Vaccine effectiveness in symptom and viral load mitigation in COVID-19 breakthrough infections in South Korea.

OBJECTIVES: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine effectiveness in coronavirus disease (COVID-19) patients with breakthrough infections has not been established in South Korea. To address this, we assessed the impact of vaccination on symptom occurrence and viral load. METHODS: We performed a retrospective cohort study of 9,030 COVID-19 patients enrolled between February and November 2021. The impact of vaccination on the incidence of symptoms and viral load as indicated by cycle threshold (Ct) values of RdRp and E genes was evaluated using relative risks (RRs) and 95% confidence intervals (95% CIs). RESULTS: Compared with unvaccinated patients, fully vaccinated patients were associated with a reduced symptom onset of cough, sputum, and myalgia in COVID-19 patients (RR (95% CI) = 0.86 (0.75-0.99) for cough; RR (95% CI) = 0.74 (0.56-0.98) for sputum; RR (95% CI) = 0.65 (0.53-0.79) for myalgia, respectively). Additionally, lower risk of high viral load, Ct value of RdRp gene <15 or Ct value of E gene <15, was observed especially in fully vaccinated patients younger than 40 years ((RR (95% CI) = 0.69 (0.49-0.96) for RdRp gene; (RR (95% CI) = 0.71 (0.53-0.95) for E gene). CONCLUSION: SARS-CoV-2 vaccination was associated with a reduced risk of COVID-19 symptoms as well as decreased viral load, especially in patients younger than 40 years.

Identification of potential serum biomarkers in mercury-treated mice using a glycoproteomic approach.

Mercury is a well-recognized health hazard and a deleterious environmental contaminant. Exposure to mercury can cause neurotoxic manifestations, nephrotoxicity, and immune function alterations; however, the mechanisms and related proteins responsible for these effects are still unclear. Our goal is to understand the relationship between the toxicity of mercury and the proteins affected by this toxic heavy metal and to define biomarkers for mercury intoxication. Two different forms of mercury, organic methylmercury or inorganic mercury sulfide, were orally administered to the mice for 4 weeks. To reduce complexity of the serum proteome, we enriched glycoproteins from mice serum with lectin concanavalin A resin, and the tryptic peptides of the purified glycoproteins were subjected to nanoultra performance liquid chromatography-Quadrupole time-of-flight for identification and label-free quantification. In this study, we characterized approximately 209 proteins from mice serum, and, among them, 21 proteins were differentially expressed in organic methylmercury-treated mice serum compared with the control group. Two proteins, serum amyloid P component (SAP) and inter α-trypsin inhibitor heavy chain 4 (ITI-H4), were upregulated in organic methylmercury-treated mice and confirmed with different doses of both types of mercury by Western blot analysis. Results of immunohistochemistry also confirmed the validity of SAP and ITI-H4 as biomarker candidates for organic methylmercury exposure. Findings of this study may assist in understanding the relationship between toxicity of mercury and upregulated proteins in mouse serum. Furthermore, the proteins identified here might be used as biomarker candidates in mercury intoxication.