Immunogenicity and safety of heterologous mRNA-1273/MVC-COV1901 vaccination versus homologous mRNA1273 vaccination: A randomized, double-blind controlled study.

BACKGROUND/PURPOSE: MVC-COV1901 is a protein vaccine based on the same SARS-CoV-2 strain used in mRNA vaccine mRNA-1273. Data are lacking on immunogenicity and safety of MVC-COV1901 as heterologous boost for people already received one dose of mRNA-1273. METHODS: This is a randomized, double-blind trial that recruited adults aged 20-70 years who previously received a single dose of mRNA-1273 vaccine and were randomly assigned in a 1:1 ratio to receive a second dose with the homologous vaccine or protein-based MVC-COV1901 8-12 weeks after the first dose. The primary outcome was neutralizing antibody titers in terms of the geometric mean titer (GMT) 14 days after the second dose. Safety was assessed in all participants who received a dose of the study vaccine. The study is registered with ClinicalTrials.gov (NCT05079633). RESULTS: From September 30 to November 5, 2021, 144 participants were enrolled and randomly assigned to the MVC-COV1901 boost group (n = 72) or the mRNA-1273 boost group (n = 72). The neutralizing antibodies on Day 15 and the anti-SARS-CoV-2 IgG titers on Day 15 and 29 of homologous mRNA-1273 were significantly higher than those of heterologous mRNA-1273/MVC-COV1901. Cellular immune responses were comparable in both groups. However, adverse events were much more frequent after the mRNA-1273 boost than after the MVC-COV1901 boost. CONCLUSION: Our results show that heterologous boost with MVC-COV1901 yielded an inferior immunogenicity but significantly fewer adverse events, compared with homologous boost with mRNA-1273. In people experienced severe adverse events after prime dose of mRNA-1273, as well as in periods when the supply of mRNA-1273 is limited, MVC-COV1901 could serve as an acceptable alternative heterologous boost.

Preventing and controlling intra-hospital spread of COVID-19 in Taiwan - Looking back and moving forward.

COVID-19 has exposed major weaknesses in the healthcare settings. The surge in COVID-19 cases increases the demands of health care, endangers vulnerable patients, and threats occupational safety. In contrast to a hospital outbreak of SARS leading to a whole hospital quarantined, at least 54 hospital outbreaks following a COVID-19 surge in the community were controlled by strengthened infection prevention and control measures for preventing transmission from community to hospitals as well as within hospitals. Access control measures include establishing triage, epidemic clinics, and outdoor quarantine stations. Visitor access restriction is applied to inpatients to limit the number of visitors. Health monitoring and surveillance is applied to healthcare personnel, including self-reporting travel declaration, temperature, predefined symptoms, and test results. Isolation of the confirmed cases during the contagious period and quarantine of the close contacts during the incubation period are critical for containment. The target populations and frequency of SARS-CoV-2 PCR and rapid antigen testing depend on the level of transmission. Case investigation and contact tracing should be comprehensive to identify the close contacts to prevent further transmission. These facility-based infection prevention and control strategies help reduce hospital transmission of SARS-CoV-2 to a minimum in Taiwan.

SARS-CoV-2 infection among healthcare workers whom already received booster vaccination during epidemic outbreak of omicron variant in Taiwan.

BACKGROUND/PURPOSE: Healthcare workers (HCWs) are at risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection due to occupational exposure. We aim to investigate the prevalence and risk factors of SARS-CoV-2 infection among HCWs during epidemic outbreak of omicron variant in Taiwan. METHODS: Sequential reserved serum samples collected from our previous study during December 2021 and July 2022 were tested for antibodies against SARS-CoV-2 nucleocapsid protein (NP). Diagnosis of SARS-CoV-2 infection was defined as positive either of anti-SARS-CoV-2 nucleoprotein, rapid antigen test or polymerase chain reaction. Retrospective chart review and a questionnaire were used to access the symptoms and risk factors for SARS-CoV-2 infection. RESULTS: Totally 300 participants (69.3% female) with a median age of 37.9 years were enrolled. A significant increase incidence of SARS-CoV-2 infection was found before and during community outbreak (11.91 versus 230.93 per 100,000 person-days, P < 0.001), which was a trend paralleling that observed in the general population. For 61 SARS-CoV-2 infected participants, nine (14.8%) were asymptomatic. Multivariate analysis revealed recent contact with a SARS-CoV-2 infected household (odds ratio [OR], 7.01; 95% confidence interval [95% CI], 3.70-13.30; P < 0.001) and co-existed underlying autoimmune diseases (OR, 4.46; 95% CI, 1.28-15.51; P = 0.019) were significant risk factors associated with acquisition of SARS-CoV-2 infection among HCWs. CONCLUSION: Community factors, such as closely contact with SARS-CoV-2 infected individuals and underlying immune suppression status, were significant factors for acquisition of SARS-CoV-2 infection among HCWs. We suggest the application of appropriate infection control measures for HCWs should be maintained to reduce risk of SARS-CoV-2 infection.

Safety and immunogenicity of homologous versus heterologous booster dose with AZD1222, mRNA-1273, or MVC-COV1901 SARS-CoV-2 vaccines in adults: An observer-blinded, multi-center, phase 2 randomized trial.

OBJECTIVES: To report the safety and immunogenicity profile of a protein subunit vaccine (MVC-COV1901) compared to AZD1222 and mRNA-1273 when given as a third (booster) dose to individuals who have completed different primary vaccine regimens. METHODS: Individuals were classified according to their primary vaccine regimens, including two-dose MVC-COV1901, AZD1222, or mRNA-1273. A third dose of either half-dose MVC-COV1901, full-dose MVC-COV1901, standard-dose AZD1222, half-dose mRNA-1273 was administered in a 1:1:1:1 treatment ratio to individuals with an interval range of 84-365 days after the second dose. Endpoints included safety, humoral immunogenicity, and cell-mediated immune response on trial days 15 and 29. Exploratory endpoint included testing against variants of concern (Omicron). RESULTS: Overall, 803 participants were randomized and boosted - 201 received half-dose MVC-COV1901, 196 received full-dose MVC-COV1901, 203 received AZD1222, and 203 received half-dose mRNA-1273. Reactogenicity was mild to moderate, and less in the MVC-COV1901 booster group. Heterologous boosting provided the best immunogenic response. Boosting with mRNA-1273 in MVC-COV1901 primed individuals induced the highest antibody titers, even against Omicron, and cell-mediated immune response. CONCLUSIONS: Overall, MVC-COV1901 as a booster showed the best safety profiles. MVC-COV1901 as a primary series, with either homologous or heterologous booster, elicited the highest immunogenic response. CLINICALTRIALS: gov registration NCT05197153.

Factors associated with viral rebound among COVID-19 patients receiving oral antivirals.

BACKGROUND: COVID-19 rebound is usually reported among patients experiencing concurrent symptomatic and viral rebound. But longitudinal viral RT-PCR results from early stage to rebound of COVID-19 was less characterized. Further, identifying the factors associated with viral rebound after nirmatrelvir-ritonavir (NMV/r) and molnupiravir may expand understanding of COVID-19 rebound. METHODS: We retrospectively analyzed clinical data and sequential viral RT-PCR results from COVID-19 patients receiving oral antivirals between April and May, 2022. Viral rebound was defined by the degree of viral load increase (ΔCt ≥ 5 units). RESULTS: A total of 58 and 27 COVID-19 patients taking NMV/r and molnupiravir, respectively, were enrolled. Patients receiving NMV/r were younger, had fewer risk factors for disease progression and faster viral clearance rate compared to those receiving molnupiravr (All P < 0.05). The overall proportion of viral rebound (n = 11) was 12.9%, which was more common among patients receiving NMV/r (10 [17.2%] vs. 1 [3.7%], P = 0.16). Of them, 5 patients experienced symptomatic rebound, suggesting the proportion of COVID-19 rebound was 5.9%. The median interval to viral rebound was 5.0 (interquartile range, 2.0-8.0) days after completion of antivirals. Initial lymphopenia (<0.8 × 109/L) was associated with viral rebound among overall population (adjusted odds ratio [aOR], 5.34; 95% confidence interval [CI], 1.33-21.71), and remained significant (aOR, 4.50; 95% CI, 1.05-19.25) even when patients receiving NMV/r were considered. CONCLUSION: Our data suggest viral rebound after oral antivirals may be more commonly observed among lymphopenic individuals in the context of SARS-CoV-2 Omicron BA.2 variant.

Impact of coronavirus disease on the HIV testing and health care delivery at a university hospital in Taiwan, 2020-2021

Background To contain the coronavirus disease 2019 (Covid-19) pandemic, non-pharmacologic interventions, including lockdown and social distancing, may have adverse impact on access to HIV testing and care. This study investigated the impact of Covid-19 on HIV testing and care at a major hospital in Taiwan in 2020-2021. Methods The numbers of clients seeking anonymous HIV voluntary counseling and testing were compared 2 years before (2018-2019) and 2 years after Covid-19 outbreak (2020-2021). People living with HIV (PLWH) who sought care at the hospital during 2018-2021 were included to examine the status of HIV care delivery and disposition. Results The annual number of HIV screening tests performed had significantly decreased from 2,507 and 2,794 in 2018 and 2019, respectively, to 2,161 and 1,737 in 2020 and 2021, respectively. The rate of discontinuation of HIV care among PLWH was 3.7% in 2019, which remained unchanged in 2020 (3.7%) and 2021 (3.8%). The respective percentage of annual plasma HIV RNA testing <2 times increased from 8.4% and 7.8% in 2018 and 2019 to 7.0% and 10.7% in 2020 and 2021, so was that of annual syphilis testing <2 times (10.1% and 8.8% to 7.9% and 12.0%). The rates of plasma HIV RNA <200 copies/ml ranged from 97.0% to 98.1% in 2018-2021. Conclusions During the Covid-19 pandemic, access to HIV counseling and testing was significantly limited. While the number of HIV-related testing decreased, the impact of Covid-19 on the continuity of antiretroviral therapy and viral suppression among PLWH appeared to be minimal in Taiwan.

Prospective health surveillance for COVID-19 among health care workers at a university medical center in Taiwan, January to June 2020.

BACKGROUND: Healthcare personnel (HCP) at the front line of care are exposed to occupational hazards that place them at risk for infection, which then endanger patient safety and compromise the capability of the healthcare workforce. As of March 8, 2021 more than 420,170 HCP in US had been infected with SARS CoV-2 with 1388 deaths. In two Taiwan hospitals COVID-19 outbreaks involved HCP and resulted in shutdown of service. This report describes our prospective health surveillance of the HCP and COVID-19 containment measures in a teaching hospital in Taiwan during Jan. 1 through June 30, 2020. METHODS: We prospectively monitored incidents, defined as an HCP with the predefined symptoms, reported by HCP through the web-based system. HCP were managed based on an algorithm that included SARS CoV-2 RNA PCR testing. Infection prevention and control policy/practice were reviewed. RESULTS: This hospital took care of 17 confirmed COVID-19 cases during the study period and the first Case was admitted on January 23, 2020. Among the 14,210 HCP, there were 367 incident events. Of 283 HCP tested for SARS CoV-2, 179 had predefined symptoms. These included 10 HCP who met the national case definition for COVID-19 infection and 169 based on Extended COVID-19 Community Screening program. The other 104 asymptomatic HCP were tested based on hospital policy. All of them had tested negative. CONCLUSION: We attribute our success in preventing COVID-19 infections among HCP to rapid, proactive, decisive, integrated national and institutional response in the early stages of the epidemic.

Dose-Related Aberrant Inhibition of Intracellular Perforin Expression by S1 Subunit of Spike Glycoprotein That Contains Receptor-Binding Domain from SARS-CoV-2.

Studies had shown that severe cases of COVID-19 tend to have high viral loads and correlate with functional impairment of cytotoxic lymphocytes, and the features of cytokine storm syndrome are similar to manifestations of severe influenza that have been partially explained by suppressed perforin expression. To test the hypothesis that the spike glycoprotein from SARS-CoV-2 may inhibit the perforin expression, we determined the kinetics of immune responses of CD8+ T cells to low dose (LD) or high dose (HD) of S1 stimulation through an in vitro dendritic cell (DC)-T cell model over seven days of incubation. The cytotoxic activity and intracellular perforin expression of CD8+ T cells induced by HD-S1-presenting DCs were aberrantly lower than those induced by LD-S1-presenting DCs from day three of incubation. Discrepantly, the levels of lymphoproliferation and cytokine (interferon-γ and tumor necrosis factor-α) production induced by HD-S1-presenting DCs were significantly higher than those induced by LD-S1-presenting DCs from day four. The dose-related responses between doses of S1 and intracellular perforin expression showed a significant linear correlation with a negative slope. In conclusion, the S1 subunit may suppress the perforin expression in CD8+ T cells to decrease the cytotoxic capacity to kill spike-presenting cells in a dose-dependent manner; the persistence of antigen presentation may result in an overproduction of interferon-γ and subsequent proinflammatory cytokines. That may help explain the insufficient cytotoxicity against high quantities of viruses or highly replicated strains of SARS-CoV-2 in severe cases of COVID-19.

A cross-sectional seroprevalence for COVID-19 among healthcare workers in a tertially care hospital in Taiwan.

BACKGROUND: Healthcare workers (HCWs) are at the frontline during the pandemic of COVID-19 globally. According to the WHO situation report at April 17, there were 22, 073 HCWs contracted the infection. Whether the infection control policy and practice in the hospital setting can protect the HCWs is an important issue. METHODS: We performed a cross-sectional serology study in a tertiary care hospital in Taiwan to explore the sero-prevalence rate among HCWs. The participants are enrolled on a voluntary basis. A structured questionnaire was collected to gather the epidemiology character and risk factors for potential exposure. ELISA tests as Architect SARS-CoV-2 IgG (Abbott) and Elecsys Anti-SARS-CoV-2 assay (Roche) were used to detect antibody responses. If any of the tests was positive, a western blot assay was used for confirmation. RESULTS: There were 194 HCWs participated during July 1 to Aug. 31, 2020. The mean age was 36.3 ± 10.4. More than half of the participants had possible hospital associated risk for COVID-19 exposure (110/192, 57.3%) and 64 had possible community risk for COVID-19 exposure (64/194, 33.0%). There was only one participant had positive test by Architect IgG test and confirmed to be negative for seasonal coronavirus and SARS-CoV-2 antibody. (Mikrogen Diagnostik, Germany). CONCLUSION: The cross-sectional serology study in a tertiary care hospital in Taiwan revealed no HCWs had positive serology response to SARS-CoV-2. We believe that the infection control policy and practice in the hospital and in the community are both important to prevent the disease transmission.