Diet Induced Obesity and Diabetes Enhance Mortality and Reduces Vaccine Efficacy for SARS-CoV-2

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), the causative agent of Coronavirus disease 2019 (COVID-19), emerged in Wuhan, China, in December 2019. As of October 2022, there have been over 625 million confirmed cases of COVID-19, including over 6.5 million deaths. Epidemiological studies have indicated that comorbidities of obesity and diabetes mellitus are associated with increased morbidity and mortality following SARS-CoV-2 infection. We determined how the comorbidities of obesity and diabetes affect morbidity and mortality following SARS-CoV-2 infection in unvaccinated and adjuvanted spike nanoparticle (NVX-CoV2373) vaccinated mice. We find that obese/diabetic mice infected with SARS-CoV-2 have increased morbidity and mortality compared to age matched normal mice. Mice fed a high-fat diet (HFD) then vaccinated with NVX-CoV2373 produce equivalent neutralizing antibody titers to those fed a normal diet (ND). However, the HFD mice have reduced viral clearance early in infection. Analysis of the inflammatory immune response in HFD mice demonstrates a recruitment of neutrophils that was correlated with increased mortality and reduced clearance of the virus. This model recapitulates the increased disease severity associated with obesity and diabetes in humans with COVID-19 and is an important comorbidity to study with increasing obesity and diabetes across the world.

Pyrimidine biosynthesis inhibitors synergize with nucleoside analogs to block SARS-CoV-2 infection

The ongoing COVID-19 pandemic has highlighted the dearth of approved drugs to treat viral infections, with only [~]90 FDA approved drugs against human viral pathogens. To identify drugs that can block SARS-CoV-2 replication, extensive drug screening to repurpose approved drugs is underway. Here, we screened [~]18,000 drugs for antiviral activity using live virus infection in human respiratory cells. Dose-response studies validate 122 drugs with antiviral activity and selectivity against SARS-CoV-2. Amongst these drug candidates are 16 nucleoside analogs, the largest category of clinically used antivirals. This included the antiviral Remdesivir approved for use in COVID-19, and the nucleoside Molnupirivir, which is undergoing clinical trials. RNA viruses rely on a high supply of nucleoside triphosphates from the host to efficiently replicate, and we identified a panel of host nucleoside biosynthesis inhibitors as antiviral, and we found that combining pyrimidine biosynthesis inhibitors with antiviral nucleoside analogs synergistically inhibits SARS-CoV-2 infection in vitro and in vivo suggesting a clinical path forward.

Immunogenicity and In vivo protection of a variant nanoparticle vaccine that confers broad protection against emerging SARS-CoV-2 variants

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) continues to spread globally. As SARS-CoV-2 has transmitted from person to person, variant viruses have emerged with elevated transmission rates and higher risk of infection for vaccinees. We present data showing that a recombinant prefusion-stabilized Spike (rS) protein based on the B.1.351 sequence (rS-B.1.351) was highly immunogenic in mice and produced neutralizing antibodies against SARS-CoV-2/WA1, B.1.1.7, and B.1.351. Mice vaccinated with our prototype vaccine NVX-CoV2373 (rS-WU1) or rS-B.1.351 alone, in combination, or as a heterologous prime boost, were protected when challenged with live SARS-CoV-2/B.1.1.7 or SARS-CoV-2/B.1.351. Virus titer was reduced to undetectable levels in the lungs post-challenge in all vaccinated mice, and Th1-skewed cellular responses were observed. A strong anamnestic response was demonstrated in baboons boosted with rS-B.1.351 approximately one year after immunization with NVX-CoV2373 (rS-WU1). An rS-B.1.351 vaccine alone or in combination with prototype rS-WU1 induced protective antibody- and cell-mediated responses that were protective against challenge with SARS-CoV-2 variant viruses.

Transmission of SARS-CoV-2 Lineage B.1.1.7 in England: Insights from linking epidemiological and genetic data

The SARS-CoV-2 lineage B.1.1.7, now designated Variant of Concern 202012/01 (VOC) by Public Health England, originated in the UK in late Summer to early Autumn 2020. We examine epidemiological evidence for this VOC having a transmission advantage from several perspectives. First, whole genome sequence data collected from community-based diagnostic testing provides an indication of changing prevalence of different genetic variants through time. Phylodynamic modelling additionally indicates that genetic diversity of this lineage has changed in a manner consistent with exponential growth. Second, we find that changes in VOC frequency inferred from genetic data correspond closely to changes inferred by S-gene target failures (SGTF) in community-based diagnostic PCR testing. Third, we examine growth trends in SGTF and non-SGTF case numbers at local area level across England, and show that the VOC has higher transmissibility than non-VOC lineages, even if the VOC has a different latent period or generation time. Available SGTF data indicate a shift in the age composition of reported cases, with a larger share of under 20 year olds among reported VOC than non-VOC cases. Fourth, we assess the association of VOC frequency with independent estimates of the overall SARS-CoV-2 reproduction number through time. Finally, we fit a semi-mechanistic model directly to local VOC and non-VOC case incidence to estimate the reproduction numbers over time for each. There is a consensus among all analyses that the VOC has a substantial transmission advantage, with the estimated difference in reproduction numbers between VOC and non-VOC ranging between 0.4 and 0.7, and the ratio of reproduction numbers varying between 1.4 and 1.8. We note that these estimates of transmission advantage apply to a period where high levels of social distancing were in place in England; extrapolation to other transmission contexts therefore requires caution.

COVID-19 epidemic severity is associated with timing of non-pharmaceutical interventions

Background: Unprecedented public health interventions including travel restrictions and national lockdowns have been implemented to stem the COVID-19 epidemic, but the effectiveness of non-pharmaceutical interventions is still debated. International comparisons are hampered by highly variable conditions under which epidemics spread and differences in the timing and scale of interventions. Cumulative COVID-19 morbidity and mortality are functions of both the rate of epidemic growth and the duration of uninhibited growth before interventions were implemented. Incomplete and sporadic testing during the early COVID-19 epidemic makes it difficult to identify how long SARS-CoV-2 was circulating in different places. SARS-CoV-2 genetic sequences can be analyzed to provide an estimate of both the time of epidemic origin and the rate of early epidemic growth in different settings. Methods: We carried out a phylogenetic analysis of more than 29,000 publicly available whole genome SARS-CoV-2 sequences from 57 locations to estimate the time that the epidemic originated in different places. These estimates were cross-referenced with dates of the most stringent interventions in each location as well as the number of cumulative COVID-19 deaths following maximum intervention. Phylodynamic methods were used to estimate the rate of early epidemic growth and proxy estimates of epidemic size. Findings: The time elapsed between epidemic origin and maximum intervention is strongly associated with different measures of epidemic severity and explains 46% of variance in numbers infected at time of maximum intervention. The reproduction number is independently associated with epidemic severity. In multivariable regression models, epidemic severity was not associated with census population size. The time elapsed between detection of initial COVID-19 cases to interventions was not associated with epidemic severity, indicating that many locations experienced long periods of cryptic transmission. Interpretation: Locations where strong non-pharmaceutical interventions were implemented earlier experienced much less severe COVID-19 morbidity and mortality during the period of study.

Evaluating the effects of SARS-CoV-2 Spike mutation D614G on transmissibility and pathogenicity

Global dispersal and increasing frequency of the SARS-CoV-2 Spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of Spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large data set, well represented by both Spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the Spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant.

Simultaneous bilateral breast reconstruction with superior gluteal artery perforator (SGAP) flaps.

The superior gluteal artery perforator (SGAP) flap is a useful technique for restoration of the breast after mastectomy. If appropriately planned, the soft-tissue envelope supplied by the superior gluteal artery perforator vessels can be harvested with minimal donor site morbidity and often results in a highly esthetic restoration of the breasts. Dissection of the flap is performed with complete preservation of gluteus maximus muscle function. The resulting vascular pedicle obtained via dissection through the muscle is longer than that of gluteal musculocutaneous flaps and affords the surgeon the luxury of avoiding vein grafts in the anastomotic phase of surgery. Despite these advantages, use of the SGAP flap is not popular among reconstructive surgeons. Many practitioners are not familiar with the vascular anatomy of the gluteal area and may not be comfortable with the dissection of the parent vessels or lack the desire to practice microsurgery. On the other hand, our group has reported the largest experience to date with this method of breast reconstruction and has found the SGAP flap to be a reliable and safe method of autologous breast restoration in unilateral absence of the breast. Although the indications to perform single-stage gluteal tissue transplantation for bilateral breast restoration are uncommon, they do occasionally arise in clinical practice. We have carried out concurrent bilateral breast reconstruction using SGAP flaps on 6 patients with acceptable overall morbidity. All flaps went on to survive and resulted in highly esthetic restorations of the breast. Though a challenging undertaking, in-unison transfer of bilateral SGAP flaps serves as a useful option for a subset of patients desiring 1-stage bilateral breast reconstruction.

The thoracodorsal artery perforator flap: clinical experience and anatomic study with emphasis on harvest techniques.

The thoracodorsal artery perforator flap is a relatively new flap that has yet to find its niche in reconstructive surgery. At the authors' institution it has been used for limb salvage, head and neck reconstruction, and trunk reconstruction in cases related to trauma, burns, and malignancy. The authors have found the flap to be advantageous for cranial base reconstruction and for resurfacing the face and oral cavity. The flap has been used successfully for reconstruction of traumatic upper and lower extremity defects, and it can be used as a pedicled flap or as a free tissue transfer. The perforating branches of the thoracodorsal artery offer a robust blood supply to a skin-soft-tissue paddle of 10 to 12 cm x 25 cm, overlying the latissimus dorsi muscle. The average pedicle length is 20 cm (range, 16 to 23 cm), which allows for a safe anastomosis outside the zone of injury in traumatized extremities; the flap can be made sensate by neurorrhaphy with sensory branches of the intercostal nerves. Vascularized bone can be transferred with this flap by taking advantage of the inherent vascular anatomy of the subscapular artery. A total of 30 pedicled and free flap transfers were performed at the authors' institution with an overall complication rate of 23 percent and an overall flap survival rate of 97 percent. Major complications, such as vascular thrombosis, return to the operating room, fistula formation, recurrence of tumor, and flap loss, occurred in 17 percent of the patients. Despite these drawbacks, the authors have found the thoracodorsal artery perforator flap to be a safe and extremely versatile flap that offers significant advantages in acute and delayed reconstruction cases.

Bilateral breast reconstruction with the deep inferior epigastric perforator (DIEP) flap: an experience with 280 flaps.

Bilateral prophylactic mastectomy can reduce the incidence of breast cancer by 87 to 93% in high-risk individuals and is an appealing option for many patients if reconstruction can be provided with acceptable morbidity and outstanding esthetic results. Autogenous breast reconstruction techniques have evolved over the last 20 years to meet this goal. Familiarity with the deep inferior epigastric perforator (DIEP) flap led us to carry out simultaneous bilateral breast reconstruction with acceptable morbidity and superior esthetic outcome in 3 patient groups: (1) after bilateral prophylactic mastectomy, (2) after therapeutic and contralateral prophylactic mastectomy, and (3) after explantation of bilateral implant failures. A retrospective review of our experience with 280 flaps in 140 patients was performed. Average operating times, including time for implant removal or mastectomy and reconstruction, was 7.3 hours. Average hospitalization was 3.9 days. Significant perioperative complications occurred in 9 patients (6.4%); all returned to the operating room. This included 7 microvascular complications, 1 hematoma, 1 seroma, and 1 DVT. Less significant complications were divided into early and late. The early complications included 1.8% partial flap necrosis, 4.2% abdominal apron necrosis greater than 5 cm2, 2.9% seromas that required intervention, and 5.7% partial breast flap dehiscence. Late complications included 12.5% fat necrosis of any size and 2.1% hernia formation. Smoking, obesity, age, history of chest wall radiation, and flap size were evaluated as risk factors for increased morbidity.

Breast reconstruction with gluteal artery perforator (GAP) flaps: a critical analysis of 142 cases.

Fujino was the first to introduce gluteal tissue as a free flap for breast reconstruction. The use of the musculocutaneous flap from the buttock in breast reconstruction has been championed by Shaw. Despite the initial enthusiasm for this area as a donor site, few other large series exist on the subject. Two decades of experience with this region as a donor site led to recognition of advantages and drawbacks. Furthermore, use of both the superior and inferior gluteal musculocutaneous flap was associated with certain important donor site complications and the use of vein grafts to allow for microvascular anastomosis. The evolution of free tissue transfer has progressed to the level of the perforator flap. This reconstructive technique allows elevation of tissue from any region consisting only of fat and skin. This minimizes donor site morbidity by allowing preservation of the underlying muscle and coverage of important structures in the region such as nerves. The superior and inferior gluteal perforator flaps have been used at our institution for breast reconstruction since 1993. The superior gluteal artery perforator (S-GAP) flap is our preferred method of breast reconstruction when the abdomen is not available or preferable. We report the result of this flap over the past 9 years and point out important surgical refinements, advantages, disadvantages, and lessons learned during this time.

New technique for nipple areola reconstruction: arrow flap and rib cartilage graft for long-lasting nipple projection.

The nipple-areola complex is an integral part of breast reconstruction. It serves as an important landmark for the new breast and many techniques have been described for its reconstruction. Historically, nipple projection has been most difficult to achieve and maintain. The authors found that techniques that use isolated soft tissue flaps eventually fail secondary to scar contraction with loss of projection. Since 1994, the authors have used a local skin fat flap shaped as an arrow for the reconstruction of the nipple on 454 breasts. The arrow shape is advantageous because it allows the scar to be broken on closure, minimizing postoperative wound contracture. Within the flap, the authors routinely use a rib cartilage graft, which provides additional support and projection for the skin-soft-tissue envelope. The graft is harvested during the initial breast flap transfer for the purpose of exposing the internal mammary vessels and has been obtained without any additional morbidity. By combining a skin fat flap and rib cartilage graft, the authors have achieved excellent long-term projection and a more esthetically pleasing nipple reconstruction.