SARS-CoV-2 late shedding may be infectious between immunocompromised hosts

Whole-genome sequencing to investigate transmission of SARS-CoV-2 in the acute healthcare setting: a systematic review

BACKGROUND

Whole-genome sequencing (WGS) has been used widely to elucidate transmission of SARS-CoV-2 in acute healthcare settings, and to guide infection, prevention, and control (IPC) responses.

AIM

To systematically appraise available literature, published between January 1st, 2020 and June 30th, 2022, describing the implementation of WGS in acute healthcare settings to characterize nosocomial SARS-CoV-2 transmission.

METHODS

Searches of the PubMed, Embase, Ovid MEDLINE, EBSCO MEDLINE, and Cochrane Library databases identified studies in English reporting the use of WGS to investigate SARS-CoV-2 transmission in acute healthcare environments. Publications involved data collected up to December 31st, 2021, and findings were reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.

FINDINGS

In all, 3088 non-duplicate records were retrieved; 97 met inclusion criteria, involving 62 outbreak analyses and 35 genomic surveillance studies. No publications from low-income countries were identified. In 87/97 (90%), WGS supported hypotheses for nosocomial transmission, while in 46 out of 97 (47%) suspected transmission events were excluded. An IPC intervention was attributed to the use of WGS in 18 out of 97 (18%); however, only three (3%) studies reported turnaround times ≤7 days facilitating near real-time IPC action, and none reported an impact on the incidence of nosocomial COVID-19 attributable to WGS.

CONCLUSION

WGS can elucidate transmission of SARS-CoV-2 in acute healthcare settings to enhance epidemiological investigations. However, evidence was not identified to support sequencing as an intervention to reduce the incidence of SARS-CoV-2 in hospital or to alter the trajectory of active outbreaks.

Casirivimab/Imdevimab for Active COVID-19 Pneumonia Which Persisted for Nine Months in a Patient with Follicular Lymphoma during Anti-CD20 Therapy

Immunocompromised patients are more likely to develop severe COVID-19, and exhibit high mortality. It is also hypothesized that chronic infection in these patients can be a risk factor for developing new variants. We describe a patient with prolonged active infection of COVID-19 who became infected during treatment with an anti-CD20 antibody (obinutuzumab) for follicular lymphoma. This patient had persistent RT-PCR positivity and live virus isolation for nine months despite treatment with remdesivir and other potential antiviral therapies. The computed tomography image of the chest showed that the viral pneumonia repeatedly appeared and disappeared in different lobes, as if a new infection had occurred continuously. The patient's SARS-CoV-2 antibody titer was negative throughout the illness, even after two doses of the BNT162b2 mRNA vaccine were administered in the seventh month of infection. A combination of monoclonal antibody therapy against COVID-19 (casirivimab and imdevimab) and antivirals resulted in negative RT-PCR results, and the virus was no longer isolated. The patient was clinically cured. During the 9-month active infection period, no fixed mutations in the spike (S) protein were detected, and the in vitro susceptibility to remdesivir was retained. Therapeutic administration of anti-SARS-CoV-2 monoclonal antibodies is essential in immunocompromised patients. Therefore, measures to prevent resistance against these key drugs are urgently needed.

Modular nanoarray vaccine for SARS-CoV-2

The current vaccine development strategies for the COVID-19 pandemic utilize whole inactive or attenuated viruses, virus-like particles, recombinant proteins, and antigen-coding DNA and mRNA with various delivery strategies. While highly effective, these vaccine development strategies are time-consuming and often do not provide reliable protection for immunocompromised individuals, young children, and pregnant women. Here, we propose a novel modular vaccine platform to address these shortcomings using chemically synthesized peptides identified based on the validated bioinformatic data about the target. The vaccine is based on the rational design of an immunogen containing two defined B-cell epitopes from the spike glycoprotein of SARS-CoV-2 and the universal T-helper epitope PADRE. The epitopes were conjugated to short DNA probes and combined with a complementary scaffold strand, resulting in sequence-specific self-assembly. The immunogens were then formulated by conjugation to gold nanoparticles by three methods or by co-crystallization with epsilon inulin. BALB/C mice were immunized with each formulation, and the IgG immune responses and virus neutralizing titers were compared. The results demonstrate that this assembly is immunogenic and generates neutralizing antibodies against wildtype SARS-CoV-2 and the Delta variant.

Update on COVID-19 Therapeutics for Solid Organ Transplant Recipients, Including the Omicron Surge

Major changes have occurred in therapeutics for coronavirus-19 (COVID-19) infection over the past 12-18 mo, most notably in early outpatient therapy. In most cases, solid organ transplant recipients were not included in the original clinical trials of these agents, so studies of real-world outcomes have been important in building our understanding of their utility. This review examines what is known about clinical outcomes in solid organ transplant recipients with newer therapies. SARS-CoV-2 monoclonal antibodies for early treatment or prophylaxis have likely prevented many hospitalizations and deaths. In addition, convalescent plasma, the oral drugs nirmatrelvir/ritonavir and molnupiravir, remdesivir for early outpatient treatment, anti-inflammatory therapy, and investigational virus-specific T-cell therapy will be discussed. Finally, the later consequences of COVID-19, such as secondary infections, long COVID symptoms, and persistent active infection, are identified as areas for future research.

Severe acute respiratory syndrome coronavirus 2 infection in the stem cell transplant recipient - clinical spectrum and outcome

PURPOSE OF REVIEW

Focusing on large multicenter cohorts reported over the last months, this review aims at summarizing the available evidence by July 2021 on the impact of coronavirus disease 2019 (COVID-19) on hematopoietic stem cell transplant (HSCT) recipients in terms of epidemiology, clinical features, and outcome.

RECENT FINDINGS

The incidence of COVID-19 in institutional cohorts varied according to different regions and study periods from 0.4% to 8.3%. Clinical presentation was overall comparable to other immunocompromised hosts and the general population. Microbiologically confirmed superinfection occurred in 13-25% of recipients, with most episodes due to hospital-acquired bacteria and few reported cases of COVID-19-associated aspergillosis. Prolonged nasopharyngeal severe acute respiratory syndrome coronavirus 2 shedding has been demonstrated for as long as 210 days. Mortality rates were similar across studies (14.8-28.4%) and did not markedly differ from those observed in nontransplant hematological patients during the first wave. Older age and shorter time from transplantation were associated with mortality, as well as underlying disease status and amount of immunosuppression. No outcome differences were found in most studies between allogeneic and autologous procedures.

SUMMARY

Considerable advances have been achieved in the characterization of COVID-19 in the HSCT population, although uncertainties remain in the optimal therapeutic management.