Comprehensive analyses reveal the impacts of vaccination status and physiological variables in early infection on viral persistence in COVID-19 patients: a retrospective single-center cohort study

BACKGROUNDViral persistence is a crucial factor that influences the communicability of SARS-CoV-2 infection. However, the impacts of vaccination status and physiological variables on viral RNA shedding have not been adequately clarified. METHODSIn this study, we retrospectively collected the clinical records of 377 hospitalized COVID-19 patients, which contained unvaccinated patients and patients received two doses of an inactivated vaccine or an mRNA vaccine. Firstly, we analyzed the impacts of vaccination on disease severity and viral RNA persistence. Next, to clarify the impacts of physiological variables on viral RNA shedding in COVID-19 patients, we retrieved 49 laboratory variables and analyzed their correlations with the duration of viral RNA shedding. Finally, we established a multivariate regression model to predict the duration of viral RNA shedding. RESULTSOur results showed that both inactivated and mRNA vaccines significantly reduced the rate of moderate cases, while the vaccine related shortening of viral RNA shedding were only observed in moderate patients. Correlation analysis showed that 10 significant laboratory variables were shared by the unvaccinated mild patients and mild patients inoculated with an inactivated vaccine, but not by the mild patients inoculated with an mRNA vaccine. Moreover, we demonstrated that a multivariate regression model established based on the variables correlating with viral persistence in unvaccinated mild patients could predict the duration of viral shedding for all groups of patients. CONCLUSIONSVaccination contributed limitedly to the clearance viral RNA in COVID-19 patients. While, laboratory variables in early infection could predict the persistence of viral RNA.

Immunogenicity and safety of an inactivated SARS-CoV-2 vaccine in people living with HIV-1

BackgroundIt has been proven that inactivated COVID-19 vaccines are safe and effective in general population with intact immunity. However, their safety and immunogenicity have not been demonstrated in people living with HIV (PLWH). Methods42 HIV-1 infected individuals who were stable on cART and 28 healthy individuals were enrolled in this study. Two doses of an inactivated COVID-19 vaccine (BIBP-CorV) were given 4 weeks apart. The safety and reactogenicity of the vaccine were evaluated by observing clinical adverse events and solicited local and systemic reactions. Humoral responses were measured by anti-spike IgG ELISA and surrogate neutralization assays. Cell-mediated immune responses and vaccine induced T cell activation were measured by flow cytometry. FindingsAll the HIV-1 infected participants had a CD4+ T cell count of above 200 cells/L both at baseline and 4 weeks after vaccination. No solicited adverse reaction was observed among all participants. Similar binding antibody, neutralizing antibody and S protein specific T cell responses were elicited in PLWH and healthy individuals. Further analyses showed that PLWH with low baseline CD4+/CD8+ T cell ratios (<0{middle dot}6) generated lower antibody responses after vaccination than PLWH with medium (0{middle dot}6[~]1{middle dot}0) or high ([≥]1{middle dot}0) baseline CD4+/CD8+ T cell ratios (P<0{middle dot}01). The CD3+, CD4+ and CD8+ T cell counts of PLWH decreased significantly after vaccination, but it did not lead to any adverse clinical manifestation. Moreover, we found that the general burden of HIV-1 among the PLWH cohort decreased significantly (P=0{middle dot}0192) after vaccination. And the alteration of HIV-1 viral load was not significantly associated with the vaccine induced CD4+ T cell activation. InterpretationOur data demonstrate that the inactivated COVID-19 vaccine is safe and immunogenic in PLWH who are stable on cART with unsuppressed CD4 counts. FundingThis work was funded by the National Natural Science Foundation of China (Grant No. 81971559, 82041010). Research in contextO_ST_ABSEvidence before this studyC_ST_ABSThe safety and efficacy of inactivated COVID-19 vaccines have been validated in general population with intact immunity. However, their safety and immunogenicity have not been demonstrated in people living with HIV (PLWH). Added value of this studyOur study provides the first evidence to show humoral and cellular immune responses to an inactivated vaccine in PLWH who have been stable on cART with good CD4 cell counts. We found that participants with HIV-1 generated antibody and T cell responses comparable with those of healthy individuals after two-dose vaccination. The baseline CD4/CD8 ratios while not the absolute CD4+ T cell counts were shown to be associated with the magnitudes of vaccine induced antibody responses. Moreover, we showed that the vaccine induced T cell activation did not increase the viral burden in PLWH on cART. On the contrary, the levels of plasma HIV-1 RNA decreased among a significant percentage of PLWH. Implications of all the available evidenceOur data demonstrate that the inactivated COVID-19 vaccine is safe and immunogenic in PLWH who are stable on cART with unsuppressed CD4 counts and indicate that this vaccine might be protective and efficacious against COVID-19 for people with HIV.

Pre-existing antibodies targeting a dominant linear antibody epitope on SARS-CoV-2 S2 cross-reacted with commensal gut bacteria and shaped immune responses elicited by a candidate vaccine

The origins of pre-existing SARS-CoV-2 cross-reactive antibodies and their potential impacts on vaccine efficacy have not been fully clarified. In this study, we demonstrated that S2 was the prevailing target of the pre-existing S protein cross-reactive antibodies in both healthy human and SPF mice. A dominant antibody epitope was identified on the connector domain of S2 (1147-SFKEELDKYFKNHT-1160, P144), which could be recognized by pre-existing antibodies in both human and mouse. Through metagenomic sequencing and fecal bacteria transplant, we proved that the generation of S2 cross-reactive antibodies was associated with commensal gut bacteria. Furthermore, six P144 specific monoclonal antibodies were isolated from naive SPF mice and proved to cross-react with commensal gut bacteria collected from both human and mouse. Mice with high levels of pre-existing S2 cross-reactive antibodies mounted higher S protein specific binding antibodies, especially against S2, after being immunized with a SARS-CoV-2 S DNA vaccine. Similarly, we found that levels of pre-existing S2 and P144 reactive antibodies correlated positively with RBD specific binding antibody titers after two doses of inactivated SARS-CoV-2 vaccination in human. Finally, we provided data demonstrating that immunization of a SARS-CoV-2 S DNA vaccine could alter the gut microbiota compositions of mice.