Long-term neutralizing antibody dynamics against SARS-CoV-2 in symptomatic and asymptomatic infections: a systematic review and meta-analysis

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.

Modelling the initial epidemic trends of COVID-19 in Italy, Spain, Germany, and France.

The Coronavirus Disease 2019 (COVID-19) has fast spread to over 200 countries and regions worldwide since its outbreak, while in March, Europe became the emerging epicentre. In this study, we aimed to model the epidemic trends and estimate the essential epidemic features of COVID-19 in Italy, Spain, Germany, and France at the initial stage. The numbers of daily confirmed cases and total confirmed cases were extracted from the Coronavirus disease (COVID-19) situation reports of WHO. We applied an extended Susceptible-Exposed-Infectious-Removed (SEIR) model to fit the epidemic trend and estimated corresponding epidemic features. The transmission rate estimates were 1.67 (95% credible interval (CrI), 1.64-1.71), 2.83 (2.72-2.85), 1.91 (1.84-1.98), and 1.89 (1.82-1.96) for Italy, Spain, Germany, and France, corresponding to the basic reproduction numbers (R0) 3.44 (3.35-3.54), 6.25 (5.97-6.55), 4.03 (3.84-4.23), and 4.00 (3.82-4.19), respectively. We found Spain had the lowest ascertainment rate of 0.22 (0.19-0.25), followed by France, Germany, and Italy of 0.45 (0.40-0.50), 0.46 (0.40-0.52), and 0.59 (0.55-0.64). The peaks of daily new confirmed cases would reach on April 16, April 5, April 21, and April 19 for Italy, Spain, Germany, and France if no action was taken by the authorities. Given the high transmissibility and high covertness of COVID-19, strict countermeasures, such as national lockdown and social distancing, were essential to be implemented to reduce the spread of the disease.

Therapeutic Effect of Acupoint Injection with Nucleotide Plus Conventional Western Medicine Treament for Moderate and Severe Chronic Obstructive Pulmonary Disease / 广州中医药大学学报

Objective To observe the therapeutic effect of acupoint injection with nucleotide plus conventional western medicine treatment for moderate and severe chronic obstructive pulmonary disease (COPD).Methods Sixty patients confirmed as moderate and severe COPD were evenly randomized into treatment group and control group.The treatment group was given conventional western medicine treatment and injection with nucleotide on bilateral Dingchuan points,and the control group was given conventional western medicine treatment alone.The treatment lasted for one year.The frequency of COPD acute onset and hospitalization times within one year were recorded.Meanwhile,the severity of dyspnea was evaluated with Medical Research Council (MRC) dyspnea scale scoring.Results (1)The frequency of COPD acute onset and hospitalization times within one year in the treatment group were lowered,and the differences were significant compared with those in the control group (P ＜ 0.05 or P ＜ 0.01).(2) After treatment,MRC dyspnea scale scores in the treatment group were improved (P ＜ 0.05 compared with those before treatment),but the improvement of the scores was insignificant in the control group(P ＞ 0.05).The intergroup comparison showed that the effect on improving MRC dyspnea scale scores in the treatment group was superior to that in the control group (P ＜ 0.05),indicating that the severity of dyspnea was much improved in the treatment group as compared with the control group.Conclusion Acupoint injection with nucleotide is effective on enhancing the therapeutic effect of conventional western medicine treatment for moderate and severe COPD.

Investigation of drawing region of interest in diffusion-weighted imaging between spinal tuberculosis and malignancy / 生物医学工程学杂志

This study was aimed to evaluate the effect of region of interest (ROI) on measurement of apparent diffusion coefficient (ADC) obtained in diffusion-weighted (DW) MR sequences between spinal tuberculosis and malignancy, selecting the more reasonable and effective measurement of ADC value. We collected the conventional MR sequences and diffusion-weighted imaging data of thirty-two patients with spinal tuberculosis or malignancy confirmed clinically and pathologically from August 2009 to June 2010. Using the conventional MRI as a guide, the signal intensity (SI) and ADC value were calculated by selecting single ROI and the same area multi-ROI within whole lesion at the largest slice of lesion respectively. Using ADC value defined by receiver operating characteristic (ROC) curve analysis as threshold, the sensitivity, specificity, and accuracy of ADC value for diagnosing spinal tuberculosis were compared. The results showed that the mean of ADC value at signal ROI was lower than that at the multi-ROI. There was no significant difference between the ADC value of single ROI and multi-ROI. The ADC values from spinal tuberculosis and spinal malignancy obtained in single ROI or multi-ROI showed significant differences. The sensitivity, specificity, and accuracy of ADC value for differentiating tuberculosis from neoplastic infiltration at signal ROI is lower than that at the multi-ROI. In conclusion, the ADC acquired multi-ROI can describe preferablywater molecular diffusion and is more useful in differentiating spinal tuberculosis from malignant bone marrow lesions.