Heterologous vaccination (ChAdOx1 and BNT162b2) induces a better immune response against the omicron variant than homologous vaccination.

BACKGROUND: The ongoing COVID-19 pandemic has seen the emergence of numerous novel variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. In this study, we compared the efficacy of three different forms of immunization against the wild-type, delta, and omicron variants of the virus: two doses of the BNT or AZ vaccine (BNT/BNT or AZ/AZ) as homologous vaccination, three doses of AZ/AZ/BNT as heterologous vaccination, and naturally occurring immunization in severe COVID-19 cases. METHODS: We collected serum samples from vaccine recipients (67 receiving BNT/BNT, 111 receiving AZ/AZ, and 18 receiving AZ/AZ/BNT) and 46 patients who were admitted to the hospital with severe COVID-19. Blood samples were taken one month after the last injection and the efficacy of the vaccination was determined using the surrogate virus neutralization test (sVNT), with a positive result defined as an inhibition rate of over 30%. Serum samples from COVID-19 patients were taken at various points during their hospitalization and tested for inhibition rates. RESULTS: Our results indicated that there was no notable difference in the levels of neutralizing antibodies (nAb) in vaccine recipients and patients against the wild-type and delta variants. However, when it came to the omicron variant, the vaccine recipients had significantly lower nAb titers. Among the vaccine recipients, those who received a booster dose of BNT after their first two doses of AZ (AZ/AZ/BNT) demonstrated the highest level of protection against the omicron variant at 44.4%, followed closely by the COVID-19 patients. In analyzing the serial samples taken from hospitalized COVID-19 patients, we observed that their inhibition rates against the wild-type and delta variants improved over time, while the inhibition rate against the omicron variant decreased. CONCLUSION: In conclusion, our findings suggest that heterologous booster vaccination after primary vaccination produces higher nAb titers and provides a higher level of protection against the omicron variant compared to primary vaccination alone. This protective effect was similar to that observed in patients with severe COVID-19.

Multisystem Inflammatory Syndrome in an Adult Following COVID-19 mRNA Vaccination: Successful Treatment With Medium-Dose Steroids and Colchicine.

Multisystem inflammatory syndrome in children and adults (MIS-C/A) was rarely reported as a complication of coronavirus disease 2019 (COVID-19) and potential adverse events following COVID-19 vaccination. Recently, the case definition of MIS-C/A was developed by the Brighton Collaboration Network. However, only a limited number of adult patients with MIS-A following immunization have been reported, and there is still little evidence for adequate treatment. A 57-year-old man presented with fever, headache, vomiting, and hypotension 24 days after receiving the second COVID-19 vaccination with the Pfizer-BioNTech vaccine. According to the Brighton Collaboration Case Definition, the patient met a definitive case of MIS-A after vaccination (level 1 of diagnostic certainty). After administration of medium-dose prednisolone (20 mg/d) with colchicine (1.2 mg/d), all symptoms and signs improved rapidly. The dose of prednisolone was gradually tapered from the third week, and the patient confirmed a full recovery without medication after 8 weeks. This is the first report showing that low-dose steroids in combination with colchicine may be an effective treatment option for MIS-A after vaccination.

Evaluation of R-FIND SARS-CoV-2 Neutralizing Antibody ELISA and FREND COVID-19 SP Rapid Fluorescence Immunoassay.

BACKGROUND: Serology testing is useful to determine the past infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: We evaluated the comparative performance of a newly developed neutralizing antibody test (R-FIND SARS-CoV-2 Neutralizing Antibody ELISA, SG Medical, Seoul, Korea) and a rapid fluorescence immunoassay (FREND™ COVID-19 SP, NanoEntek, Hwaseong, Korea) for the detection of SARS-CoV-2 spike protein antibody. They were compared with cPass™ SARS-CoV-2 Neutralization Antibody Detection Kit (Genscript Biotech, Piscataway, NJ, USA) and ADVIA Centaur SARS-CoV-2 Total (COV2T) (Siemens Healthineers, Erlangen, Germany). Forty COVID-19 samples and 80 negative samples were collected after nucleic acid tests. RESULTS: The positive percent agreement (%) of the kit in samples from 6 - 7 days, 8 - 14 days, and 15 - 45 days after symptom onset were as follows: R-FIND (83.3, 76.9, 95.2), cPass (83.3, 69.2, 90.5), FREND (66.6, 84.6, 100), and COV2T (66.6, 69.2, 76.2). The negative percent agreement (%) was 100, 97.5, 92.5, and 100 for R-FIND, cPass, FREND, and COV2T. The total agreement rate between the neutralizing antibody kits (R-FIND and cPass) was 96.7%. FREND showed high agreement with two neutralizing antibody kits (96.7% for R-FIND and 93.3% for cPass). CONCLUSIONS: R-FIND Neutralizing Antibody and FREND COVID-19 SP showed comparable detecting ability to commercial tests.

Adverse reactions and production of neutralizing anti-SARS-CoV-2 antibodies after ChAdOx1 COVID-19 vaccination: A cross-sectional study in a single center.

Adverse events following vaccination with the ChAdOx1 COVID-19 vaccine may be associated with the titer of neutralizing antibodies (NAbs) against SARS-CoV-2. In this cross-sectional study, a total of 82 HCWs who received the ChAdOx1 COVID-19 vaccine and did not have previous COVID-19 history were enrolled during March 2021. Blood samples were collected from HCWs 3 weeks after the first and second doses of vaccine, and NAbs were estimated using two types of commercially available kits, the cPass™ SARS-CoV-2 NAbs Kit (Genscript Biotech, Piscataway, NJ, USA) and R-FIND SARS-CoV-2 NAbs ELISA (SG Medical, Seoul, Korea). Median percent signal inhibition of NAbs was significantly higher after the second than after the first dose of vaccine, as determined using both the Genscript (median 43.1[IQR 71.2] vs. 93.6[83.1], p = 0.004) and R-FIND (53.2[82.6] vs. 76.8 [90.6], p = 0.03) kits. The percent signal inhibition of NAbs after the second dose of vaccine was higher in HCWs with than without systemic adverse events after the second dose, as determined using both the Genscript (p = 0.03) and R-FIND (p = 0.07) kits. The two doses of the ChAdOx1 vaccine induced high value of NAbs 3 weeks after vaccination. Immune responses were stronger in HCWs with than without adverse reactions after the second dose of ChAdOx1 vaccine.

Infection prevention and control practices for emergency surgery during the COVID-19 pandemic in a tertiary care hospital in South Korea.

•Proper risk assessment for COVID-19 should be implemented.•Appropriate infection prevention practices for perioperative management are important.•Hospitals should organize dedicated protocols considering its facilities and human resources.

Construction of a non-contact community treatment centre for asymptomatic and mildly symptomatic COVID-19 patients during the COVID-19 pandemic.

The explosive outbreak of COVID-19 led to a shortage of medical resources, including isolation rooms in hospitals, healthcare workers (HCWs) and personal protective equipment. Here, we constructed a new model, non-contact community treatment centres to monitor and quarantine asymptomatic and mildly symptomatic COVID-19 patients who recorded their own vital signs using a smartphone application. This new model in Korea is useful to overcome shortages of medical resources and to minimise the risk of infection transmission to HCWs.