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BackgroundThe kinetics of the neutralizing antibody response against SARS-CoV-2 is crucial for responding to the pandemic as well as developing vaccination strategies. We aimed to fit the antibody curves in symptomatic and asymptomatic individuals. MethodsWe systematically searched PubMed, Embase, Web of Science, and Europe PMC for articles published in English between Jan 1, 2020, and Oct 2, 2022. Studies evaluating neutralizing antibody from people who had a natural SARS-CoV-2 infection history were included. Study quality was assessed using a modified standardized scoring system. We fitted dynamic patterns of neutralizing antibody using a generalized additive model and a generalized additive mixed model. We also used linear regression model to conduct both univariate and multivariable analyses to explore the potential affecting factors on antibody levels. This study is registered with PROSPERO, CRD42022348636. Results7,343 studies were identified in the initial search, 50 were assessed for eligibility after removal of duplicates as well as inappropriate titles, abstracts and full-text review, and 48 studies (2,726 individuals, 5,670 samples) were included in the meta-analysis after quality assessment. The neutralization titer of people who infected with SARS-CoV-2 prototype strain peaked around 27 days (217.4, 95%CI: 187.0-252.9) but remained below the Omicron BA.5 protection threshold all the time after illness onset or confirmation. Furthermore, neither symptomatic infections nor asymptomatic infections could provide over 50% protection against Omicron BA.5 sub-lineage. It also showed that the clinical severity and the type of laboratory assays may significantly correlated with the level of neutralizing antibody. ConclusionsThis study provides a comprehensive mapping of the dynamic of neutralizing antibody against SARS-CoV-2 prototype strain induced by natural infection and compared the dynamic patterns between prototype and variant strains. It suggests that the protection probability provided by natural infection is limited. Therefore, timely vaccination is necessary for both previously infected symptomatic and asymptomatic individuals.
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BackgroundAn outbreak of COVID-19 caused by the SARS-CoV-2 Omicron BA.2 sublineage occurred in Shanghai, China from February to June 2022. The government organized multiple rounds of molecular test screenings for the entire population, providing a unique opportunity to capture the majority of subclinical infections and better characterize disease burden and the full spectrum of Omicron BA.2 clinical severity. MethodsUsing daily reports from the websites of the Shanghai Municipal Health Commission, we estimated the incidence of infections, severe/critical infections, and deaths to assess the disease burden. By adjusting for right censoring and Reverse Transcription-Polymerase Chain Reaction (RT{square}PCR) sensitivity, we provide estimates of clinical severity, including the infection fatality risk, symptomatic case fatality risk, and risk of developing severe/critical disease upon infection. FindingsFrom February 26 to June 30, 2022, the overall infection rate, severe/critical infection rate, and mortality rate were 2.74 (95% CI: 2.73-2.74) per 100 individuals, 6.34 (95% CI: 6.02-6.66) per 100,000 individuals and 2.42 (95% CI: 2.23-2.62) per 100,000 individuals, respectively. The severe/critical infection rate and mortality rate increased with age with the highest rates of 125.29 (95% CI: 117.05-133.44) per 100,000 and 57.17 (95% CI: 51.63-62.71) per 100,000 individuals, respectively, noted in individuals aged 80 years or older. The overall fatality risk and risk of developing severe/critical disease upon infection were 0.09% (95% CI: 0.08-0.10%) and 0.23% (95% CI: 0.20-0.25%), respectively. Having received at least one vaccine dose led to a 10-fold reduction in the risk of death for infected individuals aged 80 years or older. InterpretationUnder the repeated population-based screenings and strict intervention policies implemented in Shanghai, our results found a lower disease burden and mortality of the outbreak compared to other settings and countries, showing the impact of the successful outbreak containment in Shanghai. The estimated low clinical severity of this Omicron BA.2 epidemic in Shanghai highlight the key contribution of vaccination and availability of hospital beds to reduce the risk of death. FundingKey Program of the National Natural Science Foundation of China (82130093). Research in contextO_ST_ABSEvidence before this studyC_ST_ABSWe searched PubMed and Europe PMC for manuscripts published or posted on preprint servers after January 1, 2022 using the following query: ("SARS-CoV-2 Omicron") AND ("burden" OR "severity"). No studies that characterized the whole profile of disease burden and clinical severity during the Shanghai Omicron outbreak were found. One study estimated confirmed case fatality risk between different COVID-19 waves in Hong Kong; other outcomes, such as fatality risk and risk of developing severe/critical illness upon infection, were not estimated. One study based on 21 hospitals across the United States focused on Omicron-specific in-hospital mortality based on a limited sample of inpatients (565). In southern California, United States, a study recruited more than 200 thousand Omicron-infected individuals and estimated the 30-day risk of hospital admission, intensive care unit admission, mechanical ventilation, and death. None of these studies estimated infection and mortality rates or other indictors associated with disease burden. Overall, the disease burden and clinical severity of the Omicron BA.2 variant have not been fully characterized, especially in populations predominantly immunized with inactivated vaccines. Added value of this studyThe large-scale and multiround molecular test screenings conducted on the entire population during the Omicron BA.2 outbreak in Shanghai, leading to a high infection ascertainment ratio, provide a unique opportunity to capture the majority of subclinical infections. As such, our study provides a comprehensive assessment of both the disease burden and clinical severity of the SARS-CoV-2 Omicron BA.2 sublineage, which are especially lacking for populations predominantly immunized with inactivated vaccines. Implications of all the available evidenceWe estimated the disease burden and clinical severity of the Omicron BA.2 outbreak in Shanghai in February-June 2022. These estimates are key to properly interpreting field evidence and assessing the actual spread of Omicron in other settings. Our results also provide support for the importance of strategies to prevent overwhelming the health care system and increasing vaccine coverage to reduce mortality.
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BackgroundIn early March 2022, a major outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant spread rapidly throughout Shanghai, China. Here we aimed to provide a description of the epidemiological characteristics and spatiotemporal transmission dynamics of the Omicron outbreak under the population-based screening and lockdown policies implemented in Shanghai. MethodsWe extracted individual information on SARS-CoV-2 infections reported between January 1 and May 31, 2022, and on the timeline of the adopted non-pharmacological interventions. The epidemic was divided into three phases: i) sporadic infections (January 1-February 28), ii) local transmission (March 1-March 31), and iii) city-wide lockdown (April 1 to May 31). We described the epidemic spread during these three phases and the subdistrict-level spatiotemporal distribution of the infections. To evaluate the impact on the transmission of SARS-CoV-2 of the adopted targeted interventions in Phase 2 and city-wide lockdown in Phase 3, we estimated the dynamics of the net reproduction number (Rt). FindingsA surge in imported infections in Phase 1 triggered cryptic local transmission of the Omicron variant in early March, resulting in the largest coronavirus disease 2019 (COVID-19) outbreak in mainland China since the original wave. A total of 626,000 SARS-CoV-2 infections were reported in 99.5% (215/216) of the subdistricts of Shanghai. The spatial distribution of the infections was highly heterogeneous, with 40% of the subdistricts accounting for 80% of all infections. A clear trend from the city center towards adjacent suburban and rural areas was observed, with a progressive slowdown of the epidemic spread (from 544 to 325 meters/day) prior to the citywide lockdown. During Phase 2, Rt remained well above 1 despite the implementation of multiple targeted interventions. The citywide lockdown imposed on April 1 led to a marked decrease in transmission, bringing Rt below the epidemic threshold in the entire city on April 14 and ultimately leading to containment of the outbreak. InterpretationOur results highlight the risk of widespread outbreaks in mainland China, particularly under the heightened pressure of imported infections. The targeted interventions adopted in March 2022 were not capable of halting transmission, and the implementation of a strict, prolonged city-wide lockdown was needed to successfully contain the outbreak, highlighting the challenges for successfully containing Omicron outbreaks. FundingKey Program of the National Natural Science Foundation of China (82130093). Research in contextO_ST_ABSEvidence before this studyC_ST_ABSOn May 24, 2022, we searched PubMed and Europe PMC for papers published or posted on preprint servers after January 1, 2022, using the following query: ("SARS-CoV-2" OR "Omicron" OR "BA.2") AND ("epidemiology" OR "epidemiological" OR "transmission dynamics") AND ("Shanghai"). A total of 26 studies were identified; among them, two aimed to describe or project the spread of the 2022 Omicron outbreak in Shanghai. One preprint described the epidemiological and clinical characteristics of 376 pediatric SARS-CoV-2 infections in March 2022, and the other preprint projected the epidemic progress in Shanghai, without providing an analysis of field data. In sum, none of these studies provided a comprehensive description of the epidemiological characteristics and spatiotemporal transmission dynamics of the outbreak. Added value of this studyWe collected individual information on SARS-CoV-2 infection and the timeline of the public health response. Population-based screenings were repeatedly implemented during the outbreak, which allowed us to investigate the spatiotemporal spread of the Omicron BA.2 variant as well as the impact of the implemented interventions, all without enduring significant amounts of underreporting from surveillance systems, as experienced in other areas. This study provides the first comprehensive assessment of the Omicron outbreak in Shanghai, China. Implications of all the available evidenceThis descriptive study provides a comprehensive understanding of the epidemiological features and transmission dynamics of the Omicron outbreak in Shanghai, China. The empirical evidence from Shanghai, which was ultimately able to curtail the outbreak, provides invaluable information to policymakers on the impact of the containment strategies adopted by the Shanghai public health officials to prepare for potential outbreaks caused by Omicron or novel variants.
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The emergence of SARS-CoV-2 variants have raised concerns over the protective efficacy of the current generation of vaccines, and it remains unclear to what extent, if any, different variants impact the efficacy and effectiveness of various SARS-CoV-2 vaccines. We systematically searched for studies of SARS-CoV-2 vaccine efficacy and effectiveness, as well as neutralization data for variants, and used a previously published statistical model to predict vaccine efficacy against variants. Overall, we estimate the efficacy of mRNA-1273 and ChAdOx1 nCoV-19 against infection caused by the Delta variant to be 25-50% lower than that of prototype strains. The predicted efficacy against symptomatic illness of the mRNA vaccines BNT162b2 and mRNA-1273 are 95.1% (UI: 88.4-98.1%) and 80.8% (60.7-92.3%), respectively, which are higher than that of adenovirus-vector vaccines Ad26.COV2.S (44.8%, UI: 29.8-60.1%) and ChAdOx1 nCoV-19 (41.1%, 19.8-62.8%). Taken together, these results suggest that the development of more effective vaccine strategies against the Delta variant may be needed. Finally, the use of neutralizing antibody titers to predict efficacy against variants provides an additional tool for public health decision making, as new variants continue to emerge.
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ImportanceWhether herd immunity through mass vaccination is sufficient to curb SARS-CoV-2 transmission requires an understanding of the duration of vaccine-induced immunity, and the necessity and timing of booster doses. Objective: To evaluate immune persistence of two priming doses of CoronaVac, and immunogenicity and safety of a third dose in healthy adults [≥]60 years. Design, setting, and participants: We conducted a vaccine booster study built on a single-center, randomized, double-blind phase 1/2 trial of the two-dose schedule of CoronaVac among healthy adults[≥]60 years in Hebei, China. We examined neutralizing antibody titres six months or more after the second dose in all participants. We provided a third dose to 303 participants recruited in phase 2 trial to assess their immune responses. InterventionsTwo formulations (3 g, and 6 g) were used in phase 1 trial, and an additional formulation of 1.5 g was used in phase 2 trial. All participants were given two doses 28 days apart and followed up 6 months after the second dose. Participants in phase 2 received a third dose 8 months after the second dose. Main outcomes and measuresGeometric mean titres (GMT) of neutralizing antibodies to live SARS-CoV-2 and adverse events were assessed at multiple time points following vaccination. ResultsNeutralizing antibody titres dropped below the seropositive cutoff of 8 at 6 months after the primary vaccination in all vaccine groups in the phase 1/2 trial. A third dose given 8 months or more after the second dose significantly increased neutralizing antibody levels. In the 3 g group (the licensed formulation), GMT increased to 305 [95%CI 215.3-432.0] on day 7 following the third dose, an approximately 7-fold increase compared with the GMT 28 days after the second dose. All solicited adverse reactions reported within 28 days after a booster dose were of grade 1 or 2 severity. Conclusion and relevanceNeutralizing antibody titres declined substantially six months after two doses of CoronaVac among older adults. A booster dose rapidly induces robust immune responses. This evidence could help policymakers determine the necessity and the timing of a booster dose for older adults. Trial registrationClinicalTrials.gov (NCT04383574).
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BackgroundTo allow a return to a pre-COVID-19 lifestyle, virtually every country has initiated a vaccination program to mitigate severe disease burden and control transmission. However, it remains to be seen whether herd immunity will be within reach of these programs. MethodsWe developed a data-driven model of SARS-CoV-2 transmission for China, a population with low prior immunity from natural infection. The model is calibrated considering COVID-19 natural history and the estimated transmissibility of the Delta variant. Three vaccination programs are tested, including the one currently enacted in China and model-based estimates of the herd immunity level are provided. ResultsWe found that it is unlike to reach herd immunity for the Delta variant given the relatively low efficacy of the vaccines used in China throughout 2021, the exclusion of underage individuals from the targeted population, and the lack of prior natural immunity. We estimate that, assuming a vaccine efficacy of 90% against the infection, vaccine-induced herd immunity would require a coverage of 93% or higher of the Chinese population. However, even when vaccine-induced herd immunity is not reached, we estimated that vaccination programs can reduce SARS-CoV-2 infections by 53-58% in case of an epidemic starts to unfold in the fall of 2021. ConclusionsEfforts should be taken to increase populations confidence and willingness to be vaccinated and to guarantee highly efficacious vaccines for a wider age range.
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BackgroundImmunity after SARS-CoV-2 infection or vaccination has been threatened by recently emerged SARS-CoV-2 variants. A systematic summary of the landscape of neutralizing antibodies against emerging variants is needed. MethodsWe systematically searched PubMed, Embase, Web of Science, and 3 pre-print servers for studies that evaluated neutralizing antibodies titers induced by previous infection or vaccination against SARS-CoV-2 variants and comprehensively collected individual data. We calculated lineage-specific GMTs across different study participants and types of neutralization assays. FindingsWe identified 56 studies, including 2,483 individuals and 8,590 neutralization tests, meeting the eligibility criteria. Compared with lineage B, we estimate a 1.5-fold (95% CI: 1.0-2.2) reduction in neutralization against the B.1.1.7, 8.7-fold (95% CI: 6.5-11.7) reduction against B.1.351 and 5.0-fold (95% CI: 4.0-6.2) reduction against P.1. The estimated neutralization reductions for B.1.351 compared to lineage B were 240.2-fold (95% CI: 124.0-465.6) reduction for non-replicating vector platform, 4.6-fold (95% CI: 4.0-5.2) reduction for RNA platform, and 1.6-fold (95% CI: 1.2-2.1) reduction for protein subunit platform. The neutralizing antibodies induced by administration of inactivated vaccines and mRNA vaccines against lineage P.1 were also remarkably reduced by an average of 5.9-fold (95% CI: 3.7-9.3) and 1.5-fold (95% CI: 1.2-1.9). InterpretationOur findings indicate that the antibody response established by natural infection or vaccination might be able to effectively neutralize B.1.1.7, but neutralizing titers against B.1.351 and P.1 suffered large reductions. Standardized protocols for neutralization assays, as well as updating immune-based prevention and treatment, are needed. FundingChinese National Science Fund for Distinguished Young Scholars Research in contextO_ST_ABSEvidence before this studyC_ST_ABSSeveral newly emerged SARS-CoV-2 variants have raised significant concerns globally, and there is concern that SARS-CoV-2 variants can evade immune responses that are based on the prototype strain. It is not known to what extent do emerging SARS-CoV-2 variants escape the immune response induced by previous infection or vaccination. However, existing studies of neutralizing potency against SARS-CoV-2 variants are based on limited numbers of samples and lack comparability between different laboratory methods. Furthermore, there are no studies providing whole picture of neutralizing antibodies induced by prior infections or vaccination against emerging variants. Therefore, we systematically reviewed and quantitively synthesized evidence on the degree to which antibodies from previous SARS-CoV-2 infection or vaccination effectively neutralize variants. Added value of this studyIn this study, 56 studies, including 2,483 individuals and 8,590 neutralization tests, were identified. Antibodies from natural infection or vaccination are likely to effectively neutralize B.1.1.7, but neutralizing titers against B.1.351 and P.1 suffered large reductions. Lineage B.1.351 escaped natural-infection-mediated neutralization the most, with GMT of 79.2 (95% CI: 68.5-91.6), while neutralizing antibody titers against the B.1.1.7 variant were largely preserved (254.6, 95% CI: 214.1-302.8). Compared with lineage B, we estimate a 1.5-fold (95% CI: 1.0-2.2) reduction in neutralization against the B.1.1.7, 8.7-fold (95% CI: 6.5-11.7) reduction against B.1.351 and 5.0-fold (95% CI: 4.0-6.2) reduction against P.1. The neutralizing antibody response after vaccinating with non-replicating vector vaccines against lineage B.1.351 was worse than responses elicited by vaccines on other platforms, with levels lower than that of individuals who were previously infected. The neutralizing antibodies induced by administration of inactivated vaccines and mRNA vaccines against lineage P.1 were also remarkably reduced by an average of 5.9-fold (95% CI: 3.7-9.3) and 1.5-fold (95% CI: 1.2-1.9). Implications of all the available evidenceOur findings indicate that antibodies from natural infection of the parent lineage of SARS-CoV-2 or vaccination may be less able to neutralize some emerging variants, and antibody-based therapies may need to be updated. Furthermore, standardized protocols for neutralizing antibody testing against SARS-CoV-2 are needed to reduce lab-to-lab variations, thus facilitating comparability and interpretability across studies.
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AbstractCOVID-19 vaccination is being conducted in over 190 countries/regions to control SARS-CoV-2 transmission and return to a pre-pandemic lifestyle. However, understanding when non-pharmaceutical interventions (NPIs) can be lifted as immunity builds up remain a key question for policy makers. To address it, we built a data-driven model of SARS-CoV-2 transmission for China. We estimated that to prevent the escalation of local outbreaks to widespread epidemics, stringent NPIs need to remain in place at least one year after the start of vaccination. Should NPIs alone be capable to keep the reproduction number (Rt) around 1.3, the synergetic effect of NPIs and vaccination could reduce up to 99% of COVID-19 burden and bring Rt below the epidemic threshold in about 9 months. Maintaining strict NPIs throughout 2021 is of paramount importance to reduce COVID-19 burden while vaccines are distributed to the population, especially in large populations with little natural immunity.
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BackgroundA rapidly increasing number of serological surveys for anti-SARS-CoV-2 antibodies have been reported worldwide. A synthesis of this large corpus of data is needed. PurposeTo evaluate the quality of serological studies and provide a global picture of seroprevalence across demographic and occupational groups, and to provide guidance for conducting better serosurveys. Data sourcesWe searched PubMed, Embase, Web of Science, and 4 pre-print servers for English-language papers published from December 1, 2019 to September 25, 2020. Study selectionSerological studies evaluating SARS-CoV-2 seroprevalence in humans. Data extractionTwo investigators independently extracted data from studies. Data SynthesisMost of 230 serological studies, representing tests in >1,400,000 individuals, identified were of low quality based on a standardized study quality scale. In the 51 studies of higher quality, high-risk healthcare workers had higher seroprevalence of 17.1% (95% CI: 9.9-24.4%), compared to low-risk healthcare workers and general population of 5.4% (0.7-10.1%) and 5.3% (4.2-6.4%). Seroprevalence varied hugely across WHO regions, with lowest seroprevalence of general population in Western Pacific region (1.7%, 0.0-5.0%). Generally, the young (<20 years) and the old ([≥]65 years) were less likely to be seropositive compared to middle-aged (20-64 years) populations. Seroprevalence correlated with clinical COVID-19 reports, with pooled average of 7.7 (range: 2.0 to 23.1) serologically-detected-infections per confirmed COVID-19 case. LimitationsSome heterogeneity cannot be well explained quantitatively. ConclusionsThe overall quality of seroprevalence studies examined was low. The relatively low seroprevalence among general populations suggest that in most settings, antibody-mediated herd immunity is far from being reached. Given the relatively narrow range of estimates of the ratio of serologically-detected infections to confirmed cases across different locales, reported case counts may help provide insights into the true proportion of the population infected. Primary Funding sourceNational Science Fund for Distinguished Young Scholars (PROSPERO: CRD42020198253).
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The pandemic of novel coronavirus disease 2019 (COVID-19) began in Wuhan, China, where a first wave of intense community transmission was cut short by interventions. Using multiple data source, we estimated the disease burden and clinical severity of COVID-19 by age in Wuhan from December 1, 2019 to March 31, 2020. We adjusted estimates for sensitivity of laboratory assays and accounted for prospective community screenings and healthcare seeking behaviors. Rates of symptomatic cases, medical consultations, hospitalizations and deaths were estimated at 796 (95%CI: 703-977), 489 (472-509), 370 (358-384), and 36.2 (35.0-37.3) per 100,000 persons, respectively. The COVID-19 outbreak in Wuhan had higher burden than the 2009 influenza pandemic or seasonal influenza, and that clinical severity was similar to that of the 1918 influenza pandemic. Our comparison puts the COVID-19 pandemic into context and could be helpful to guide intervention strategies and preparedness for the potential resurgence of COVID-19.
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We conducted two surveys to evaluate the health-seeking behaviors of individuals with acute respiratory infections (ARI) during the COVID-19 outbreak in Wuhan, China. Among 351 participants reporting ARI (10.3%, 351/3,411), 36.5% sought medical assistance. Children were more likely to seek medical assistance than other age groups (66.1% vs. 28.0%-35.1%).
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ObjectiveThe outbreak of novel coronavirus disease 2019 (COVID-19) imposed a substantial health burden in mainland China and remains a global epidemic threat. Our objectives are to assess the case fatality risk (CFR) among COVID-19 patients detected in mainland China, stratified by clinical category and age group. MethodsWe collected individual information on laboratory-confirmed COVID-19 cases from publicly available official sources from December 29, 2019 to February 23, 2020. We explored the risk factors associated with mortality. We used methods accounting for right-censoring and survival analyses to estimate the CFR among detected cases. ResultsOf 12,863 cases reported outside Hubei, we obtained individual records for 9,651 cases, including 62 deaths and 1,449 discharged cases. The deceased were significantly older than discharged cases (median age: 77 vs 39 years, p<0.001). 58% (36/62) were male. Older age (OR 1.18 per year; 95%CI: 1.14 to 1.22), being male (OR 2.02; 95%CI: 1.02 to 4.03), and being treated in less developed economic regions (e.g., West and Northeast vs. East, OR 3.93; 95%CI: 1.74 to 8.85) were mortality risk factors. The estimated CFR was 0.89-1.24% among all cases. The fatality risk among critical patients was 2-fold higher than that among severe and critical patients, and 24-fold higher than that among moderate, severe and critical patients. ConclusionsOur estimates of CFR based on laboratory-confirmed cases ascertained outside of Hubei suggest that COVID-19 is not as severe as severe acute respiratory syndrome and Middle East respiratory syndrome, but more similar to the mortality risk of 2009 H1N1 influenza pandemic in hospitalized patients. The fatality risk of COVID-19 is higher in males and increases with age. Our study improves the severity assessment of the ongoing epidemic and can inform the COVID-19 outbreak response in China and beyond.
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BackgroundThe COVID-19 epidemic originated in Wuhan City of Hubei Province in December 2019 and has spread throughout China. Understanding the fast evolving epidemiology and transmission dynamics of the outbreak beyond Hubei would provide timely information to guide intervention policy. MethodsWe collected individual information on 8,579 laboratory-confirmed cases from official publically sources reported outside Hubei in mainland China, as of February 17, 2020. We estimated the temporal variation of the demographic characteristics of cases and key time-to-event intervals. We used a Bayesian approach to estimate the dynamics of the net reproduction number (Rt) at the provincial level. ResultsThe median age of the cases was 44 years, with an increasing of cases in younger age groups and the elderly as the epidemic progressed. The delay from symptom onset to hospital admission decreased from 4.4 days (95%CI: 0.0-14.0) until January 27 to 2.6 days (0.0-9.0) from January 28 to February 17. The mean incubation period was estimated at 5.2 days (1.8-12.4) and the mean serial interval at 5.1 days (1.3-11.6). The epidemic dynamics in provinces outside Hubei was highly variable, but consistently included a mix of case importations and local transmission. We estimate that the epidemic was self-sustained for less than three weeks with Rt reaching peaks between 1.40 (1.04-1.85) in Shenzhen City of Guangdong Province and 2.17 (1.69-2.76) in Shandong Province. In all the analyzed locations (n=10) Rt was estimated to be below the epidemic threshold since the end of January. ConclusionOur findings suggest that the strict containment measures and movement restrictions in place may contribute to the interruption of local COVID-19 transmission outside Hubei Province. The shorter serial interval estimated here implies that transmissibility is not as high as initial estimates suggested.
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Objective To analyze the characteristics of lethal peritoneal dialysis related peritonitis and to define the risk factors.Methods All patients who developed PD related peritonitis between Jan.1999 and May 2015 in PUMCH were included.Clinical profiles were collected.Patients were divided into mortality group(n=16) and non-mortality group(n=182) according to whether peritonitis causing mortality.Baseline clinical profiles were compared between two groups.Cox regression analysis was used to define the risk factors for mortality.Results White blood cells [(10.2±6.3)×109/L vs (5.8±1.8)×109/L,P<0.05] increased,but serum albumin[(25.2±8.5)g/L vs (34.0±6.3)g/L,P<0.05] and potassium concentration [(3.5±0.9)mmol/L vs (4.5±1.0)mmol/L,P<0.05] decreased at the time of lethal peritonitis bacteria and fungus cultures were positive in half of the patients as bacteria (31.2%),fungus (12.5%)and mycobacterium tuberculosis (6.25%).Multiple cox regression analysis identified cardiovascular disease as the independent risk factor for peritonitis related mortality (HR 9.318,95% CI 1.875~46.305,P<0.01).Conclusions Peritonitis of patients with cardiovascular disease may cause death.
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Objective To explore the relationship between lung function and bone mineral density (BMD) in nonsmoking women. Method The healthy women who came to our hospital for physical examination from June 2013 to March 2014 were chosen. Totally 508 cases, average age 49.33±8.66 years , were included through the questionnaire and further examination. The lumbar BMD was measured with dual energy X-ray absorption, the subjects were divided into normal bone mass group, osteopenia group, and osteoporosis group according to the diagnostic criteria of WHO. Through questionnaires, the human body composition analyzer, pulmonary function test apparatus were used to acquire their general information, body mass index (BMI) and pulmonary ventilation function. The data were compared by analysis of variance, Pearson correlation analysis and multiple linear stepwise regression analysis were applied to explore the relationship among the pulmonary ventilation function and bone mineral density of lumbar spine and lumbar bone area (BA). Result BMI, forced vital capacity rate of one second (FEV1/FVC) were not significantly different among the three groups (F values were 0.192, 0.296;All P>0.05);the other indicators of pulmonary function including forced vital capacity (FVC),FVC percent predicted (FVC%), forced expiratory volume in first second(FEV1), FEV1 percent predicted(FEV1%),peak expiratory flow rate(PEF)decreased markedly in osteoporosis group compared with normal group and osteopenia group (F=15.313, 5.508, 18.890, 5.440, 6.763;all P<0.05). The lumbar spine BMD and lumbar BA declined significantly in osteoporosis group and osteopenia group comparing with normal group(F=169.053, 205.660, 224.567, 201.086, 276.927, 3.550;all P<0.05). Pearson correlation analysis showed that FVC, FVC%, FEV1, FEV1%, PEF were negatively correlated with age (all P<0.01);FVC, FVC%were negatively correlated with BMI (all P<0.05) , FEV1/FVC was positively correlated with BMI P<0.05);FVC was positively correlated with lumbar BMD and lumbar BA (P<0.01). FEV1 were positively correlated with lumbar BMD and lumbar BA(all P<0.01). Multiple regression showed that age, BMI, and lumbar BA were correlated with FVC, FVC%, FEV1, FEV1/FVC(All P<0.01). Conclusion In healthy nonsmoking women, age, BMI, and lumbar BA are the main influencing factors of pulmonary function;except for FEV1/FVC, the other indicators of pulmonary function decreased markedly in osteoporosis group.
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Objective To investigate the relationship of pulmonary function and metabolic indexes in overweight as well as obesity people.Methods Three hundred and five health examination adults were selected as our subjects.The basic parameters,metabolic indexes and pulmonary function were measured.Of which,pulmonary function indexes include forced vital capacity (FVC),forced expiratory volume in one(FEV1),peak expiratory flow(PEF),the ratio of the forced expiratory volume in the first one second to the forced vital capacity (FEV1/FVC),the ratio of the forced expiratory volume in the first one second to the vital capacity(FEV1/VC),maximal expiratory flow after 50％ of the FVC (MEF50),maximal expiratory flow after 25％ of the FVC (MEF25),and each index value of lung function was expressed the ratio of the measured value/the predictive value.Metabolic indexes include triglycerides (TG),total cholesterol (TC),low-density lipoprotein cholesterol (LDL-C),fasting plasma glucose (FPG)),C-reactive protein (CRP),high-sensitivity C-reactive (hs-CRP),superoxide dismutase(SOD),systoloc blood pressure (SBP) and diastolic blood pressure (DBP).Statistical analysis methods include one-way analysis of variance and Spearman correlation analysis.Results The levels of FVC,FEV1,FEV1/FVC in overweight and the obesity group were (85.74 ± 13.94)％ and (82.85±13.34)％,(84.52 ± 14.62)％ and (82.74 ± 14.18)％,(103.40 ± 13.05)％ and (103.17 ±8.99)％respectively,lower than that of normal weight group [(95.79 ± 26.83) ％,(92.65 ± 26.93) ％,(99.98± 11.88) ％,all P values less than 0.05)].Compared with the normal weight group,the levels of TG,SBP,FPG in overweight group and the obesity group were significantly increased.The levels of LDL-C,DBP,hs-CRP in obesity were (5.05 ± 0.83) rmtmol/L,(86.64 ± 10.49) mmHg,(3.74 ± 5.51) mg/L respectively,higher than that of normal group [(3.08 ±0.96) mmol/L,(77.69 ± 13.20) mmHg,(2.33 ±4.67) mg/L,P ＜0.05)].SOD activities in overweight and obesity group were (140.82 ± 13.16),(144.89 ± 13.82) U/L respectively,significantly lower than that of normal weight group[(148.64 ± 14.94) U/L,P ＜0.05)).The levels of SBP,DBP,hs-CRP in the over weight group were (127.77 ± 19.07) mmHg,(80.87 ± 12.21) mmHg,(2.31± 3.73) mg/L),higher than that of obesity group.Among metabolic indices,TG,SBP,DBP,FBG,CRP,hs-CRP and SOD were related with FVC (r =-0.129,-0.129,-0.136,-0.180,-0.220,-0.217 respectively,P ＜ 0.05 or P ＜ 0.01).There was negatively correlated relationship between SBP,FBG,CRP,hs-CRP and FEV1 (r =-0.128,-0.127,-0.148,-0.198 respectively,P ＜0.05 or P ＜0.01),So were SBP,CRP,hs-CRP and PEF (r =-0.137,-0.117,-0.133 respectively,P ＜ 0.05).Negatively correlated relationship between hsCRP,SBP and MEF50 were seen (r =-0.126,-0.124,P ＜ 0.05).Meanwhile there was negatively correlated relationship between SOD and FVC,FEV1/FEV,PEF,MEF50 (r =0.149,0.094,0.119,0.141,0.129respectively,P ＜ 0.05 or P ＜ 0.01).Conclusion Impaired pulmonary function and metabolic disorders were showed in the overweight and obesity people.Metabolic indexes were related with pulmonary function.
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BACKGROUND: Strontium-doped calcium polyphosphate (SCPP), as a new repairing material, has been demonstrated to have favorable biocompatibility and biodegradability and some effects on promoting self-angiogenesis. However, the mechanism remains still unknown. OBJECTIVE: Endothelial cells were cultured with SCPP scaffolds in vitro, as well as the cell proliferation and angiogenic factor matrix metalloproteinase-2 (MMP-2) secretion were observed. DESIGN,TIME AND SETTING: A contrast study was performed at the Laboratory of Tissue Engineering of Sichuan University from September 2008 to April 2009. MATERIALS: A series of calcium polyphosphate (CPP) respectively containing 1 %, 2%, 5%, 8%, and 10% Sr~(2+) were prepared.METHODS: ① Materials were plated on 24-well culture plate,and endothelial cell suspension (300 μL) were seeded on 24-well culture plate at the concentration of 3×10~7/L and cultured with 200 uL RPMI1640 culture media. Endothelial cell proliferation was observed using MTT method at days 1,3,5, and 7 after culture. ② CPP and 8% SCPP were plated on 24-well culture plate, and endothelial cell suspension (300 uL) was then incubated in 24-well culture plate at the concentration of 1x10~8/L and cultured with 600 uL RPMI1640 culture media. The morphology of endothelial cells was observed by scanning electron microscopy (SEM) at day 5 after culture.③ Endothelial cells were co-cultured with SCPP of various Sr~(2+) contents for 5 days. After confluence, cells were centrifuged to obtain supernatant. Angiogenic factor MMP-2 secretion was evaluated by ELISA assay.MAIN OUTCOME MEASURES: The proliferation and morphology of endothelial cells on SCPP and CPP were observed. The amount of endothelial cells-derived MMP-2 protein secretion was detected. RESULTS: MTT method demonstrated that the proliferation of endothelial cells on the 8% SCPP scaffold showed a higher level compared to CPP, and other SCPP groups. Scanning electron microscope results suggested that endothelial cells on 8% SCPP had a better growth status and biological activity. ELISA results indicated that angiogenic factor MMP-2 expression on the SCPP was promoted compared with that of CPP, and 8% SCPP showed the highest expression (P < 0.05). CONCLUSION: SCPP has good compatibility with endothelial cells,promoting angiogenesis and enhancing the angiogenic factor MMP-2 expression.
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OBJECTIVE To study the aminoglycosides modifying enzyme genes and intⅠ gene in Stenotrophomonas maltophilia in Chinese Armed Police Forces General Hospital.METHODS The samples of 27 multi-resistant S.maltophilia were collected from inpatiens from Jan 2006 to Oct 2007 in this Hospital.The sensitivity of the isolates to 14 antibacterial agents was determined using a broth induction method.The aminoglycosides modifying enzyme genes and intⅠ 1 gene were detected by PCR.RESULTS The multi-drug resistance of S.maltophilia was a serious problem.In 27 strains of S.maltophilia,the positive ant(2″)-Ⅰ were in 5 strains(18.5%),aac(3)-Ⅱ in 3 strains(11.1%)and aac(6')-Ⅱ in 1 strain(3.7%).The positive intⅠ gene was found in 11 strains(29.6%).CONCLUSIONS Multi-resistant S.maltophilia resistant to aminoglycosides mainly due to the presence of aminoglycoside modifying enzymes ant(2″)-Ⅰ,aac(3)-Ⅱ and aac(6')-Ⅱ.The aminoglycoside modifying enzymes ant(3″)-Ⅰ and aac(6)-ⅠZ were not detected carrying IntⅠ would be the reason of S.maltophilia resistant to aminoglycosides.
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OBJECTIVE To investigate the distribution and characterization of the classes Ⅰ,Ⅱ and Ⅲ integrons on Stenotrophomonas maltophilia and clarify their influence on the bacterial drug-resistance.METHODS A multi-PCR assay using specific primers of int1,int2 and int3 was constructed to screen classes Ⅰ,Ⅱ and Ⅲ integrons.RESULTS Class Ⅰ integron was detected in 13.4% of clinical isolates,3 isolates harbored among class Ⅱ integrons. There was not been reported in abroad.CONCLUSIONS Classes Ⅰ and Ⅱ integrons could play an important role in causing the antibiotic multidrug resistance.
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liver fire exuberant syndrome. Conclusion Hs-CRP and IMT can be used as important indexes of TCM syndrome differentiation of MS.
