ABSTRACT
We wished to understand the dynamic changes in production of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibodies in sera collected from coronavirus disease 19 (COVID-19) patients. Fifty-eight serum samples from 33 patients confirmed to have COVID-19 in Gansu Province, China, were tested for three types of SARS-CoV-2-specific antibodies: immunoglobulin (Ig) M, IgG, and total antibodies. The positive rate of IgM, IgG and total antibodies increased gradually with COVID-19 progression. Within the first 3 days, the positive rate of detection of SARS-CoV-2-specific antibody using the three kits was 13.6%-31.8%. whereas, within 4-7 days, it was 36.4%-45.5%, within 8-14 days it was 55.6%-77.8%, and after 15 days, it was 100%. In addition, the three kits were used to measure antibodies from serum samples collected from healthy people, and the specificity was 99%-100%. Statistical analyses indicated no significant difference among the results of the three kits (P > 0.05 for all). In summary, the three SARS-CoV-2 antibody-detection kits had good sensitivity and specificity for detection of antibodies against SARS-CoV-2, and could aid the clinical diagnosis of COVID-19. The dynamic characteristics of production of SARS-CoV-2- specific antibodies could provide important scientific bases for epidemiologic investigations.
ABSTRACT
Background: The global outbreak of COVID-19 has caused worrying concern amongst the public and health authorities. The first and foremost problem that many countries face is a shortage of medical resources. The experience of Wuhan, China, in fighting against COVID-19 provides a model for other countries to learn from. Methods: We formulated a piecewise smooth model to describe the limitation of hospital beds, based on the transmission progression of COVID-19, and the strengthening prevention and control strategies implemented in Wuhan, China. We used data of the cumulative numbers of confirmed cases, cured cases and deaths in Wuhan city from 10 January to 20 March, 2020 to estimate unknown parameters and the effective reproduction number. Sensitivity analysis was conducted to investigate the impact of a shortage of hospital beds on the COVID-19 outbreak. Results: Even with strong prevention and control measures in Wuhan, slowing down of the supply rate, reducing the maximum capacity and delaying the intervention time of supplementing hospital beds aggravated the outbreak severity by magnifying the cumulative numbers of confirmed cases and deaths, prolonging the period of the outbreak in Wuhan, enlarging the value of the effective reproduction number during the outbreak and postponing the time when the threshold value is reduced to 1. Conclusions: The quick establishment of the Huoshenshan and Leishenshan Hospitals in a short time and the deployment of mobile cabin hospitals played important roles in containing the COVID-19 outbreak in Wuhan, providing a model for other countries to provide more hospital beds for COVID-19 patients faster and earlier.
Subject(s)
COVID-19 , DeathABSTRACT
Objective@#In order to master the epidemic trend of corona virus disease 2019 (COVID-19) and evaluate the effect of prevention and control, we evaluate the epidemic dynamics of COVID-19 in mainland China, Hubei province, Wuhan city and other provinces outside Hubei from January 16 to February 14, 2020.@*Methods@#We collected the daily number of new confirmed COVID-19 cases by nucleic acid detection reported by the National Health Commission from January 16, 2020 to February 14, 2020. The analysis includes the epidemic curve of the new confirmed cases, multiple of the new confirmed cases for period-over-period, multiple of the new confirmed cases for fixed-base, and the period-over-period growth rate of the new confirmed cases.@*Results@#From January 16 to February 14, 2020, the cumulative number of new confirmed cases of COVID-19 in mainland China was 50 031, including 37 930 in Hubei province, 22 883 in Wuhan city and 12 101 in other provinces outside Hubei. The peak of the number of new confirmed cases in other provinces outside Hubei was from January 31 to February 4, 2020, and the peak of new confirmed cases in Wuhan city and Hubei province was from February 5 to February 9, 2020. The number of new confirmed cases in other provinces outside Hubei showed a significant decline (23% compared with the peak) from February 5 to February 9, 2020, while the number of new confirmed cases in Wuhan city (30% compared with the peak) and Hubei Province (37% compared with the peak) decreased significantly from February 10 to February 14, 2020.@*Conclusion@#The epidemic prevention and control measures taken by the state and governments at all levels have shown very significant effects, effectively curbing the spread of the COVID-19 epidemic in China.