ABSTRACT
Background: Although effective vaccines have been developed against coronavirus disease 2019 (COVID-19), the level of neutralizing antibodies (NAbs) induced after vaccination in the real world is still unknown. The aim of this work was to evaluate the level and persistence of NAbs induced by two inactivated COVID-19 vaccines in China. Methods: Serum samples were collected from 1,335 people aged 18 years and over who were vaccinated with an inactivated COVID-19 vaccine at Peking University People's Hospital from January 19 to June 23, 2021, for the detection of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. Results: The positive rate for NAbs against SARS-CoV-2 was 79-91% from the first month to the second month after the second vaccine dose. The gradual decline in positivity rate for NAb response was observed from 78% at 3 months post-vaccination to 0% at 12 months post-vaccination. When there was a 21-day interval between the two doses of vaccine, the NAb positivity rate was 0% 6 months after the second dose. NAb levels were significantly higher when the interval between two doses were 3-8 weeks than when it was 0-3 weeks (χ2 = 14.04, p < 0.001). There was a linear correlation between NAbs and IgG antibodies in 1,335 vaccinated patients. NAb levels decreased in 31 patients (81.6%) and increased in 7 patients (18.4%) over time in the series of 38 patients after the second vaccination. The NAb positivity rate was significantly higher in 18- to 40-year-old subjects than in 41- to 60-year-old subjects (t = -1.959, p < 0.01; t = 0.839, p < 0.01). Conclusion: The NAb positivity rate was the highest at the first and second month after the second dose of vaccine, and gradually decreased over time. With a 21-day interval between two doses of vaccine, neutralizing antibody levels persisted for only 6 months after the second dose of vaccine. Therefore, a third vaccine dose is recommended. Our results suggest that in cases in which NAbs cannot be detected, IgM/IgG antibodies can be detected instead. The level of NAbs produced after vaccination was affected by age but not by sex. Our results suggest that an interval of 21 to 56 days between shots is suitable for vaccination.
ABSTRACT
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) shows a high degree of homology with SARS-CoV. They share genes, protein sequences, clinical manifestations, and cellular entry patterns. Thus, SARS research may serve helpful in gaining a better understanding of the current coronavirus disease 2019 (COVID-19) pandemic. Serum antibodies from convalescent patients with SARS collected in 2018 were used to target the recombinant SARS-CoV-2 spike protein via a chemiluminescence microsphere immunoassay. Antibodies of convalescent patients with SARS exhibited serous immune cross-reactivity with the SARS-CoV-2 spike protein. The serous antibodies, excluding S22 of convalescent patients with SARS, did not competitively inhibit the binding of SARS-CoV-2 spike protein to ACE2. T cellular immunity research was conducted in vitro using peripheral blood mononuclear cells (PBMCs) stimulated by pooled peptide epitopes 15 years post-infection. Interferon gamma was detected and the PBMC transcriptomic profile was obtained. The heatmap of the transcriptomic profile showed that mRNAs and circRNAs of the SARS group clustered together after being stimulated by the peptide epitope pool. Differentially expressed mRNAs were most significantly enriched in immunity and signal transduction (P < 0.01). SARS elicits cytokine and chemokine responses, partially consistent with previously published data about COVID-19. Overall, our results indicate that antibodies from convalescent patients with SARS persisted for 15 years and displayed immune cross-reactivity with the SARS-CoV-2 spike protein. The immune status of patients with SARS 15 years post-infection may provide a better understanding of the future immune status of patients with COVID-19.
Subject(s)
COVID-19 , Leukocytes, Mononuclear , Antibodies, Viral , Humans , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , TranscriptomeABSTRACT
At the end of 2019, an outbreak of pneumonia took place caused by a new coronavirus (SARS-CoV-2 virus), named coronavirus disease 2019 (COVID-19). A series of strict prevention and control measures were then implemented to reduce the spread of the epidemic. Influenza, another respiratory tract virus, may also respond to these measures. To assess the impact of these measures, we used the total number of passengers movement in mainland China from 2018 to 2020 and daily number of railway passenger flow during the 2020 Spring Festival travel rush to reflect the population movement and to analyze newly and cumulatively confirmed COVID-19 and influenza cases. We found that implementing the series of measures against COVID-19 mitigated both COVID-19 and influenza epidemics in China. Prevention and control measures for COVID-19 might be used to control respiratory tract infections to reduce the national health economic burden caused by these pathogens.
ABSTRACT
Under the ongoing COVID-19 prevention and control measures in China, increasing the laboratory severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid testing capacity has become the top priority. Since the COVID-19 outbreak in Xinfadi market in Beijing in June 2020, large-scale screening of key populations has been carried out, challenging the nucleic acid testing capabilities of hospital laboratories. Therefore, within 48 hours, Peking University People's Hospital (PKUPH) transformed a non-nucleic acid testing laboratory into a SARS-CoV-2 nucleic acid testing laboratory. Based on the original structure of the building, we adapted measures to local conditions, sorted out a new testing process, and quickly started testing for COVID-19. The nucleic acid testing process has been optimized, including quality control, personal operating specifications, and the timeliness of the release of LIS results to form closed-loop management. This high-throughput COVID-19 testing optimization process provides a reference model for other countries that are fighting the epidemic.