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Poliomyelitis (polio) is a highly infectious intestinal disease caused by the poliovirus. Poliovirus is transmitted by person-to-person spread mainly through the fecal–oral route, or, less frequently, by contaminated water or food. Humans are the only known reservoir of poliovirus, which is transmitted most frequently by persons with inapparent infections. Initial symptoms of polio include fever, fatigue, headache, vomiting, stiffness in the neck, and pain in the limbs. In a small proportion of cases (1 in 200 infections), poliovirus causes paralysis, which is often permanent. Instead of a cure for polio, it can only be prevented. The Polio vaccine, given multiple times, can protect a child for life.

BACKGROUND: China reduced hepatitis B virus (HBV) infection by 90% among children under 5 years old with safe and effective hepatitis B vaccines (HepB). In December 2013 this success was threatened by widespread media reports of infant deaths following HepB administration. Seventeen deaths and one case of anaphylactic shock following HBV vaccination had been reported. METHODS: We conducted a telephone survey to measure parental confidence in HepB in eleven provinces at four points in time; reviewed maternal HBV status and use of HepB for newborns in birth hospitals in eight provinces before and after the event; and monitored coverage with hepatitis B vaccine and other programme vaccines in ten provinces. RESULTS: HepB from the implicated company was suspended during the investigation which showed that the deaths were not caused by HepB vaccination. Before the event 85% respondents regarded domestic vaccines as safe decreasing to 26.7% during the event. During the height of the crisis 30% of parents reported being hesitant to vaccinate and 18.4% reported they would refuse HepB. Use of HepB in the monitored provinces decreased by 18.6% from 53 653 doses the week before the event to 43 688 doses during the week that Biokangtai HepB was suspended. Use of HepB within the first day of life decreased by 10% among infants born to HBsAg-negative mothers and by 6% among infants born to HBsAg-positive mothers. Vaccine refusal and HepB birth dose rates returned to baseline within 2 months; confidence increased but remained below baseline. CONCLUSIONS: The HBV vaccine event resulted in the suspension of a safe vaccine which was associated with a decline of parental confidence and refusal of vaccination. Suspension of a vaccine can lead to loss of confidence that is difficult to recover. Timely and credible investigation accompanied by proactive outreach to stakeholders and the media may help mitigate negative impact of future coincidental adverse events following immunization. (c) The Author 2016; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.

Background After more than 10 years without a case of wild poliovirus (WPV) in China, an outbreak occurred in 2011 in Xinjiang Uyghur Autonomous Region. Methods Acute flaccid paralysis (AFP) case surveillance was strengthened with epidemiological investigations and specimen collection and serological surveys were conducted among hospitalized patients. Results There were 21 WPV cases and 23 clinical compatible polio cases reported. WPV was isolated from 14 contacts of AFP cases and 13 in the healthy population. Incidence of WPV and clinical compatible polio cases were both highest among children

To the Editor: Tibet is located in the Qinghai-Tibet Plateau of western People’s Republic of China and has been internationally recognized as a Japanese encephalitis (JE)–nonendemic area because the average altitude is thought to be too high to facilitate the cycle of Japanese encephalitis virus (JEV) between mosquitoes and vertebrates (1,2). In addition, JE is a reportable infectious disease in China, and no clinically confirmed case has been reported in Tibet since establishment of a national case reporting system in 1951 (3,4). Neither the mosquito vector of JEV nor JEV isolates have been described in Tibet. In this study, JEV was isolated from Culex tritaeniorhynchus mosquitoes, the main vectors of JEV, collected in Tibet. Serologic assays detected anti-JEV antibodies in a large number of human and porcine serum samples collected in this region. These data demonstrate that JEV is currently circulating in Tibet. During August 5–15, 2009, mosquitoes were collected in Mainling County (altitude 2,900 m) and Medog County (altitude 1,000 m) in the Nyingchi area of Tibet. A total of 4,089 mosquitoes representing 7 species (Cx. tritaeniorhynchus, Cx. pipiens pallens, Cx. bitaeniorhynchus, Armigeres obturbans, Anopheles maculatus maculates, An. peditaeniatu, and Aedes albopictus) from 4 genera were collected in this study. The dominant mosquito species detected in Medog County was Cx. tritaeniorhynchus (2,442 [71.1%] of 3,436 mosquitoes collected there) (Table); no previous reports have described this species in Tibet. A total of 653 mosquitoes were collected in Mainling County, of which 489 (74.9%) were Armigeres obturban. No Cx. tritaeniorhynchus mosquitoes were collected in Mainling County. Table Results from testing of mosquitoes, humans, and pigs for JEV, Nyingchi area, Tibet, People’s Republic of China, 2009* Mosquitoes were homogenized in 97 pools by using TissueLyser (QIAGEN, Hilden, Germany) and screened with reverse transcription–PCR (RT-PCR) by using seminested primers designed to detect the JEV PreM gene (5). One Cx. tritaeniorhynchus pool, XZ0938, collected in Medog County was positive by PCR. Isolation of virus was conducted from PCR-positive sample by injecting mosquito homogenate supernatants into monolayers of BHK-21 and C6/36 cells. The supernatant of pool XZ0938 caused cytopathic effects in BHK-21 and C6/36 cells in successive cell passages. The complete genome of 10,965 nt was sequenced (GenBank accession no. {"type":"entrez-nucleotide","attrs":{"text":"HQ652538","term_id":"337263366","term_text":"HQ652538"}}HQ652538) as described (6), which included a 96-nt 5′ nontranslated region and a 570-nt 3′ nontranslated region. The single open reading frame coded for a polyprotein of 3,432 aa. Compared with the complete genome sequences of 62 known JEV isolates, the nucleotide sequence identity varied from 83.6% to 97.8% and amino acid sequence identity from 94.9% to 99.7%. Phylogenetic trees derived from nucleotide sequences of the complete genome of JEV strains indicated that XZ0938 was a member of genotype I JEV. A more detailed analysis indicated that the Tibet JEV is most closely related to JEV isolates KV1899 (1999, Korea, {"type":"entrez-nucleotide","attrs":{"text":"AY316157","term_id":"32187331","term_text":"AY316157"}}AY316157), and JEV/sw/Mie/41/2002 (2002, Japan, {"type":"entrez-nucleotide","attrs":{"text":"AB241119","term_id":"81687252","term_text":"AB241119"}}AB241119) (data not shown). To determine whether local residents were infected by JEV, 248 human serum samples were collected in Mainling and Medog Counties from healthy persons. Neutralizing antibody against JEV was tested by 90% plaque-reduction neutralization tests by using standard methods (7). Serum samples were tested with serial 2-fold dilutions from 1 to 5. Diluted serum was mixed with equal volumes of culture medium containing JEV P3 strain. The samples were considered positive when the neutralizing antibody titers >10. Sixty-eight positive samples were determined by 90% plaque-reduction neutralization tests, which constituted 68 (27.4%) of all 248 serum samples. Twenty-two (22.0%) of 100 and 46 (31.1%) of 148 serum samples in Mainling and Medog Counties, respectively, were positive (Table). Currently, the local population is not vaccinated against JEV (8) because Tibet is considered a JE-nonendemic area (1–4). The observation that 68 (27.4%) of 248 serum samples from healthy humans contained neutralizing antibody against JEV at titers >10 suggests that this population is subject to substantial levels of subclinical JEV infection. To determine the present situation of JEV infection in local pigs, we analyzed 66 serum samples collected from piglets 1–6 months of age in Mainling and Medog Counties; immunoglobulin M antibodies against JEV were detected by capture ELISA as described (9). That 22 (33.3%) of 66 piglet serum samples were positive for immunoglobulin M against JEV suggested that local pigs have been newly infected by JEV in 2009 and have participated in the cycles of JEV in the local area (Table). JE is a global public health issue that has spread to >20 countries in Asia (6,10). In this study, we present evidence that JEV has extended its geographic range to Tibet, a region that previously was believed to be free of JE because of its elevation. Factors such as global warming, increased pig farming, and increased tourism and transportation may have contributed to the emergence of JE in Tibet. Conditions in Tibet, including the presence of the primary vector (Cx. tritaeniorhynchus mosquitoes), abundant amplification hosts (pig), and a naive population that has not been vaccinated against JEV, present the possibility for JE outbreaks. Increased surveillance for JE in this region is needed.

Background After being polio free for more than 10 years, an outbreak following importation of wild poliovirus (WPV) was confirmed in Xinjiang Uygur Autonomous Region, China, in 2011. Methods A cross-sectional study was conducted prior to supplementary immunization activities (SIAs), immediately after the confirmation of the WPV outbreak. In selected prefectures, participants aged ≤60 years old who visited hospitals at county-level or above to have their blood drawn for reasons not related to the study, were invited to participate in our study. Antibody titers ≥8 were considered positive. Results Among the 2,611 participants enrolled, 2,253 (86.3%), 2,283 (87.4%), and 1,989 (76.2%) were seropositive to P1, P2 and P3 respectively, and 1744 (66.8%) participants were seropositive to all the three serotypes. Lower antibody seropositivities and geometric mean titers were observed in children

The last case of infection with wild-type poliovirus indigenous to China was reported in 1994, and China was certified as a poliomyelitis-free region in 2000. In 2011, an outbreak of infection with imported wild-type poliovirus occurred in the province of Xinjiang.We conducted an investigation to guide the response to the outbreak, performed sequence analysis of the poliovirus type 1 capsid protein VP1 to determine the source, and carried out serologic and coverage surveys to assess the risk of viral propagation. Surveillance for acute flaccid paralysis was intensified to enhance case ascertainment.Between July 3 and October 9, 2011, investigators identified 21 cases of infection with wild-type poliovirus and 23 clinically compatible cases in southern Xinjiang. Wild-type poliovirus type 1 was isolated from 14 of 673 contacts of patients with acute flaccid paralysis (2.1%) and from 13 of 491 healthy persons who were not in contact with affected persons (2.6%). Sequence analysis implicated an imported wild-type poliovirus that originated in Pakistan as the cause of the outbreak. A public health emergency was declared in Xinjiang after the outbreak was confirmed. Surveillance for acute flaccid paralysis was enhanced, with daily reporting from all public and private hospitals. Five rounds of vaccination with live, attenuated oral poliovirus vaccine (OPV) were conducted among children and adults, and 43 million doses of OPV were administered. Trivalent OPV was used in three rounds, and monovalent OPV type 1 was used in two rounds. The outbreak was stopped 1.5 months after laboratory confirmation of the index case.The 2011 outbreak in China showed that poliomyelitis-free countries remain at risk for outbreaks while the poliovirus circulates anywhere in the world. Global eradication of poliomyelitis will benefit all countries, even those that are currently free of poliomyelitis.

To analyze the prevalence season and trend of meningococcal disease in China by epidemic years from 2004 to 2008 in order to provide scientific basis for making strategies ofmeningococcal disease prevention and control.The incidence numbers of meningococcal disease were calculated by weeks, epidemic years and areas. The seasonality and prevalence trends of meningococcal disease were analyzed by circular distribution.The incidence trend of meningococcal disease had obvious seasonality in China (P0.01). The peak of meningococcal disease were different by epidemic years and areas (P0.01). There were no association between annual incidence rates and seasonality.We should strength meningococcal disease surveillance before epidemic peak period,and put immunoprophylaxis first and carry out comprehensive measures of prevention and control.

To evaluate quality of surveillance and emendate rates of birth and death of population of the Three Gorges area.Data on the two samples collected were designed based on principle of capture-recapture method. An investigation of missing report of birth and death was conducted in 7061 families selected through stratified random sampling method. We collected and registered the data of birth and death in every family investigated and checked with correlative records reported in disease surveillance system of the Three Gorges area. The missing report rates and the 95% confidence intervals of birth rate and death rate were calculated.The underreporting rates of birth and death were 13.91% and 15.60% and death of infant was 33.33%. The emended birth rate was 8.92 per thousandth and the 95% confidence interval of birth rate was 8.38 per thousandth-9.45 per thousandth. The emended report rate of death was 6.88 per thousandth and the collectivity 95% confidence interval was 6.37%-7.38 per thousandth.Results showed that the quality of birth and death in the disease surveillance reporting system of Three Gorges area was competent to the quality level of the standard set for national disease surveillance system. The birth and death rates of population in the Three Gorges area were under 10.00 per thousandth.