Effectiveness of SARS-CoV-2-inactivated vaccine and the correlation to neutralizing antibodies: A test-negative case-control study.

Severe acute respiratory syndrome coronavirus 2 breakthrough infection in highly vaccinated populations raises study on the effectiveness for inactivated vaccine, including effectiveness of the vaccine dose, the continuance of effectiveness, the effectiveness against severe/critical coronavirus disease 2019 and against secondary attacks. A population of 10 870 close contacts were investigated in a Delta variant's epidemic. The effectiveness of vaccination was estimated in a test-negative case-control study. In addition, serum was used to detect neutralizing antibodies, to explore their correlation to effectiveness. The vaccine effectiveness (VE) values were estimated for populations aged 12 years or older. The overall adjusted VE was 56.2% and a two-dose vaccine was more effective than a one-dose vaccine (56.7% vs. 43.8%). In addition, the population that got the second dose vaccine within 2 months showed higher VE than the population vaccinated for longer than 2 months (61.5% vs. 52.3%). Among the population who vaccinated 2 doses or within 2 months, a higher level of neutralizing antibodies was observed. For infected cases, vaccinated populations showed lower rates of transmission (2.63% vs. 4.36%). Further, those vaccinated cases, who were not found causing transmission, had a higher level of antibodies. The study provided a full view of the effectiveness of inactivated vaccines in a real-world setting. The time-related VE against infection and lower transmission of breakthrough vaccinated cases were observed, which may indicate that a necessity of a booster vaccine to maintain the effectiveness and high level of neutralizing antibody.

Incidence of human rabies and characterization of rabies virus nucleoprotein gene in dogs in Fujian Province, Southeast China, 2002-2012.

BACKGROUND: Rabies is a global fatal infectious viral disease that is characterized by a high mortality after onset of clinical symptoms. Recently, there has been an increase in the incidence of rabies in China. The aim of this study was to investigate the incidence of human rabies and characterize the rabies virus nucleoprotein gene in dogs sampled from Fujian Province, Southeast China from 2002 to 2012. METHODS: Data pertaining to human rabies cases in Fujian Province during the period from 2002 through 2012 were collected, and the epidemiological profiles were described. The saliva and brain specimens were collected from dogs in Quanzhou, Longyan and Sanming cities of the province, and the rabies virus antigen was determined in the canine saliva specimens using an ELISA assay. Rabies virus RNA was extracted from canine brain specimens, and rabies virus nucleoprotein gene was amplified using a nested RT-PCR assay, followed by sequencing and genotyping. RESULTS: A total of 226 human rabies cases were reported in Fujian Province from 2002 to 2012, in which 197 cases were detected in three cities of Quanzhou, Longyan and Sanming. ELISA assay revealed positive rabies virus antigen in six of eight rabid dogs and 165 of 3492 seemingly healthy dogs. The full-length gene fragment of the rabies virus nucleoprotein gene was amplified from the brain specimens of seven rabid dogs and 12 seemingly healthy dogs. Sequence alignment and phylogenetic analysis revealed that these 19 rabies virus nucleoprotein genes all belonged to genotype I, and were classified into three genetic groups. Sequencing analysis showed a 99.7% to 100% intra-group and an 86.4% to 89.3% inter-group homology. CONCLUSIONS: This study is the first description pertaining to the epidemiological characteristics of human rabies cases and characterization of the rabies virus nucleoprotein gene in dogs in Fujian Province, Southeast China. Our findings may provide valuable knowledge for the development of strategies targeting the prevention and control of rabies.

[Investigation and genetic identification on Babesia infection in rodents in some areas of Fujian Province].

Objective: To explore the status of Babesia infection in rodents and the genetic characteristics of Babesia spp. in Fujian Province. Methods: Rodents were captured by the night trapping method in Shaowu, Qingliu, Shunchang, Yong'an, Changle and Youxi during 2014-2015. The rodent species was identified, and information on the time and place of capture, species and sex of rodents was recorded. Blood samples was collected, in which the fragment of 18S rRNA gene of Babesia spp. was amplified by PCR. The PCR products were sequenced and the phylogenetic tree was constructed for homology analysis. Data on positive rate were analyzed with Chi-square or Fisher exact test. Results: Two hundred and nine rats were captured, comprising of 71 domestic and 138 wild rats. The overall positive rate was 9.6%(20/209). The positive rate in domestic rats was 2.8%(2/71), including one Rattus norvebicus and one Rattus flavipectus. The positive rate in wild rats was 13.0%(18/138), including 13 Bandicota indica, one Rattus losea, 2 Rattus confucianus and 2 Rattus fulvescens. The positive rate was significantly higher in wild rats than in domestic rats (P < 0.05). The Youxi region had the highest positive rate(14.9%,13/87), followed by Yong'an(13.6%, 3/22), and no positive rat was found in Qingliu. The positive rate in the male rats was 7.9%(9/114), and that in the females was 11.6%(11/95). The positive rate was highest in adult rats (10.4%,18/173), followed by young ones (6.3%,2/32). No positive rat was found in old rats. There was no significant difference in positive rate among different regions, between male and female rats, or among different ages (P > 0.05). The sequences of PCR products had a 100% homology. The BLAST results revealed the species to be Babesia microti. The phylogenetic tree showed that the sample sequence was the most homologous with Babesia microti from Zhejiang Province(GenBank Accession No: JQ609305). Conclusion: There occurs Babesia microti infection in rats in part areas of Fujian Province. The positive rate was higher in wild rats than in domestic rats.

The effect of temperature on the extrinsic incubation period and infection rate of dengue virus serotype 2 infection in Aedes albopictus.

Dengue fever is an acute mosquito-borne viral disease caused by dengue virus (DENV). Temperature may affect the efficiency of the mosquito vectors in spreading DENV. Aedes albopictus mosquitoes were infected orally with a DENV2 suspension and incubated at different temperatures. Subsequently, DENV2 antigen was collected from salivary gland and thorax-abdomen samples on different days postinfection and tested using an immunofluorescence assay to determine the extrinsic incubation period and infection rate. As the temperature increased, the extrinsic DENV2 incubation period in Ae. albopictus gradually shortened, and infection rates showed a tendency to initially increase, followed by a subsequent decrease.

Molecular epidemiology of hepatitis C virus among different groups of people in the province of Fujian, China.

Genotyping of hepatitis C virus (HCV) can provide valuable information for prognosis and treatment duration prediction. To explore the genetic diversity of HCV in Fujian Province, China, 112, 104 and 48 anti-HCV-positive serum samples were collected from volunteer blood donors, IDUs and patients, respectively, from Jan 2008 to Dec 2008 and were genotyped through sequence analysis, followed by phylogenetic analysis in the C/E1 and NS5B regions. Genotypes could be determined for 85.61 and 84.85 % of samples in the C/E1 and NS5B region, respectively. 6a was the most prevalent subtype, which accounted for 42.04 and 43.75 % in the C/E1 and NS5B region, respectively. Mixed infection and potential recombination were detected in this study. Kappa tests indicated that similar results were obtained by two genotyping methods targeting the C/E1 and NS5B regions. The differences in the main prevalent subtype between the three target groups suggest diversity of HCV prevalence in different populations.

Simulating potential outbreaks of Delta and Omicron variants based on contact-tracing data: A modelling study in Fujian Province, China.

Although studies have compared the relative severity of Omicron and Delta variants by assessing the relative risks, there are still gaps in the knowledge of the potential COVID-19 burden these variations may cause. And the contact patterns in Fujian Province, China, have not been described. We identified 8969 transmission pairs in Fujian, China, by analyzing a contact-tracing database that recorded a SARS-CoV-2 outbreak in September 2021. We estimated the waning vaccine effectiveness against Delta variant infection, contact patterns, and epidemiology distributions, then simulated potential outbreaks of Delta and Omicron variants using a multi-group mathematical model. For instance, in the contact setting without stringent lockdowns, we estimated that in a potential Omicron wave, only 4.7% of infections would occur in Fujian Province among individuals aged >60 years. In comparison, 58.75% of the death toll would occur in unvaccinated individuals aged >60 years. Compared with no strict lockdowns, combining school or factory closure alone reduced cumulative deaths of Delta and Omicron by 28.5% and 6.1%, respectively. In conclusion, this study validates the need for continuous mass immunization, especially among elderly aged over 60 years old. And it confirms that the effect of lockdowns alone in reducing infections or deaths is minimal. However, these measurements will still contribute to lowering peak daily incidence and delaying the epidemic, easing the healthcare system's burden.

Inactivated vaccine effectiveness against symptomatic COVID-19 in Fujian, China during the Omicron BA.2 outbreak.

Objective: More than 90% of the Chinese population have completed 2 doses of inactivated COVID-19 vaccines in Mainland China. However, after China government abandoned strict control measures, many breakthrough infections appeared, and vaccine effectiveness against Omicron BA.2 infection was uncertain. This study aims to investigate the real-world effectiveness of widely used inactivated vaccines during the wave of Omicron variants. Methods: Test-negative case-control study was conducted in this study to analyze the vaccine effectiveness against symptomatic disease caused by the Omicron variant (BA.2) in Fujian, China. Conditional logistic regression was selected to estimate the vaccine effectiveness. Results: The study found the vaccine effectiveness against symptomatic COVID-19 is 32.46% (95% CI, 8.08% to 50.37%) at 2 to 8 weeks, and 27.05% (95% CI, 1.23% to 46.12%) at 12 to 24 weeks after receiving booster doses of the inactivated vaccine. Notably, the 3-17 years group had higher vaccine effectiveness after 2 doses than the 18-64 years and over 65 years groups who received booster doses. Conclusion: Inactivated vaccines alone may not offer sufficient protection for all age groups before the summer of 2022. To enhance protection, other types of vaccines or bivalent vaccines should be considered.

Microbial community compositional analysis for series reactors treating high level antibiotic wastewater.

A full-scale biosystem consisting of two anaerobic reactors (HA and BF1) and four aerobic ones (BF2-BF4 and OD) in succession and receiving antibiotic-bearing (mainly streptomycin) wastewater was used for studying the impacts of antibiotics on microbial community structures. Significant decreases of streptomycin (from 3955 ± 1910 to 23.1 ± 4.7 µg L(-1)) and COD(Cr) were observed along the treatment process. Cloning results show that the anaerobic reactors (HA and BF1) were dominated with Deltaproteobacteria (51%) mainly affiliated with sulfate-reducing bacteria (SRB), while the aerobic BF2 receiving streptomycin of 408.6 ± 59.7 µg L(-1) was dominated with Betaproteobacteria (34%), Deltaproteobacteria (31%) and Bacteroidetes (14%). Gammaproteobacteria (15.9-22.4%), Betaproteobacteria (10.0-20.3%), and Bacteroidetes (4.5-29.7%) became the major bacterial groups in aerobic BF3-OD receiving streptomycin of ≤83 ± 13 µg L(-1). Archaea affiliated with Methanomethylovorans hollandica-like methylotroph was abundant in HA and BF1 (archaea/bacteria, 0.54-0.40; based on specific gene copy number), suggesting the coexistence of SRB and methanogens in degrading pollutants. Fungi were abundant (fungi/bacteria, 0.15; based on specific gene copy number) with the dominance of Ascomycota (clone ratio of Ascomycota/eukarya, 25.5%) in BF2, suggesting that fungi could be an important player in pollutant removal under high levels of antibiotics. This study demonstrates that under high antibiotic levels, wastewater treatment communities may maintain system stability through adjusting bacterial, archaeal, and eukaryal compositions.

Prevalence and phylogenetic analysis of Babesia parasites in reservoir host species in Fujian province, Southeast China.

Babesiosis is a tick-borne disease that mainly affects small mammals and has been reported in at least five provinces in China. However, the host range and geographical distribution of the parasite in Fujian province are unclear. Therefore, we investigated the prevalence and genetic characteristics of Babesia in Fujian province, Southeast China, between 2015 and 2020. Rodent blood samples were collected from 26 different surveillance sites across Fujian province. Genomic DNA was extracted to screen for Babesia infection using polymerase chain reaction based on 18S rRNA. DNA samples from 316 domestic goats, 85 water buffalo, 56 domestic dogs and 18 domestic pigs were examined. The prevalence of Babesia was statistically analysed using the Chi-square test or Fisher's exact test. Babesia infections were detected in 3.96% (43/1,087; 95%CI: 2.80%, 5.12%) of rodents and 1.26% (6/475; 95%CI: 0.26%, 2.26%) of other mammals. Multivariate logistic regression analysis revealed that irrigated cropland, shrubs and forests were risk factors for Babesia microti infections. The infection rates among domestic pigs, dogs and goats were 5.56%, 1.79% and 1.27%, respectively, with no infection found in water buffalo. The 18S rRNA gene sequencing revealed that rodents were infected with Babesia (sensu lato), whereas other mammals were infected with Babesia (sensu stricto). The geographical distribution and phylogenetic relationship of Babesia was determined in Southeast China. Mammals, particularly wild rodents, maybe the main natural hosts of Babesia in Fujian. Our findings provide a foundation for public health officials to develop prevention and control measures for Babesia.

The effects of vaccination on the disease severity and factors for viral clearance and hospitalization in Omicron-infected patients: A retrospective observational cohort study from recent regional outbreaks in China.

Object: This study attempted to explore the effects of vaccination on disease severity and the factors for viral clearance and hospitalization in omicron-infected patients. Methods: The clinical manifestations of 3,265 Omicron-infected patients (BA.2 lineage variant; the Omicron group) were compared with those of 226 Delta-infected patients (the Delta group). A Multi-class logistic regression model was employed to analyze the impacts of vaccination doses and intervals on disease severity; a logistic regression model to evaluate the risk factors for hospitalization; R 4.1.2 data analysis to investigate the factors for time for nucleic acid negativization (NAN). Results: Compared with the Delta group, the Omicron group reported a fast transmission, mild symptoms, and lower severity incidence, and a significant inverse correlation of vaccination dose with clinical severity (OR: 0.803, 95%CI: 0.742-0.868, p<0.001). Of the 7 or 5 categories of vaccination status, the risk of severity significantly decreased only at ≥21 days after three doses (OR: 0.618, 95% CI: 0.475-0.803, p<0.001; OR: 0.627, 95% CI: 0.482-0.815, p<0.001, respectively). The Omicron group also reported underlying illness as an independent factor for hospitalization, sore throat as a protective factor, and much shorter time for NAN [15 (12,19) vs. 16 (12,22), p<0.05]. NAN was associated positively with age, female gender, fever, cough, and disease severity, but negatively with vaccination doses. Conclusion: Booster vaccination should be advocated for COVID-19 pandemic-related control and prevention policies and adequate precautions should be taken for patients with underlying conditions.

Investigation of Brucellosis Caused by Raw Goat Milk - Fujian Province, China, April-June, 2019.

What is already known about this topic? Brucellosis is one of the most important zoonotic diseases in China. Goat milk and dairy products are essential pathways for foodborne transmission of brucellosis. Pasteurization can completely kill Brucellaspp. in milk, and milk-borne transmission is mainly related to unhealthy dietary hygiene habits and insufficient epidemic control among animals. What is added by this report? This epidemic is the first outbreak of brucellosis in Zhangping City, Fujian Province. A total of 6 confirmed cases were found, and the onset time was from April to June 2019. The investigation suggested that the transmission chain of the epidemic included a private butcher, an infected goat from the north, a dairy farmer, close contact spread, unsterilized goat milk, and consumers drinking raw goat milk. What are the implications for public health practices? For the non-endemic area of brucellosis, preventing the import of infected animals and enhancing the practitioner's and the public's awareness of disease prevention has important public health significance. It is necessary to strengthen the transregional quarantine of livestock, the food safety inspection and management, and the practitioners' and public's awareness of food safety.

Cell surface properties of five polycyclic aromatic compound-degrading yeast strains.

To investigate the effects of physiological properties on polycyclic aromatic compound (PAH) degradation, the surface tension and emulsification activities, and cell surface hydrophobicity of five PAH-degrading yeast isolates were compared to Saccharomyces cerevisiae from cultures grown with glucose, hexadecane, or naphthalene as carbon sources. The cell surface hydrophobicity values for the five yeast strains were significantly higher than for S. cerevisiae for all culture conditions, although these were highest with hexadecane and naphthalene. Strains with higher hydrophobicity showed higher rates of naphthalene and phenanthrene degradation, indicating that increased cell hydrophobicity might be an important strategy in PAH degradation for the five strains. Emulsification activities increased for all five yeast strains with naphthalene culturing, although no relationship existed between emulsification activity and PAH degradation rate. Surface tensions were not markedly reduced with naphthalene culturing.

Mutations of connexin 26 at position 75 and dominant deafness: essential role of arginine for the generation of functional gap-junctional channels.

Gap-junctional channels are large intercellular aqueous pores formed by head-to-head association of two gap-junctional hemichannels (connexin hexamers), one from each of the adjacent cells. The mechano-transduction of sound waves into electrical impulses occurs in the cochlea, which houses the organ of Corti. Hereditary deafness is frequent and mutations of connexin 26, the predominant connexin of the cochlea, are its most frequent cause. Mutations of R75 cause deafness and disrupt gap-junctional communication. Here, we determined the effects of substitutions of R75 with different residues (alanine, asparagine, aspartic acid, lysine, phenylalanine, tyrosine or tryptophan) on formation of gap-junctional channels and hemichannels. We show that connexin 26 R75 is essential for the formation of gap-junctional channels. Substitution of R75 with aromatic residues yields functional hemichannels that display altered voltage dependence, whereas substitution with other residues yields non-functional hemichannels. The expression of R75 mutants has a dominant negative effect on gap-junctional communication mediated by wild-type connexin 26, independently of the ability of the mutants to form functional gap-junctional hemichannels. Our results show that the arginine located at position 75 of connexin 26 is essential for function, and cannot be replaced by other residues.

Evaluation of performance and microbial community in a two-stage UASB reactor pretreating acrylic fiber manufacturing wastewater.

A two-stage UASB reactor was employed to pretreat acrylic fiber manufacturing wastewater. Mesophilic operation (35 ± 0.5°C) was performed with hydraulic retention time (HRT) varied between 28 and 40 h. Mixed liquor suspended solids (MLSS) in the reactor was maintained about 8000 mg/L. The results showed COD and sulfate removal could be kept at 51% and 75%, respectively, when the HRT was no less than 38 h. Sulfate reduction mainly occurred in the acidification-stage reactor while methane production mainly occurred in the methane-stage reactor. The size of granule formed in the acidification-stage reactor ranged between 1 and 5mm while the largest size of granule in the methane-stage reactor ranged from 0.5 to 2mm. Compared to microbial populations in the acidification-stage reactor, the microbial diversity in methane-stage reactor was more abundant. In the acidification-stage reactor, the Syntrophobacter sulfatireducens devoted to both sulfate reduction and acetate production.

[Application of purified recombinant outer membrane lipoprotein LipL32 in detecting antibodies among leptospirosis cases].

OBJECTIVE: To establish recombinant outer membrane lipoprotein LipL32-based antibody detection assays in identifying leptospirosis. METHODS: Recombinant leptospiral outer membrane protein LipL32 was obtained by genetic engineering method. This purified protein was used in the indirect and sandwich ELISA assays to test the antibodies in sera of human beings and rats, and the results were compared with those obtained by microscopy agglutination test (MAT) and imported ELISA kit. RESULTS: When the acute and convalescent phase specimens from 9 leptospiral patients were tested, the detected rates of three ELISAs were similar to the MAT. Among the 45 probable cases which MAT showed positive, 32 (71.11%) samples were positive by r32-I-ELISA, 36 (80.00%) by r32-S-ELISA, while 28.89% (13/45) samples were positive and 55.56% (25/45) were suspicious by D.A.I-ELISA. The specificity of r32-I-ELISA and r32-S-ELISA were 97.10% (67/69) for 69 specimens. 43 healthy specimens were negative by both r32-I-ELISA and r32-S-ELISA, 14 healthy specimens were negative by D.A.I-ELISA. Among 16 non-leptospirosis patients, two specimens were positive by r32-I-ELISA and r32-S-ELISA, D.A.I-ELISA and identified one positive specimen, while 12 specimens were suspicious by D.A.I-ELISA. For 10 syphilis specimens, data obtained through three ELISAs were in consistent with that by MAT. A sandwiched ELISA, using rLipL32 protein as the antigen was developed to detect rat sera. Considering MAT as standard test, the sensitivity and specificity were 86.75% (131/151), 99.19% (122/123) respectively with coincidence rate as 92.34% (253/274). CONCLUSION: The recombinant protein LipL32 had high immunoreactivity and could be used as an antigen for the detection of pathogenic leptospirosis. In summary, the novel sandwiched ELISA with rLipL32 showed similar sensitivity and specificity to that of MAT in the antibody detection of rat leptospirosis. It was suitable for large scales field sero-epidemiological studies.

[Expression of truncated 56 kDa antigen gene of Orientia tsutsugamushi in different vectors].

OBJECTIVE: To construct recombinant plasmids containing the truncated gene of the major surface antigen sta56 of Orientia tsutsugamushi (Ot.) Karp strain for expression antigen in E. coli so as to compare the expression efficiency in different systems. METHODS: From the recombinant plasmid TOPO-sta56 containing sta56 of Orientia tsutsugamushi Karp strain, several truncated genes of sta56 with different length were amplified and subcloned into the expression vectors pPROEX HTb and pET30a. These genes were expressed in E. coli DH5alpha and BL21(DE3) respectively when induced by IPTG. The expressed recombinant proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot. RESULTS: Six recombinant plasmids containing truncated sta56 genes of different length were constructed as follow: pHTbOt957, pHTbOt498, pHTbOt342 and pETOt957, pETOt498, pETOt342. The recombinant sta56 proteins were highly expressed as 6 x His fusion proteins in E. coli DH5alpha and BL21(DE3) respectively. The fusion proteins showed as different bands of different molecular weight respectively when analyzed with SDS-PAGE. Western blot demonstrated that the recombinant proteins were recognized by the positive serum of Ot. patients. CONCLUSION: The sta56 gene of Orientia tsutsugamushi Karp strain could be highly expressed in E. coli and its expression showed better efficiency in pET30a than in pPROEX HTb. The recombinant sta56 antigen with immunoreactivity could be used as diagnostic reagent for Ot. infection.