Ethnic minority children and children with severe chronic diseases died at a disproportionate rate during the H1N1 pandemic of 2009 and 2010, a U.K. government study has found, and the influenza pandemic proved deadlier to England’s children in general than did leukemia in any given year.
In their analysis of all 70 laboratory-confirmed H1N1 deaths in England for people younger than 18 years, published online Oct. 27 in the Lancet, Dr. Liam J. Donaldson of the U.K. National Patient Safety Agency and Dr. Nabihah Sachedina of the U.K. Department of Health showed overall pediatric mortality from pandemic influenza to have been 6 per million population. This rate is three times as high as England’s normal estimated pediatric death rate up to age 14 years for seasonal influenza, and slightly higher than the Netherlands death rate of 5 per million (in children under age 14) during the pandemic period (Lancet 2010 Oct. 27 [doi:10.1016/S0140-6736(10)61195-6]).
More prone to fatal pandemic H1N1 infection in England, the investigators found, were children born to Bangladeshi and Pakistani families – 47 and 36 per million, respectively, compared with 4 per million for white children. The authors said the finding “might be attributable to clustering of pandemic influenza A(H1N1) cases in areas of England with high ethnic minority populations,” although areas with lower ethnic minority populations were also affected, they noted. The authors allowed that more preexisting disorders might be present among ethnic minority children, but said there were few data to support the claim; among the 70 cases studied, preexisting health status did not differ among ethnic groups, they said.
Of the 70 fatal pediatric H1N1 cases recorded between June 26, 2009, and March 22, 2010, children with severe preexisting disease accounted for 45, or 64%, the investigators found; 15, or 21%, were healthy, and the rest had mild or moderate existing disease. Deaths occurred evenly between boys and girls (31 and 39, respectively), with the median age at death 7 years. Children under age 1 year also saw a higher rate than children as a whole (14 per 1 million population).
“Chronic neurological, gastrointestinal, or respiratory disease were all present in more than half of all deaths,” the authors wrote. Of the 35 children with neurological disorders who died, 19 had spastic quadriplegic cerebral palsy. Half of the school-age children who died had attended schools for children with special needs; nearly a quarter had been born prematurely. A prior diagnosis of asthma was present in 5 deaths, complex congenital cardiac disease was reported in 8, severe gastroesophageal reflux was reported in 11, and regular gastrostomy or nasogastric feeding took place in 41.
Some 27% of the deaths occurred before the child could be admitted to a hospital, the researchers said, and children in this group were likelier to have been healthy or to have only mild preexisting disorders than were those who died after admission.
In more than three-quarters of the deaths, primarily respiratory symptoms were reported at presentation; in two cases, mainly gastrointestinal symptoms were reported. Among hospital deaths, nearly a quarter of the children presented in cardiorespiratory arrest; only one presented with nonspecific symptoms, the investigators said.
Importantly, only two of the children who died had been vaccinated, and they had received vaccine too late – within 2 days before becoming sick – for it to be effective, they said.
The investigators concluded that children with the identified risk factors for death from influenza should be prioritized for vaccination.
The study was funded by the U.K. Department of Health. Dr. Donaldson was the chief medical officer for England from 1998 to May 2010. In this role he advised the government on the management of the pandemic. Dr. Sachedina supported him in this task from 2009 to 2010. They declared that they had no additional conflicts of interest.
In a comment accompanying the article, Dr. Robert A. Fowler and Dr. Philippe Jouvet of Sunnybrook Hospital, University of Toronto, said the fact that previously healthy children accounted for more than one-fifth of the deaths was a serious concern as well (Lancet 2010 Oct. 27 [doi:10.1016/S0140-6736(10)61385-2]).
“Although this finding is not more important than the identification of underlying medical risk factors, it represents a persistent message of the H1N1 pandemic – that children and young adults who were not expected to become severely ill because of influenza did so, and in greater numbers than with seasonal influenza,” they wrote.
Dr. Fowler and Dr. Jouvet declared they had no conflicts of interest.
Copyright (c) 2010 Elsevier Global Medical News. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
一项研究表明，在2009和2010年H1N1流感大流行期间，少数民族儿童和患有重症慢性疾病的儿童死亡率异常增高，对英国儿童而言，大流行性流感的致死性在任意年份都强于白血病。
研究共纳入70例实验室确诊的H1N1死亡病例(均为英国籍，年龄＜18岁)，患儿的发病时间介于2009年6月26日~2010年3月22日之间，感染H1N1流感前就存在严重疾病的儿童占总人数的45%(或64%)，健康儿童占15%(或21%)，余下儿童存在轻度至中度疾病。死亡病例中男孩和女孩的比例十分接近(分别为31和39例)，死亡中位年龄为7岁。1岁以下儿童死亡率(14/1000,000)较整个儿童群体高。
英国儿童大流行性流感死亡率为6/1000,000 (Lancet 2010 Oct. 27 [doi:10.1016/S0140-6736(10)61195-6])。其中，出生于孟加拉国和巴基斯坦家庭的儿童更易因为感染大流行性H1N1流感病毒而死亡，其死亡率分别为47/1000,000和36/1000,000，相比之下白人儿童死亡率仅为4/1000,000。大流行性甲型H1N1流感病例在英国某些少数民族聚居的区域发病率极高，就目前已研究的70例病例资料看来，不同民族儿童原始健康状况并无差异。
超过半数的死亡病例生前都存在神经、消化或呼吸系统疾病，罹患神经系统疾病者总计35例，其中19例存在四肢麻痹性脑瘫。在死亡病例中，有超过半数学龄儿童曾至特殊需求儿童学校就读，有近1/4是早产儿。5例儿童生前曾被确诊患有哮喘，8例存在复杂先天性心脏病，11例存在严重胃食管反流症状，还有41例患儿生前曾接受常规胃造瘘术或通过鼻饲管进食。有27%患儿在被医院收治前便已病发死亡。与住院后才死亡的患儿相比，这部分儿童中原本健康状况良好或仅存在轻度疾病的比例更高。在住院后死亡的患儿中，有超出3/4的患儿在入院前就存在原发性呼吸道疾病，还有2例患儿主要存在胃肠道疾病。有近1/4患儿因心跳呼吸骤停死亡，仅有1例死亡时无特定症状。仅有2例死亡患儿在生前曾接种疫苗，但接种时间在发病前2天，短于疫苗生效所需的最短时间。
在死亡病例中，原本健康的儿童所占比例超过1/5，这一问题值得密切关注，因为原先认为这些患儿不会因为感染流感而发生重度疾病，但事实打破了这一臆测，大流行性流感导致患儿出现重症的能力远超季节性流感(Lancet 2010 Oct. 27 [doi:10.1016/S0140-6736(10)61385-2])。对确认存在某些危险因素的儿童应该优先接种疫苗。
本研究由英国卫生部资助。研究者表示无其他利益冲突。
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