Transmission of COVID-19 in the terminal stages of the incubation period: A familial cluster.

We report a familial cluster of 2019 novel coronavirus disease (COVID-19) to assess its potential transmission during the incubation period. The first patient in this familial cluster was identified during the presymptomatic period, as a close contact of a confirmed patient. Five family members had close contact with this first patient during his incubation period, with four of them confirmed positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the subsequent sampling tests.

Resurgence of scarlet fever in China: a 13-year population-based surveillance study.

BACKGROUND: A re-emergence of scarlet fever has been noted in Hong Kong, South Korea, and England, UK, since 2008. China also had a sudden increase in the incidence of the disease in 2011. In this study, we aimed to assess the epidemiological changes before and after the upsurge. We also aimed to explore the reasons for the upsurge in disease in 2011, the epidemiological factors that contributed to it, and assess how these could be managed to prevent future epidemics. METHODS: In this observational study, we extracted the epidemiological data for all cases of scarlet fever between 2004 and 2016 in China from the Chinese Public Health Science Data Center, the official website of National Health Commission of the People's Republic of China, and the National Notifiable Infectious Disease Surveillance System. These data had been collected from 31 provinces and regions in China and included geographical, seasonal, and patient demographic information. We used descriptive statistical methods and joinpoint regression to examine the spatiotemporal patterns and annual percentage change in incidence of the upsurge of disease across China. FINDINGS: Between Jan 1, 2004, and Dec 31, 2016, 502 723 cases of scarlet fever, with ten fatalities, were reported in China, resulting in an annualised average incidence of 2·8807 per 100 000 people. The annual average incidence increased from 1·457 per 100 000 people in 2004 to 4·7638 per 100 000 people in 2011 (incidence rate ratio [IRR] 3·27, 95% CI 3·22-3·32; p<0·0001), peaking in 2015 (5·0092 per 100 000 people). The annual incidence after the 2011 upsurge of scarlet fever, between 2011 and 2016, was twice the average annual incidence reported between 2004 and 2010 (4·0125 vs 1·9105 per 100 000 people; IRR 2·07, 95% CI 2·06-2·09; p<0·0001). Most cases were distributed in the north, northeast, and northwest of the country. Semi-annual patterns were observed in May-June and November-December. The median age at onset of disease was 6 years, with the annual highest incidence observed in children aged 6 years (49·4675 per 100 000 people). The incidence among boys and men was 1·54 greater than that among girls and women before the upsurge, and 1·51 times greater after the upsurge (p<0·0001 for both). The median time from disease onset to reporting of the disease was shorter after the upsurge in disease than before (3 days vs 4 days; p=0·001). INTERPRETATION: To our knowledge, this is the largest epidemiological study of scarlet fever worldwide. The patterns of infection across the country were similar before and after the 2011 upsurge, but the incidence of disease was substantially higher after 2011. Prevention and control strategies being implemented in response to this threat include improving disease surveillance and emergency response systems. In particular, the school absenteeism and symptom monitoring and early-warning system will contribute to the early diagnosis and report of the scarlet fever. This approach will help combat scarlet fever and other childhood infectious diseases in China. FUNDING: National Key R&D Plan of China Science and key epidemiological disciplines of Zhejiang Provincial Health of China.

Risk factors for avian influenza virus in backyard poultry flocks and environments in Zhejiang Province, China: a cross-sectional study.

BACKGROUND: Human infection of avian influenza virus (AIV) remains a great concern. Although live poultry markets are believed to be associated with human infections, ever more infections have been reported in rural areas with backyard poultry, especially in the fifth epidemic of H7N9. However, limited information is available on backyard poultry infection and surrounding environmental contamination. METHODS: Two surveillance systems and a field survey were used to collect data and samples in Zhejiang Province. In total, 4538 samples were collected by surveillance systems and 3171 from the field survey between May 2015 and May 2017, while 352 backyard poultry owners were interviewed in May 2017 by questionnaire to investigate factors influencing the prevalence of avian influenza A virus and other AIV subtypes. RT-PCR was used to test the nucleic acids of viruses. ArcGIS 10.1 software was used to generate maps. Univariate and logistic regression analyses were conducted to identify risk factors for AIV infection. RESULTS: Of the 428 poultry premises observed by the surveillance system, 53 (12.38%) were positive for influenza A virus. Of the 352 samples from poultry premises observed by field survey, 13 (3.39%) were positive for influenza A virus. The prevalence of AIV was unevenly distributed and the dominant subtype differed among cities. Eastern (Shaoxing and Ningbo) and southern (Wenzhou) cities exhibited a higher prevalence of AIV (16.33, 8.94, and 7.30% respectively). Contamination of AIV subtypes was most severe in January, especially in 2016 (23.26%, 70/301). The positive rate of subtype H5/H7/H9 was 2.53% (115/4538). Subtype H5 was the least prevalent, while subtypes H7 and H9 had similar positivity rates (1.50 and 1.32% respectively). Poultry flocks and environmental samples had a similar prevalence of AIV (4.46% vs 5.06%). The type of live birds was a risk factor and the sanitary condition of the setting was a protective factor against influenza A contamination. CONCLUSIONS: AIV subtypes were prevalent in backyard poultry flocks and surrounding environments in Zhejiang Province. The types of live birds and sanitary conditions of the environment were associated with influenza A contamination. These findings shine a light on the characteristics of contamination of AIV subtypes and emphasize the importance of reducing AIV circulation in backyard poultry settings.

Genotypic and Epidemiological Trends of Acute Gastroenteritis Associated with Noroviruses in China from 2006 to 2016.

There are periodical norovirus-associated acute gastroenteritis outbreaks around the world. This study aimed to analyze the molecular and epidemiological features of norovirus infections in China during 2006-2016. We extracted epidemiological data from 132 norovirus outbreaks and the norovirus genotyping for 1291 sequences in China over the past ten years. A total of 132 norovirus outbreaks (8133 cases) were reported in China, where the east and south regions were most affected [47.7% (63/132)]. The highest number of outbreaks occurred in 2015. A seasonal pattern has been observed, with a peak from November to the following March. Most of the outbreaks occurred in middle and primary schools, accounting for 28.8% (38/132), and 28.0% (37/132) of outbreaks, respectively. The dominant age group was 10 to 19 years old, responsible for 75.7% (933/1232) of cases. Generally, the dominant genotypes was GII, for 81.9% (1058/1291) of sequences. G II.4 was the predominant genotype in China from 2004 to 2014. However, the GII.17 became more prevalent starting in 2014. Norovirus-associated acute gastroenteritis increased sharply in recent years caused by the emergence of GII.17, but epidemiological features have not changed during 2006-2016. Vigilant surveillance should be strengthened to promptly detect any variation.

Comparative Epidemiology of Human Fatal Infections with Novel, High (H5N6 and H5N1) and Low (H7N9 and H9N2) Pathogenicity Avian Influenza A Viruses.

This study aimed to assess the mortality risks for human infection with high (HPAI) and low (LPAI) pathogenicity avian influenza viruses. The HPAI case fatality rate (CFR) was far higher than the LPAI CFR [66.0% (293/444) vs. 68.75% (11/16) vs. 40.4% (265/656) vs. 0.0% (0/18) in the cases with H5N1, H5N6, H7N9, and H9N2 viruses, respectively; p < 0.001]. Similarly, the CFR of the index cases was greater than the secondary cases with H5N1 [100% (43/43) vs. 43.3% (42/97), p < 0.001]. Old age [22.5 vs. 17 years for H5N1, p = 0.018; 61 vs. 49 years for H7H9, p < 0.001], concurrent diseases [18.8% (15/80) vs. 8.33% (9/108) for H5N1, p = 0.046; 58.6% (156/266) vs. 34.8% (135/388) for H7H9, p < 0.001], delayed confirmation [13 vs. 6 days for H5N1, p < 0.001; 10 vs. 8 days for H7N9, p = 0.011] in the fatalities and survivors, were risk factors for deaths. With regard to the H5N1 clusters, exposure to poultry [67.4% (29/43) vs. 45.2% (19/42), p = 0.039] was the higher risk for the primary than the secondary deaths. In conclusion, old age, comorbidities, delayed confirmation, along with poultry exposure are the major risks contributing to fatal outcomes in human HPAI and LPAI infections.

Enterovirus 71 infection causes severe pulmonary lesions in gerbils, meriones unguiculatus, which can be prevented by passive immunization with specific antisera.

Neurogenic pulmonary edema caused by severe brainstem encephalitis is the leading cause of death in young children infected by Enterovirus 71 (EV71). However, no pulmonary lesions have been found in EV71-infected transgenic or non-transgenic mouse models. Development of a suitable animal model is important for studying EV71 pathogenesis and assessing effect of therapeutic approaches. We had found neurological disorders in EV71-induced young gerbils previously. Here, we report severe pulmonary lesions characterized with pulmonary congestion and hemorrhage in a gerbil model for EV71 infection. In the EV71-infected gerbils, six 21-day-old or younger gerbils presented with a sudden onset of symptoms and rapid illness progression after inoculation with 1×105.5 TCID50 of EV71 via intraperitoneal (IP) or intramuscular (IM) route. Respiratory symptoms were observed along with interstitial pneumonia, pulmonary congestion and extensive lung hemorrhage could be detected in the lung tissues by histopathological examination. EV71 viral titer was found to be peak at late stages of infection. EV71-induced pulmonary lesions, together with severe neurological disorders were also observed in gerbils, accurately mimicking the disease process in EV71-infected patients. Passive transfer with immune sera from EV71 infected adult gerbils with a neutralizing antibody (GMT=89) prevented severe pulmonary lesion formation after lethal EV71 challenge. These results establish this gerbil model as a useful platform for studying the pathogenesis of EV71-induced pulmonary lesions, immunotherapy and antiviral drugs.

Comparative epidemiology and virology of fatal and nonfatal cases of hand, foot and mouth disease in mainland China from 2008 to 2014.

This study aimed to analyze the epidemiology and virology of fatal and nonfatal hand, foot, and mouth disease (HFMD) cases in Mainland China. A total of 10,714,237 survivors and 3046 deaths were reported from 2008 to 2014 June, with a case fatality rate of 0.03%. The morbidity of the survivors increased from 37.6/100,000 in 2008 to 139.6/100,000 in 2013 and peaked in 2012 at 166.8/100,000. However, the mortality varied around 0.03-0.04/100,000 across the time. Most of the survivors were distributed in the southern and eastern China, predominantly in the Guangxi and Hainan Province, whereas deaths were dominant in southern (Guangxi) and southwestern (Guizhou) China. The two groups showed similar seasonal fluctuations from 2008 to 2014, peaking in spring and early summer. Of the total cases, 93.97% were children less than 5 years of age, with those ≤ 2 years old accounting for 60.08% versus 84.02% in the survivor and death groups, respectively. Boys were at higher risk of infection than girls in both groups. Five years of virological surveillance showed that 43.73%, 22.04%, and 34.22% of HFMD cases were due to EV71, CoxA16 and other enteroviruses, respectively. EV71 was encountered in most deaths, with no substantial effect of age, gender, month, and year on incidence. Subgenotype C4a was the prevalent EV71 strain in Mainland China, with no significant difference in the VP1 gene related to virulence between the two groups. In conclusion, based on the largest population study, fatal and nonfatal HFMD cases, mainly caused by C4a of EV71, are circulating in Mainland China with a low-cause fatality rate.

[Clinical and epidemiological characteristics of the 6 confirmed human cases with novel influenza A (H7N9) virus infection in Zhejiang].

OBJECTIVE: To explore the clinical spectrum, geographic location of human H7N9 avian influenza as well as the characteristics of population at high risk of infection, in order to develop strategies for the prevention and control of the infection. Clinical and epidemiological characteristics on the 6 confirmed human cases in Zhejiang were also analyzed. METHODS: Real-time fluorescent quantitative PCR was used to test the nucleic acid of human H7N9 avian influenza infection, from pharyngeal swabs of the patients and their close contacts. Face to face interview and descriptive method were used to collect related clinical and epidemiological data. Statistical analysis was performed by SPSS 17.0. RESULTS: Six confirmed cases were distributed in Hangzhou and Huzhou cities. The 6 confirmed human cases, including 5 males and 1 female were all confirmed with novel influenza A (H7N9) virus infection, with an average age as 60.83 years (with median as 64.50 years). Cough was the most common initial symptom to be noticed. The clinical manifestations would include fever, dizziness, pain of muscles, coughing, expectoration and short of breath. All the X-ray chest films showed severe pneumonia, and 5 of them having had other chronic diseases. None of the cases admitted to have had a history of exposure to ill/death avians. However, all of the cases had been frequently exposed to the agricultural-byproduct-trading-markets where the positive rate of novel influenza A (H7N9) virus in environmental specimens was up to 43.21%. 32 of the 375 close contacts (8.53%) to the 6 cases appeared abnormal symptoms, but no positive result related to novel influenza A (H7N9) virus nucleic acid was detected from their throat swabs. CONCLUSION: Acute infection on the respiratory system seemed the main clinical manifestation. Elderly men, especially those with chronic diseases were under high risk of human infection with H7N9 avian influenza. The source of infection might be associated with the exposure to poultry. There was still lack of evidence to confirm the route of person to person transmission on H7N9 avian influenza.

Patterns of polymorphism and divergence in the VP1 gene of enterovirus 71 circulating in the Asia-Pacific region between 1994 and 2013.

Enterovirus 71 has been implicated in several outbreaks of hand, foot and mouth disease in the Asia-Pacific region. The present study aimed to achieve comprehensive evolutionary dynamic aspects of EV71 during 1994-2013, based on phylogenetic analyses of the VP1 sequences. The results indicated that 4 genotypes, namely C4, C1, C2 and B4 are the predominant strains, especially in Southeast Asian countries. No common ancestor was shared in different countries. Fourteen sites of substitutions were detected in the VP1 gene sequences; including the most common sites related to neutralization at position V249I [47.1% (189/401)] and A289T [42.6% (171/401)]. However, the sites Q22H and Q22R associated with increased virulence were recognized only in 13.7% (55/401) and 18% (72/401), respectively. None of the above mutations seemed to become fixed because the ratio of Ka/Ks was greater than 1.0. Mutations K43E, A58T, S184T, and T240S could possibly change the spatial structure. Two mutations, G145E and T240S, could obviously affect the hydrophobicity of VP1 and thus alter the EV71 immunoreactivity. In conclusion, the VP1 gene of EV71 strains circulating in the Asia-Pacific region during 1994-2013, showed polymorphisms and divergence with very slow evolution rate, which may be one of the reasons for periodic outbreaks in this area.

Pandemic influenza A(H1N1) 2009 virus in pregnancy.

Two hundred fourteen abstracts and 87 full texts regarding pregnant women infected with pandemic influenza A(H1N1) 2009 virus were systematically reviewed by using a PubMed search and assessing pandemic, clinical, laboratory test, vaccine, and control experiences. Both policy and health education were excluded. This review counted the total number of pregnant cases from different countries and analyzed their epidemic features, including trimester distribution, morbidity, hospitalization, intensive care unit admissions, maternal mortality, underlying diseases, complications, high-risk factors for death, pregnancy outcome, and clinical symptoms compared with the previous pandemic seasonal influenza A/H1N1 as compared with the general population. Early identification and treatment were the most important factors in different countries and areas examined. The vaccine and antiviral drugs that have been the most efficient means to control the novel virus appear to be safe but require more extensive study. In the future, the focus should be placed on understanding vertical transmission and the severe mechanisms.

Evidence for H5 avian influenza infection in Zhejiang province, China, 2010-2012: a cross-sectional study.

BACKGROUND: The first outbreak of H5N1 highly-pathogenic avian influenza (HPAI) virus associated with several human deaths occurred in 1997 in Hong-Kong, China. While H5N1 virus infection in poultry workers has been studied in some detail, little is known about the environmental risk factors of the H5 avian influenza virus infection in China. METHODS: A cross-sectional study was performed to evaluate the environmental load of H5 viruses in poultry-contaminated environments and to explore potential risk factors associated with infection in poultry workers between October 2010 and March 2012. Serum and environmental samples were collected in Zhejiang province, China. The hemagglutination inhibition (HI) assay was used to analyze human sera for antibodies against H5N1 virus [A/Hubei/1/2010 (H5N1) and A/Anhui/1/2005 (H5N1)]. All participants were interviewed with a standardized questionnaire to collect information on exposure to poultry. H5 Avian influenza virus in the environmental samples was detected by real time RT-PCR. RESULTS: One hundred and five of 3,453 environmental samples (3.0%) tested positive for H5 avian influenza virus. Fifty-five of 1,169 subjects (4.7%) tested seropositive for anti-H5N1 antibodies. A statistically significant difference in H5 virus detection rate was found among the different environments sampled (<0.001), with the highest showed in live bird markets (68.6%). Detection rate varied according to the source of samples, sewage (9.5%), drinking water (19.0%), feces (19.0%), cage surface (25.7%), and slaughtering chopping boards (15.2%), respectively. Direct or close contact with poultry (OR =5.20, 95% CI, 1.53-17.74) and breeding numerous poultry (OR =3.77, 95% CI, 1.72-8.73) were significantly associated with seroprevalence of antibodies to avian influenza virus A (H5N1). CONCLUSIONS: The number of birds bred more than 1,000 and direct or close contact with poultry in the workplace or the environment would be a potential risk of H5N1 infection.

Two adenovirus serotype 3 outbreaks associated with febrile respiratory disease and pharyngoconjunctival fever in children under 15 years of age in Hangzhou, China, during 2011.

Adenovirus serotype 3 and 7 outbreaks have occurred periodically in northern, eastern, and southern China since 1955, but there has been no report since the adenovirus serotype 7 outbreak first occurred in Hangzhou, China, in 1991. Here we explored the epidemiology and etiology of two adenovirus serotype 3 outbreaks in Hangzhou in 2011. One acute respiratory outbreak was found in Chun'an County, where a total of 371 cases were confirmed in 5 of 23 towns from 4 to 31 May 2011. The outbreak affected 18.57% (13/70) of schools and 14.49% (90/621) of classes. The incidence was 5.18% (371/7,163). The population was distributed among individuals ages 7 to 15 years. No parents or teachers were infected. Another pharyngoconjunctival fever outbreak was discovered in the Chenjinglun Swimming Center located in the Xihu District between 1 and 15 July 2011. A total of 134 cases were confirmed in 900 amateur swimmers, with an incidence of 14.89% (134/900). The ages ranged from 4 to 9 years. The two outbreaks had no severe complications or death. The viruses in 66.67% (10/15) of throat swabs from children with acute respiratory infections and 100% (10/10) of the swabs from children with pharyngoconjunctival fever were confirmed to be adenovirus serotype 3 with 100% homology by PCR. Of these samples, 60.0% (12/20) had a classical characteristic cytopathic effect, presented as grape-like clusters at 72 h after infection in HEp-2 cells. In conclusion, the acute respiratory infection and pharyngoconjunctival fever outbreak in Hangzhou were caused by the completely homologous type 3 adenovirus in subgenus B. Moreover, these outbreaks demonstrated rapid transmission rates, possibly due to close contact and droplet transmission.

Evolutionary characterization of human H1N1 influenza virus hemagglutinin genes isolated from 1947 to 2009 in China.

OBJECTIVE: Our aim was to reveal the molecular characteristics of human H1N1 influenza virus hemagglutinin (HA) genes from 1947 to 2009 in China. METHODS: 129 HA gene sequences were downloaded from NCBI's GenBank and analyzed by DNASTAR software. Additionally, the three-dimensional structure of HA protein was predicted by the SWISS-MODEL service. RESULTS: First, 2009 Chinese HA genes were 99% identical to those of Mexican and American ones; their key sites remained highly conserved. Second, 50 Chinese strains from 1947 to 2009 clustered by the year of isolation, and 2009 strains had only 70% identity to 1947-2008 ones. Third, over the past 60 years, 3 receptor-binding (RB) sites and 2 of the 8 glycosylation sites (amino acids 279 and 290) underwent considerable changes while the cleavage sites remained stable. Fourth, the human HA sequences differed completely from swine and avian isolates. Finally, the mutation of cleavage sites can change the three-dimensional structures, but single mutations cannot. CONCLUSIONS: Thus, in the past 60 years, Chinese H1N1 influenza HA genes kept stable with high affinity and low pathogenicity to human except changes in 2 glycosylation and 3 RB sites which were associated with the pandemic strength, range and host specificity of viruses.

2009 pandemic characteristics and controlling experiences of influenza H1N1 virus 1 year after the inception in Hangzhou, China.

This paper described the epidemiology and controlling experiences of influenza H1N1 in Hangzhou in the past 1 year. A total of 2,078 cases confirmed by real-time quantitative PCR till March 31, 2010, were analyzed by SPSS 12.0 software. During the early pandemic stage, a patient must be tested for H1N1 nucleic acid once he/she had influenza-like symptoms with the epidemiological history in 7 days, and be diagnosed if it was positive. But in the pandemic peak, we made efforts to identify and save severe cases combined with pneumonia or hypoxemia or respiratory failure or septic shock or multiple organ dysfunctions and failure. In general, the prevalence was 2.77/100,000 (2,078/7,510,844); severity rate, 10.44% (217/2,078); fatality rate, 0.48% (10/2,078). The carrier and secondary attack rate were 9.52% (58/612) and 8.66% (53/612), respectively. About 50% of serious cases and 100% of deaths had the basic underlying diseases: cardiovascular diseases, 13.66% (25/217); chronic lung disease, 12.02% (22/217); pregnant, 7.1% (13/217). Of all cases aged from 1 month to 89 years, 52.99% (1,435/2,708) were in the 10-29 years, with most of them distributed in downtown area. The timeline showed two epidemic peaks occurred in September and November 2009, respectively. Furthermore, the hemagglutinin gene remained 99% identical with the American and vaccine strains, but only 70% with the 1947-2008 Chinese strains. In conclusion, Hangzhou pandemic influenza H1N1 was caused by the highly conserved virus, with low prevalence, transmission, and mortality, because we took efficient controlling methods.

A serological and molecular survey of hepatitis B in children 15 years after inception of the national hepatitis B vaccination program in eastern China.

The emergence of mutations in the hepatitis B virus (HBV) S gene has threatened the long-term success of vaccination programs since the worldwide introduction of effective vaccines against hepatitis B. This study was conducted on 5,407 children (0-8 years old) in eastern China in 2007. We analyzed the prevalence of HBsAg, anti-HBs, and "a"-determinant mutations in the HBV S gene by microparticle enzyme immunoassays, PCR, and DNASTAR software. The total HBsAg prevalence was 1.52% (82/5,407) in the children and increased with age. In contrast, the positive rate (65.42%, 2,374/3,629) and the titers of anti-HBs decreased with age. The predominant infection was HBV of genotype C and serotype adr (45/51; 88% of cases). Mutations of I126T, amino acid 137 (nt553T deletion mutation), G145A, G145R, and F158S were found in the children; the mutations of amino acid 137 and F158S have not been reported previously. The total prevalence of mutant strains was 14% (7/51). To investigate whether the infection resulted from maternal transmission, we compared the S gene sequences in 16 mother-child pairs. Fourteen mother-child pairs exhibited the same HBV genotype, with 99.5-100% sequence homology in the S gene, while two pairs exhibited different genotypes. This study suggested that the hepatitis B vaccination strategies in eastern China have been successful. Although the emergence of "a"-determinant mutations in the HBV S gene have resulted in HBV infection in immunized children, this does not pose a threat to the vaccination strategies. The HBV-infected children had contracted the infection via vertical transmission.

Influence of HBV gene heterogeneity on the failure of immunization with HBV vaccines in eastern China.

The influence of hepatitis B virus (HBV) gene heterogeneity on the failure of HBV vaccination in eastern China remains unknown. Here, we assigned 78 hepatitis B surface antigen (HBsAg)-carrier mothers to two groups: 41 mothers from whom transmission of HBV to their children was successfully prevented and 37 mothers whose children were HBsAg positive 1 year after HBV vaccination. The DNA loads in mothers of the failure group (4.17E + 07 copies/ml) were significantly higher than those in the success group (8.40E + 06 copies/ml). However, no difference was found in the S gene mutation rate and genotypes between the groups. Interestingly, Thr123Ala and Gly145Arg were observed only in failure-group mothers, whereas Thr126Asn, Thr126Ser, Thr143Asn, Asp144Gly, and Asp144Ala were seen in the success group. Thus, high viral load is an important risk factor for HBV vaccination failure, which is correlated with the positions of mutations in the S gene, but not with mutant frequencies or genotypes.

[Study on the kinesis of cellular immunity in adults vaccinated with recombinant hepatitis B vaccine].

OBJECTIVE: To evaluate the kinesis of cellular immunity in adults who were vaccinated with yeast recombinant hepatitis B(rHB) vaccine and the correlation between cellular and humoral immune responses induced by the vaccine. METHODS: Eight adults were vaccinated with rHB vaccine according to 0, 1,2 month schedule. The peripheral blood mononuclear cells(PBMCs) were collected at the 3, 8, 21, 34 and 65 days after the first dose. The high purity of CD4+ and CD8+ T cells obtained by sorting from PBMCs were restimulated with recombinant hepatitis B surface antigens (rHBsAg) or peptides. The spot forming cell (SFC) of IFN-gamma, IL-2 and IL-4 of CD4+ and CD8+ T cells were detected by enzyme-linked immunospot (ELISPOT). RESULTS: The characteristics of IFN-gamma, IL-2 and IL-4 of CD4+ and CD8+ T cells appeared different after immunization with rHB vaccine. IFN-gamma of CD8+ and CD4+ T cells could be detected early with stable SFC, while the IL-2 and IL-4 of CD4+ T cells appeared late but increased after the second and third dose of vaccination. The positive rate of IL-4 of CD4+ T cells were significantly correlated with the positive rate of anti-HBs, while the SFCs of IL-4 and IL-2 of CD4+ T cells were also significantly related to the titers of anti-FIBs. CONCLUSION: IFN-gamma could be detected early after rHB vaccination in adults, and the positive rates of IL-4 and IL-2 were correlated with that of anti-HBs.

[Study on the efficacy of hepatitis B virus vaccination and its influencing factors among children in rural area of Jiangsu province].

OBJECTIVE: To evaluate the efficacy of hepatitis B viruse (HBV) vaccination and its influencing factors among children in rural area of Jiangsu province. METHODS: Twenty-five hundred and twenty-two children born after 1998 in rural area were selected as the study population using multistage cluster sampling method. HBsAg and anti-HBs were detected by enzyme linked immunoassay (ELISA) and radio-immunoassay (RIA), respectively. Anti-HBs negative children were boosted using different hepatitis B vaccines and the efficacy was compared. Factors causing HBV infection in HBsAg positive children were also investigated. RESULTS: HBsAg positive rates in 1-7 year olds were 0.28%-1.28%, and the anti-HBs positive rates decreased from 76.7% to 45.5%. The HBsAg positive rate in children not timely vaccinated was significantly higher than those with HBV vaccine injection within 24 hours after birth (1.4% vs. 0.5%, P = 0.031). More than 90% of the anti-HBs negative children had protective level of anti-HBs after boosted with HBV vaccine. CONCLUSION: HBsAg positive rate in children born after 1998 in rural area of Jiangsu province decreased significantly, with an average of 0.8%. The reason for HBsAg carriage in children might be attributed to mother-to-infant transmission or not timely HBV vaccination.

[Interruption failure of heptitis B virus vaccination in mother-to-infant transmission and heptitis B virus genotypes and preC/BCP mutations].

OBJECTIVE: To investigate the association of heptitis B virus (HBV) genotypes and precore(PreC)/basal core promoter(BCP) mutation with interruption failure of HBV vaccination in mother-to-infant transmission. METHODS: A total number of 208 serum samples were collected from infants and mothers,including 16 infants who had become HBsAg-positive despite a complete and timely course of immunization and another 88 infants successfully protected from mother-to infant HBV transmission. HBV genotypes were determined by type-specific primers PCR method. PreC/BCP mutations were detected by direct sequencing of PCR products, and Clustal W 1.8 software was applied to analyzing the sequences. RESULTS: Of 16 mothers who were having vaccine failure infants, 15 (93.8%) were HBeAg positive and infected with genotype C (15/15, 100%). Among 88 mothers of having children being protected by vaccine, 51 (58.0%) were HBeAg positive, with 45.1% (23/51) of genotype C. The proportion of genotype C in HBeAg mothers of infants with vaccine failure, was significantly higher than that of mothers with vaccine protected infants (chi2 = 14.3, P = 0.003). However, the frequencies of T1762/A1764 mutations had no significant differences between genotype C HBeAg positive mothers with vaccine failure or protected infants (33.3% and 13.3%, respectively, P = 0.4). No A1896 mutation was found in these two groups. CONCLUSION: HBV genotype C might contribute to the immune failure of HBV vaccination in mother-to-infant transmission, while PreC/BCP mutation might not have correlation with it.

[Role of mutations on the "hepatitis B virus 'a' determinant hotpoint" to the efficacy of hepatitis B vaccine].

OBJECTIVE: To study how hepatitis B virus(HBV) 'a' determinant hotpoint mutations were influecing the hepatitis B vaccine efficacy. METHODS: Primers were designed in HBV conservative region, and the degenerate probes for detecting 16 'a' determinant hotpoint mutations were developed for gene chips. Sensitivity and specificity of the gene chips were evaluated by clone sequencing. Sera of 47 pairs of mothers and infants with immune failure and 323 mothers of children with immune protection of HB vaccine were detected by the gene chips. RESULTS: Result from clone sequencing demonstrated that the gene chips were specific for the detection of 'a' determinant hotpoint mutations. The wild type of HBV was still dominant, with the prevalence of 78.66%, and the mutation frequencies of 126A, 145R, 126S-1, 126S-2, 129H, 144A, and 129R were 11.27%, 5.76%, 5.28%, 4.56%, 1.20%, 0.72% and 0.24%, respectively. The prevalence of 126A mutation was significantly higher than that of other mutations(P < 0.01). No significant differences were found in mother-infant transmission rates of 126A, 126S-1, 126S-2 and 145R variants. CONCLUSION: The currently available hepatitis B vaccine could block mother-infant transmission of 126A, 126S and 145R variants. It appears that there is no need to develop a new hepatitis B vaccine against 126 and 145 variants at present, but the consistent epidemiological surveillance on HBV mutants should be carried out.