Studies on Growth Characteristics and Cross-Neutralization of Wild-Type and Delta SARS-CoV-2 From Hisar (India)

Detection of active SARS-CoV-2 in cough aerosols from COVID-19 patients

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an airborne pathogen, but detection of infectious SARS-CoV-2 in air and in particular the introduction of the virus into the environment by different human expiratory manoeuvres is not well studied.

OBJECTIVES

The aim of this study was to investigate the presence of SARS-CoV-2 in cough from coronavirus disease of 2019 (COVID-19) in-patients and to study contamination of the virus in the patient's environment.

METHODS

Detection of SARS-CoV-2 in cough was analyzed by PCR, culture and imaging. Detection in cough was compared to presence of the virus in air and on surfaces from patient rooms.

RESULTS

Twenty-five patients in 21 rooms were included in the study. SARS-CoV-2 RNA was found in cough aerosols from 16 out of 22 patients that produced voluntary cough. As demonstrated by plaque-forming unit assays, active virus was isolated from 11 of these 16 patients. Using mainly molecular detection, the virus was also found in air, on high-contact surfaces, and no-touch surfaces from the room of the COVID-19 patients.

CONCLUSIONS

These results show that infectious SARS-CoV-2 circulating in air can originate from patient cough and should be considered against the risk of acquiring COVID-19 through inhalation.

p38-MAPK is prerequisite for the synthesis of SARS-CoV-2 protein

The inhibition of p38 mitogen-activated protein kinase (p38-MAPK) by small molecule chemical inhibitors was previously shown to impair severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication, however, mechanisms underlying antiviral activity remains unexplored. In this study, reduced growth of SARS-CoV-2 in p38-α knockout Vero cells, together with enhanced viral yield in cells transfected with construct expressing p38α, suggested that p38-MAPK is essential for the propagation of SARS-CoV-2. The SARS-CoV-2 was also shown to induce phosphorylation (activation) of p38, at time when transcription/translational activities are considered to be at the peak levels. Further, we demonstrated that p38 supports viral RNA/protein synthesis without affecting viral attachment, entry, and budding in the target cells. In conclusion, we provide mechanistic insights on the regulation of SARS-CoV-2 replication by p38 MAPK.

The course of infection with the Delta variant of COVID-19 in pregnancy: analysis of clinical, laboratory, and neonatal outcomes

Objective

This study aimed to examine the effects of infection with the Delta variant of coronavirus disease-2019 (COVID-19) on the clinical course, laboratory parameters, and neonatal outcome in pregnant women.

Material and Methods

A total of 96 pregnant women who tested positive for the Delta variant of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) causing COVID-19 were retrospectively examined. The pregnant women were divided into three groups: Asymptomatic; non-severe; and severe. Age, obstetric history, symptoms and findings, blood tests, medication and vaccination history, clinical course, and perinatal outcome of pregnant women were analyzed.

Results

Pregnant women who tested positive for the Delta variant of SARS-CoV-2 had an intensive care unit (ICU) admission rate of 9.4% and a mortality rate of 5.2%. Pregnant women in the severe disease group had significantly higher rates of preterm birth and cesarean section compared with the non-severe and asymptomatic group. Pregnant women in the severe group had high C-reactive protein (CRP) levels at the time of admission. White blood cell count (WBC) and procalcitonin levels were increased in clinical follow-up in women in the severe group.

Conclusion

The Delta variant of SARS-CoV-2 was found to increase mortality rates in pregnant women compared to pre-Delta variants of COVID-19. In pregnant women infected with the Delta variant, advanced gestational age at diagnosis, high CRP, WBC, and procalcitonin levels were significantly correlated with poor prognosis. Pregnant women infected with the Delta variant and with severe COVID-19 had an increased risk for preterm delivery and cesarean section. Although newborns of women with severe disease were found to have significantly higher rates of ICU admission, there was no significant difference in neonatal mortality rates. We recommend close monitoring of CRP, WBC, and procalcitonin levels, in addition to symptoms, in pregnant women infected with the Delta variant of SARS-CoV-2 and diagnosed in the third trimester.

Validation and Establishment of the SARS-CoV-2 Lentivirus Surrogate Neutralization Assay as a Prescreening Tool for the Plaque Reduction Neutralization Test

Neutralization assays are important for understanding and quantifying neutralizing antibody responses toward severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 lentivirus surrogate neutralization assay (SCLSNA) can be used in biosafety level 2 (BSL-2) laboratories and has been shown to be a reliable alternative approach to the plaque reduction neutralization test (PRNT). In this study, we optimized and validated the SCLSNA to assess its ability as a comparator and prescreening method to support the PRNT. Comparability between the PRNT and SCLSNA was determined through clinical sensitivity and specificity evaluations. Clinical sensitivity and specificity assays produced acceptable results, with 100% (95% confidence interval [CI], 94% to 100%) specificity and 100% (95% CI, 94% to 100%) sensitivity against ancestral Wuhan spike-pseudotyped lentivirus. The sensitivity and specificity against B.1.1.7 spike-pseudotyped lentivirus were 88.3% (95% CI, 77.8% to 94.2%) and 100% (95% CI, 94% to 100%), respectively. Assay precision measuring intra-assay variability produced acceptable results for high (50% PRNT [PRNT₅₀], 1:≥640), mid (PRNT₅₀, 1:160), and low (PRNT₅₀, 1:40) antibody titer concentration ranges based on the PRNT₅₀, with coefficients of variation (CVs) of 14.21%, 12.47%, and 13.28%, respectively. Intermediate precision indicated acceptable ranges for the high and mid concentrations, with CVs of 15.52% and 16.09%, respectively. However, the low concentration did not meet the acceptance criteria, with a CV of 26.42%. Acceptable ranges were found in the robustness evaluation for both intra-assay and interassay variability. In summary, the validation parameters tested met the acceptance criteria, making the SCLSNA method fit for its intended purpose, which can be used to support the PRNT. IMPORTANCE Neutralization studies play an important role in providing guidance and justification for vaccine administration and helping prevent the spread of diseases. The neutralization data generated in our laboratory have been included in the decision-making process of the National Advisory Committee on Immunization (NACI) in Canada. During the coronavirus 2019 (COVID-19) pandemic, the plaque reduction neutralization test (PRNT) has been the gold standard for determining neutralization of SARS-CoV-2. We validated a SARS-CoV-2 lentivirus surrogate neutralization assay (SCLSNA) as an alternative method to help support the PRNT. The advantages of using the SCLSNA is that it can process more samples, is less tedious to perform, and can be used in laboratories with a lower biosafety level. The use of the SCLSNA can further expand our capabilities to help fulfill the requirements for NACI and other important collaborations.

Safety and Immunogenicity of Inactivated COVID-19 Vaccines Among People Living with HIV in China

Purpose

Vaccination reduces the incidence of severe COVID-19 and death and effectively limits viral spread. Concerns have been raised about COVID-19 vaccine responses in the large population of HIV-infected patients. This study aims to explore the safety and immunogenicity of the inactivated COVID-19 vaccine in people living with HIV (PLWH).

Patients and Methods

All participants in this study already had their second dose of an inactivated COVID-19 vaccine at least 14 days earlier, without a history of SARS-CoV-2 infection. The primary safety outcomes were the incidence of adverse reactions and changes in CD4⁺ T-cell counts. SARS-CoV-2 IgG and neutralizing antibody responses to the D614G variant and delta variant were measured for immune response assessment.

Results

Forty-seven HIV-infected patients and 18 healthy donors (HDs) were enrolled in this study. Adverse reactions were mild or self-limiting and were reported in 19.1% of HIV-infected patients. Most PLWH developed antibody responses against the inactivated COVID-19 vaccine. The longitudinal analysis of antibody responses in PLWH (median interval between detection and complete vaccination, 59 days) showed that antibodies were maintained for at least three months, though their titers were reduced. However, the antibody-positive rates in PLWH were significantly lower than those in HDs. Additionally, compared to HDs (Geomean titers (GMT) of 165 for D614G and GMT of 72 for delta), the neutralizing antibody titers against the two variants in PLWH (GMT of 43 for D614G and GMT 13 for delta) were decreased significantly (p = 0.018 and p < 0.001, respectively). HIV-infected patients with CD4⁺T-cell counts ≤350 cells/μL appeared to exhibit a poor antibody response to inactivated vaccination.

Conclusion

Inactivated COVID-19 vaccines appear to be efficacious in PLWH. However, antibody responses in HIV-infected patients are inferior to those in healthy individuals, especially PLWH with lower CD4⁺T-cell counts.