ABSTRACT
Currently, the majority of the global population has been vaccinated with the COVID-19 vaccine, and characterization studies of antibodies in vivo from Omicron breakthrough infection and naive infection populations are urgently needed to provide pivotal clues about accurate diagnosis, treatment, and next-generation vaccine design against SARS-CoV-2 infection. We showed that after infection with Omicron-BA.2, the antibody levels of specific IgM against the Wuhan strain and specific IgG against Omicron were not significantly elevated within 27 days of onset, Interestingly, in this study, the levels of humoral immunity against Omicron specific IgM were significantly increased after breakthrough infection, suggesting that the detection of Omicron specific IgM antibodies can be used as a test criterion of Omicron breakthrough infection. In addition, we observed that serums from unvaccinated individuals and the majority of vaccinated infections possessed only low or no neutralizing activity against Omicron at the onset of Omicron breakthrough infections, and at the later stage of Omicron-BA.2 breakthrough infection, levels of neutralization antibody against the Wuhan and Omicron strains were elevated in infected individuals. The findings of this study provide important clues for the diagnosis of Omicron breakthrough infections, antibody characterization studies, and the design of next-generation vaccines for COVID-19.
Subject(s)
COVID-19ABSTRACT
Background: To analyze the efficacy and safety of SARS-CoV-2 inactivated vaccine in people living with HIV (PLWH).Methods: A total of 143 PLWH were included in the study. All patients were confirmed with HIV-1 infection. We also enrolled 50 healthy individuals vaccinated with two doses of SARS-CoV-2 vaccine as controls. A commercially available magnetic chemiluminescence enzyme immunoassay kit was used to detected serum IgG and IgM against SARS-CoV-2.Findings: Serum levels of SARS-CoV-2-specific IgG were significantly higher in the control group than in the PLWH group (P=0.001). Overall, 76% of individuals in the control group achieved IgG seroconversion after vaccination compared with 58% in the PLWH group (P=0.024). The time after vaccination in IgG seronegative PLWH was significantly longer compared with PLWH with IgG seropositive (43.38 ± 34.96 vs 30.27 ± 20.12 days, P=0.005). In PLWH with IgG seropositivity, CD4+ T cell counts before antiretroviral therapy (ART) (P=0.015) and at IgG detection (P<0.001) were higher. Multivariable analysis indicated CD4+ T cells at IgG detection (OR=1.004, P=0.006) and time after vaccination (OR=0.977, P=0.014) were independently associated with humoral response in PLWH after vaccination. Neutralizing antibody (NeuAb) titers in PLWH against wild type SARS-CoV-2 were similar compared with the Control group (P=0.160). The proportion of seropositive NeuAb against wild type SARS-CoV-2 were also similar (95% in Control group vs 97% in PLWH group, P=0.665). Similar results were obtained when NeuAb were detected against the delta variants with similar titers (P=0.355) and with similar proportion of humoral response (P=0.588). All side effects observed in our study were mild and self-limiting. There was no significant difference in occurrence of side effects in the control and PLWH groups. Interpretation: The inactivated COVID-19 vaccine appears to be safe with good immunogenicity in PLWH.Funding: This study was supported by Clinical Research Startup Program of Southern Medical University by High-level University Construction Funding of Guangdong Provincial Department of Education (No. LC2016PY003).Declaration of Interest: None of the authors have competing interests to disclose.Ethical Approval: The study was performed in accordance with the Declaration of Helsinki and was approved by the Institutional Ethics Committee of Nanfang Hospital (NFEC-2021-178).
Subject(s)
Immunologic Deficiency Syndromes , HIV Infections , COVID-19ABSTRACT
We report the first local transmission of the SARS-CoV-2 Delta variant in mainland China. All 167 infections could be traced back to the first index case. Daily sequential PCR testing of the quarantined subjects indicated that the viral loads of Delta infections, when they first become PCR+, were on average ~1000 times greater compared to A/B lineage infections during initial epidemic wave in China in early 2020, suggesting potentially faster viral replication and greater infectiousness of Delta during early infection. We performed high-quality sequencing on samples from 126 individuals. Reliable epidemiological data meant that, for 111 transmission events, the donor and recipient cases were known. The estimated transmission bottleneck size was 1-3 virions with most minor intra-host single nucleotide variants (iSNVs) failing to transmit to the recipients. However, transmission heterogeneity of SARS-CoV-2 was also observed. The transmission of minor iSNVs resulted in at least 4 of the 30 substitutions identified in the outbreak, highlighting the contribution of intra-host variants to population level viral diversity during rapid spread. Disease control activities, such as the frequency of population testing, quarantine during pre-symptomatic infection, and level of virus genomic surveillance should be adjusted in order to account for the increasing prevalence of the Delta variant worldwide.
ABSTRACT
Summary We report the first local transmission of the SARS-CoV-2 Delta variant in mainland China. All 167 infections could be traced back to the first index case. Daily sequential PCR testing of the quarantined subjects indicated that the viral loads of Delta infections, when they first become PCR+, were on average ∼1000 times greater compared to A/B lineage infections during initial epidemic wave in China in early 2020, suggesting potentially faster viral replication and greater infectiousness of Delta during early infection. We performed high-quality sequencing on samples from 126 individuals. Reliable epidemiological data meant that, for 111 transmission events, the donor and recipient cases were known. The estimated transmission bottleneck size was 1-3 virions with most minor intra-host single nucleotide variants (iSNVs) failing to transmit to the recipients. However, transmission heterogeneity of SARS-CoV-2 was also observed. The transmission of minor iSNVs resulted in at least 4 of the 30 substitutions identified in the outbreak, highlighting the contribution of intra-host variants to population level viral diversity during rapid spread. Disease control activities, such as the frequency of population testing, quarantine during pre-symptomatic infection, and level of virus genomic surveillance should be adjusted in order to account for the increasing prevalence of the Delta variant worldwide.
ABSTRACT
Background: On December 31, 2019, an outbreak of COVID-19 in humans was reported in Wuhan, and then spread fast to other provinces, China. We analyzed data from field investigations and genetic sequencing to describe the evidence and characteristics of human-to-human transmission in Guangdong Province. Methods: A confirmed COVID-19 case was defined if a suspected case was verified with positive of SARS-CoV-2 in throat swabs, nasal swabs, bronchoalveolar lavage fluid (BALF), or endotracheal aspirates by real-time reverse transcriptase polymerase chain reaction assay (RT-PCR) or genetic sequencing. Field investigations were conducted for each confirmed case. Clinical and demographic data of confirmed cases were collected from medical records. Exposure and travel history were obtained by interview. Results: A total of 1,151 confirmed cases were identified as of February 10, 2020 in Guangdong Province, China. Of them, 697 (60.1%) cases were from 234 cluster infections. Two hundred and fourteen (18.6%) were secondary cases, in which 144 cases were from family cluster infections. With the epidemic continuing, although familial cluster events were dominated, community cluster events increased with a nosocomial event. The whole genomes within the same family cluster infections were identical, and presented a few unique single nucleotide variants (SNVs) compared with SARS-CoV-2 identified on December 2019 in Wuhan. Conclusions: We observed evident human-to-human transmissions of SARS-CoV-2 in Guangdong, China. Although most of them were from family cluster infections, community and nosocomial infections were increasing. Our findings indicate that human-to-human transmission risks are transferring from family to community in Guangdong Province.