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2.
Front Med ; 2022 Feb 28.
Article in English | MEDLINE | ID: covidwho-1712327

ABSTRACT

The record speed at which Chinese scientists identified severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) and shared its genomic sequence with the world, has greatly facilitated the development of coronavirus disease (COVID-19) diagnostics, drugs, and vaccines. It is unprecedented in pandemic control history to develop a dozen successful vaccines in the first year and to immunize over half of the global population in the second year, due to the efforts of the scientific community, biopharmaceutical industry, and regulatory agencies worldwide. The challenges are both great and multidimensional due to the rapid emergence of virus variants and waning of vaccine immunity. Vaccination strategies need to adapt to these challenges to keep population immunity above the herd immunity threshold, by increasing vaccine coverage, especially for older adults and young people, and providing timely booster doses with homologous or heterologous vaccine boosts. Further research should be undertaken to develop more effective vaccines against SARS-CoV-2 variants and to understand the best prime-boost vaccine combinations and immunization strategies to provide sufficient and sustainable immune protection against COVID-19.

3.
Pathogens ; 11(2)2022 Jan 27.
Article in English | MEDLINE | ID: covidwho-1677702

ABSTRACT

Assessing the duration of neutralizing antibodies (nAbs) following SARS-CoV-2 infection or vaccination is critical to evaluate the protective immunity and formulate public health strategies. In this study, SARS-CoV-2 Ab ELISA (enzyme-linked immunosorbent assay), chemiluminescent microparticle immunoassay (CMIA), as well as pseudovirus neutralization test (PVNT) were performed in two cohorts, convalescent patients (CP) from coronavirus disease 2019 (COVID-19) and BBIBP-CorV vaccinated population. It was found that nAbs and binding antibodies emerged at 14 days post the 1st dose of vaccination, reached peaks at 28 days after 2nd dose vaccination and then gradually declined over time. CP-6M (convalescent patients up to 6 months) from COVID-19 presented stronger nAbs or binding antibodies responses than vaccinees 90 days or 180 days after 2nd dose vaccination. CMIA or SARS-CoV-2 Ab ELISA correlated well with PVNT with high consistency in the two cohorts. It shown that nAbs and binding antibodies can keep 6 months both in CP and vaccinees. Most importantly, our data show the application of using CMIA and SARS-CoV-2 Ab ELISA as rapid screening tests for nAb titer and could be used as alternative strategies for quickly evaluating SARS-CoV-2 nAbs responses in vaccine research.

4.
BMC Public Health ; 21(1): 605, 2021 03 29.
Article in English | MEDLINE | ID: covidwho-1158204

ABSTRACT

BACKGROUND: The COVID-19 pandemic is complex and is developing in different ways according to the country involved. METHODS: To identify the key parameters or processes that have the greatest effects on the pandemic and reveal the different progressions of epidemics in different countries, we quantified enhanced control measures and the dynamics of the production and provision of medical resources. We then nested these within a COVID-19 epidemic transmission model, which is parameterized by multi-source data. We obtained rate functions related to the intensity of mitigation measures, the effective reproduction numbers and the timings and durations of runs on medical resources, given differing control measures implemented in various countries. RESULTS: Increased detection rates may induce runs on medical resources and prolong their durations, depending on resource availability. Nevertheless, improving the detection rate can effectively and rapidly reduce the mortality rate, even after runs on medical resources. Combinations of multiple prevention and control strategies and timely improvement of abilities to supplement medical resources are key to effective control of the COVID-19 epidemic. A 50% reduction in comprehensive control measures would have led to the cumulative numbers of confirmed cases and deaths exceeding 590,000 and 60,000, respectively, by 27 March 2020 in mainland China. CONCLUSIONS: Multiple data sources and cross validation of a COVID-19 epidemic model, coupled with a medical resource logistic model, revealed the key factors that affect epidemic progressions and their outbreak patterns in different countries. These key factors are the type of emergency medical response to avoid runs on medical resources, especially improved detection rates, the ability to promote public health measures, and the synergistic effects of combinations of multiple prevention and control strategies. The proposed model can assist health authorities to predict when they will be most in need of hospital beds and equipment such as ventilators, personal protection equipment, drugs, and staff.


Subject(s)
COVID-19/therapy , Delivery of Health Care/organization & administration , Disease Outbreaks/prevention & control , Health Resources/statistics & numerical data , Pandemics , China/epidemiology , Delivery of Health Care/statistics & numerical data , Humans , Models, Theoretical , SARS-CoV-2 , Time Factors
6.
Infect Dis Model ; 5: 233-234, 2020.
Article in English | MEDLINE | ID: covidwho-831324
7.
Infect Dis Model ; 5: 848-854, 2020.
Article in English | MEDLINE | ID: covidwho-813617

ABSTRACT

The pandemic of the coronavirus disease (COVID-19) poses a huge challenge all countries, since no one is well prepared for it. To be better prepared for future pandemics, we evaluated association between the internet search data with reported COVID-19 cases to verify whether it could become an early indicator for emerging epidemic. After the keyword filtering and Index composition, we found that there were close correlations between Composite Index and suspected cases for COVID-19 (r = 0.921, P < 0.05). The Search Index was applied for the Autoregressive Integrated Moving Average with Exogenous Variables (ARIMAX) model to quantify the relationship. Compared with the model based on surveillance data only, the ARIMAX model had smaller Akaike Information Criterion (AIC = 403.51) and the most accurate predictive values. Overall, the Internet search data could serve as a convenient indicator for predicting the epidemic and to monitor its trends.

8.
Infect Dis Model ; 5: 282-292, 2020.
Article in English | MEDLINE | ID: covidwho-30935

ABSTRACT

Based on the official data modeling, this paper studies the transmission process of the Corona Virus Disease 2019 (COVID-19). The error between the model and the official data curve is quite small. At the same time, it realized forward prediction and backward inference of the epidemic situation, and the relevant analysis help relevant countries to make decisions.

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