the 23 children who had culture or pathology results reported. 6 children aged 5 and over with no high risk medical condition had an invasive bacterial coinfection, suggesting that swine flu combined with bacterial infection can result is severe illness in otherwise healthy children.

When reading the report people should bear in mind that the figures may not be accurate for a number of reasons. For example, cases of flu deaths among children may be under-reported, for instance because there is a low level of flu testing among children. Also it is difficult to compare swine flu cases with seasonal flu cases because of the difference in availability of reliable diagnostic tools.

The best way to stop people getting swine flu and its complications is to vaccinate them, said the CDC, who recommend that everyone between the age of 6 months and 24 years should be vaccinated against the 2009 H1N1 swine flu virus, for which vaccine doses should be available in mid-October. People who live with or care for babies under 6 months old should also be vaccinated, regardless of their age.

CDC Morbidity and Mortality Weekly Report, September 4, 2009 / 58(34); 941-947