Factors affecting turnaround time of SARS-CoV-2 sequencing for inpatient infection prevention and control decision making: analysis of data from the COG-UK HOCI study.

BACKGROUND: Barriers to rapid return of sequencing results can affect the utility of sequence data for infection prevention and control decisions. AIM: To undertake a mixed-methods analysis to identify challenges that sites faced in achieving a rapid turnaround time (TAT) in the COVID-19 Genomics UK Hospital-Onset COVID-19 Infection (COG-UK HOCI) study. METHODS: For the quantitative analysis, timepoints relating to different stages of the sequencing process were extracted from both the COG-UK HOCI study dataset and surveys of study sites. Qualitative data relating to the barriers and facilitators to achieving rapid TATs were included from thematic analysis. FINDINGS: The overall TAT, from sample collection to receipt of sequence report by infection control teams, varied between sites (median 5.1 days, range 3.0-29.0 days). Most variation was seen between reporting of a positive COVID-19 polymerase chain reaction (PCR) result to sequence report generation (median 4.0 days, range 2.3-27.0 days). On deeper analysis, most of this variability was accounted for by differences in the delay between the COVID-19 PCR result and arrival of the sample at the sequencing laboratory (median 20.8 h, range 16.0-88.7 h). Qualitative analyses suggest that closer proximity of sequencing laboratories to diagnostic laboratories, increased staff flexibility and regular transport times facilitated a shorter TAT. CONCLUSION: Integration of pathogen sequencing into diagnostic laboratories may help to improve sequencing TAT to allow sequence data to be of tangible value to infection control practice. Adding a quality control step upstream to increase capacity further down the workflow may also optimize TAT if lower quality samples are removed at an earlier stage.

Computational tools for aptamer identification and optimization

Aptamers are single-stranded DNA or RNA oligonucleotides that can selectively bind to a specific target. They are generally obtained by SELEX, but the procedure is challenging and time-consuming. Moreover, the identified aptamers tend to be insufficient in stability, specificity, and affinity. Thus, only a handful of aptamers have entered the practical use stage. Recently, computational approaches have demonstrated a significant capacity to assist in the discovery of high-performance aptamers. This review discusses the advances achieved in several aspects of computational tools in this field, as well as the new progress in machine learning and deep learning, which are used in aptamer identification and optimization. To illustrate these computationally aided processes, aptamer selections against SARS-CoV-2 are discussed in detail as a case study. We hope that this review will aid and motivate researchers to develop and utilize more computational techniques to discover ideal aptamers effectively. Copyright © 2022 Elsevier B.V.

Nirmatrelvir increases blood tacrolimus concentration in COVID-19 patients as determined by UHPLC-MS/MS method.

OBJECTIVE: Transplant recipients have a higher risk of SARS-CoV-2 infection owing to the use of immunosuppressive drugs like tacrolimus (FK506). FK506 and nirmatrelvir (NMV) (an anti-SARS-CoV-2 drug) are metabolized by cytochrome P450 3A4 and may have potential drug-drug interactions. It is important to determine the effect of NMV on FK506 concentrations. PATIENTS AND METHODS: Following protein precipitation from blood, FK506 and its internal standard (FK506-13C,2d4) were detected by ultra-high performance liquid chromatography/tandem mass spectrometry (UHPLC-MS/MS). Total 22 blood samples (valley concentrations) from two coronavirus disease 2019 (COVID-19) patients were collected and analyzed for FK506 concentrations. RESULTS: Blood levels of FK506 (0.5-100 ng/mL) showed good linearity. The UHPLC-MS/MS method was validated with intra- and inter-batch accuracies of 104.55-107.85%, and 99.52-108.01%, respectively, and precisions of < 15%. Mean blood FK506 concentration was 12.01 ng/mL (range, 3.15-33.1 ng/mL). Five-day co-administration with NMV increased the FK506 concentrations from 3.15 ng/mL to 33.1 ng/mL, returning to 3.36 ng/mL after a 9-day-washout. CONCLUSIONS: We developed a simple quantification method for therapeutic drug monitoring of FK506 in patients with COVID-19 using UHPLC-MS/MS with protein precipitation. We found that NMV increased FK506 blood concentration 10-fold. Therefore, it is necessary to re-consider co-administration of FK506 with NMV.

[Clinical characteristics of 16 neonates infected with SARS-CoV-2 during Omicron variant outbreak].

Objective: To analyze the clinical characteristics of the neonates infected with SARS-CoV-2 during the Omicron outbreak in Shanghai 2022. Methods: In this retrospective case series study, all the 16 neonates with SARS-CoV-2 Omicron infection who were admitted to the neonatal unit in Shanghai Public Health Clinical Center from March 1st to May 31st, 2022 were enrolled. Their epidemiological history, clinical manifestations, nucleic acid cycle threshold (Ct) value and outcomes were analyzed. Based on maternal vaccination, they were divided into vaccinated group and unvaccinated group. Rank sum test and Chi-square test were used for the comparison between the groups. Results: Among the 16 neonates, 10 were male, and 6 were female. All the infants were full-term. The infection was confirmed at the age of 12.5 (8.0, 20.5) days. All the neonates had a history of exposure to infected family members, and thus horizontal transmission was the primary mode. Four infants were asymptomatic, 12 were symptomatic, and there were no severe or critical cases. The most common clinical manifestation was fever (11 cases), with the highest temperature of 38.1 (37.9, 38.3) ℃ and a course of 1-5 days. Other clinical manifestations included nasal obstruction (3 cases), runny nose (2 cases), cough (2 cases), poor feeding (2 cases), vomiting (1 case), and mild tachypnea (1 case). The complete blood counts of all neonates were within the normal range, and the C-reactive protein increased slightly in 1 infant. Chest imaging was performed in 2 infants, showing mild focal exudative changes. Nucleic acid turned negative (Ct value ≥35) within 7-15 days after diagnosis. All neonates fully recovered after supportive treatment, and the length of hospitalization was 13 (10, 14) days. In the telephone follow-up 2 weeks after discharge for all 16 cases, no infant showed reoccurrence of clinical manifestations or nucleic acid reactivation. Maternal vaccination was not significantly correlated with symptomatic infection or the persistence of positive nucleic acid result in neonates (all P>0.05). Conclusions: Horizontal transmission is the primary mode for neonatal SARS-CoV-2 Omicron infection. Neonatal infections are usually mild or asymptomatic, with good short-term outcomes. And their clinical manifestations and laboratory examinations are nonspecific.

[Management and short-term outcomes of neonates born to mothers infected with SARS-CoV-2 Omicron variant].

Objective: To summarize the management and short-term outcomes of neonates delivered by mothers infected with SARS-CoV-2 Omicron variant. Methods: A retrospective study was performed on 158 neonates born to mothers infected with SARS-CoV-2 Omicron variant admitted to the isolation ward of Children's Hospital of Fudan University from March 15th, 2022 to May 30th, 2022. The postnatal infection control measures for these neonates, and their clinical characteristics and short-term outcomes were analyzed. They were divided into maternal symptomatic group and maternal asymptomatic group according to whether their mothers had SARS-CoV-2 symptoms. The clinical outcomes were compared between the 2 groups using Rank sum test and Chi-square test. Results: All neonates were under strict infection control measures at birth and after birth. Of the 158 neonates, 75 (47.5%) were male. The gestational age was (38+3±1+3) weeks and the birth weight was (3 201±463)g. Of the neonates included, ten were preterm (6.3%) and the minimum gestational age was 30+1 weeks. Six neonates (3.8%) had respiratory difficulty and 4 of them were premature and required mechanical ventilation. All 158 neonates were tested negative for SARS-COV-2 nucleic acid by daily nasal swabs for the first 7 days. A total of 156 mothers (2 cases of twin pregnancy) infected with SARS-CoV-2 Omicron variant, the time from confirmed SARS-CoV-2 infection to delivery was 7 (3, 12) days. Among them, 88 cases (56.4%) showed clinical symptoms, but none needed intensive care treatment. The peripheral white blood cell count of the neonates in maternal symptomatic group was significantly higher than that in maternal symptomatic group (23.0 (18.7, 28.0) × 109 vs. 19.6 (15.4, 36.6) × 109/L, Z=2.44, P<0.05). Conclusions: Neonates of mothers infected with SARS-CoV-2 Omicron variant during third trimester have benign short-term outcomes, without intrauterine infection through vertical transmission. Strict infection control measures at birth and after birth can effectively protect these neonates from SARS-CoV-2 infection.