Very low pandemic influenza A (H1N1) 2009 mortality associated with early neuraminidase inhibitor treatment in Japan: analysis of 1000 hospitalized children

Objective

There were many cases of pandemic influenza A (H1N1) 2009 (H1N1/09) in Japan during the 2009–2010 epidemic. They accounted for 16% of the total population (20.7 million/128 million), and 59% of the patients were children 15 years of age and under (12.2 million/20.7million). However, there were only 38 paediatric deaths. We analyzed the clinical manifestations and treatment of children hospitalized because of H1N1/09 infection in order to clarify the association between treatment with neuraminidase inhibitors and the low mortality rate.

Methods

A retrospective chart review was performed on a total of 1000 paediatric inpatients.

Results

The causes of the hospitalizations were respiratory complications in 651 cases (65.1%), neurological complications in 255 cases (25.5%) and other complications in 94 cases. Neuraminidase inhibitors, primarily oseltamivir, had been used to treat 984 (98.4%) of the 1000 patients, and in 88.9% of the patients, treatment with neuraminidase inhibitors was initiated within 48 h after the onset of illness. Only 12 (1.2%) of the 1000 patients underwent mechanical ventilation, and one patient died of H1N1/09 infection.

Conclusions

Although a high proportion of the patients in this study had severe respiratory complications, the case fatality rate was only 0.1%. The low mortality rate of children due to the H1N1/09 epidemic in Japan was probably attributable to the universal implementation of early treatment with neuraminidase inhibitors.     

北京市怀柔区人群甲型H1N1流感抗体的血清学研究

目的:研究北京市怀柔区普通人群中甲型H1N1流感病毒抗体的分布情况并阐明其特点。方法:自2010年1月开始,选取怀柔区共2323名调查对象进行回顾性问卷调查,并采集血清标本进行甲型H1N1流感病毒血凝抑制抗体(HI)水平的检测。结果:31.38%的调查对象体内HI抗体为阳性。接种疫苗者的血清学反应阳性率为40.45%,未接种疫苗但血清学反应阳性并出现呼吸道感染症状的可达26.57%。不同年龄组的HI抗体阳性率也不同(P<0.01)。多因素Logistic回归表明年龄、职业、是否集体生活、H1N1疫苗接种史和抗体滴度有关,性别对HI抗体阳性率则无明显的差异。结论:研究表明怀柔区普通居民体内都有一定的HI抗体滴度,从而可能对H1N1流感病毒起到一定的免疫功能;这同北京市早期的相关报道是相一致的。     

Influenza vaccine and healthcare workers

We undertook this study to review attitudes, beliefs and practices of healthcare workers (HCW) toward pandemic influenza A vaccine (H1N1) 2009 reported in the literature. Relevant papers published from 2009-2011 reporting attitudes, beliefs and practices of HCW towards pandemic influenza vaccine were identified. Variables such as age, gender, profession, work place area, and previous vaccination uptake were analyzed. In this study, 30 articles regarding attitudes and beliefs toward pandemic influenza vaccination, vaccine uptake and intention to accept vaccine were analyzed. Most studies were cross-sectional in design. Vaccination intention and uptake varies among different countries, 13.5-89.0% and 7.5-63.0%, respectively. Most common reasons for rejection were fear of adverse events, doubt regarding efficacy, not feeling as belonging to a high-risk group and believing that influenza is not a serious illness. Physicians show more favorable attitudes compared to nurses. The main predictor of vaccine uptake was having received previous influenza vaccination. Pandemic influenza uptake was low in most countries. The main reason among HCW for rejection was concern regarding side effects. It is necessary to establish educational programs to provided reliable information and raise awareness of HCW about?vaccine use so that they can act as vaccine promoters among the general population.     

中国五省(区)市疾病预防控制机构流感大流行应对能力现状研究

目的了解浙江、新疆、山东、贵州、武汉五省(区)市疾病预防控制机构的流感大流行应对能力现状,研究针对性干预措施。方法对五省(区)市的59家疾病预防控制中心进行问卷调查,数据进行描述流行病学分析。结果调查的各级疾控中心均成立了应急处置组织体系,制定了流感大流行应急预案并开展演练和培训;75.00%的省级、55.56%的市级和51.35%的县级疾控中心认为储备的消毒药品不能满足重大突发公共卫生事件的处置需求;省、市级疾控中心均具备流感病毒检测能力,但县级疾控中心仅浙江省有69.57%可以开展检测。结论五省(区)市疾控机构具备了应对流感大流行的基本专业技术能力,但仍存在人才队伍数量不足、应急物资储备机制不完善、监测系统建设东西部发展不均衡、基层流感病毒检测能力薄弱等问题,亟需加强和改进。     

Pandemic influenza A/H1N1 vaccine administered sequentially or simultaneously with seasonal influenza vaccine to HIV-infected children and adolescents

In order to evaluate the immunogenicity, safety and tolerability of the 2009 A/H1N1 MF59-adjuvanted influenza vaccine administered sequentially or simultaneously with seasonal virosomal-adjuvanted influenza vaccine to HIV-infected children and adolescents, 36 HIV-infected children and adolescents, and 36 age- and gender-matched healthy controls were randomised 1:1 to receive the pandemic vaccine upon enrolment and the seasonal vaccine one month later, or to receive the pandemic and seasonal vaccines simultaneously upon enrolment. Seroconversion and seroprotection rates against the pandemic influenza A/H1N1 virus were 100% two months after vaccine administration in both groups, regardless of the sequence of administration. Geometric mean titres against pandemic and seasonal antigens were significantly higher when the seasonal and pandemic vaccines were administered simultaneously than when the seasonal vaccine was administered alone. Local and systemic reactions were mild and not increased by simultaneous administration. In conclusion, the 2009 pandemic influenza A/H1N1 MF59-adjuvanted vaccine is as immunogenic, safe and well tolerated in HIV-infected children and adolescents as in healthy controls. Its simultaneous administration with virosomal-adjuvanted seasonal antigens seems to increase immune response to both pandemic and seasonal viruses with the same safety profile as that of the pandemic vaccine alone. However, because this finding cannot be clearly explained by an immunological viewpoint, further studies are needed to clarify the reasons of its occurrence.     

Coverage and side effects of influenza A(H1N1) 2009 monovalent vaccine among primary health care workers

In June 2009, WHO declared the maximum phase alert against H1N1 pandemic flu. Health care workers (HCWs) are considered a strategic target for prevention of the occurrence of H1N1 influenza since they had the greatest risk of acquiring infection. The objectives of our study were (1) identifying the uptake of influenza A(H1N1) 2009 monovalent vaccine by primary health care workers in the southern part of Cordoba, and (2) reporting of the adverse events occurred after vaccination. We followed 240 HCWs in 12 primary health care centres at southern part of Cordoba for vaccine uptake and the occurrence of adverse events. The coverage rate with H1N1 vaccine was 20.5% which was lower compared to seasonal influenza vaccination rate 44.2% in 2009. Males had higher H1N1 vaccination rate compared to females with no significant difference. Senior HCWs complied more with seasonal influenza vaccine while this finding was not consistent with H1N1 vaccination. Multivariate analysis showed that the only independent variable that affected H1N1 vaccine was the compliance to the seasonal flu vaccine in the past three years with OR 5.1 and 95% CI (2.4-10.8). Adverse events occurred among 26.5% of those who complied with H1N1 vaccination. Those were local pain, irritation and induration at site of injection (38.5%), fever (15.4%), fever cough and rhinorrhea (15.4%) generalized pain and lumber pains (23.1%). The low vaccination rate in this study is consistent with previous studies done in many parts of the world and in Spain. Further studies should be done to explore the factors that hindered the uptake and resistance of HCWs to vaccination to H1N1 vaccine.     

Prevention of influenza virus shedding and protection from lethal H1N1 challenge using a consensus 2009 H1N1 HA and NA adenovirus vector vaccine

Vaccines against emerging pathogens such as the 2009 H1N1 pandemic virus can benefit from current technologies such as rapid genomic sequencing to construct the most biologically relevant vaccine. A novel platform (Ad5 [E1-, E2b-]) has been utilized to induce immune responses to various antigenic targets. We employed this vector platform to express hemagglutinin (HA) and neuraminidase (NA) genes from 2009 H1N1 pandemic viruses. Inserts were consensuses sequences designed from viral isolate sequences and the vaccine was rapidly constructed and produced. Vaccination induced H1N1 immune responses in mice, which afforded protection from lethal virus challenge. In ferrets, vaccination protected from disease development and significantly reduced viral titers in nasal washes. H1N1 cell mediated immunity as well as antibody induction correlated with the prevention of disease symptoms and reduction of virus replication. The Ad5 [E1-, E2b-] should be evaluated for the rapid development of effective vaccines against infectious diseases.