Antibody escape, the risk of serotype formation, and rapid immune waning: Modeling the implications of SARS-CoV-2 immune evasion.

As the COVID-19 pandemic progresses, widespread community transmission of SARS-CoV-2 has ushered in a volatile era of viral immune evasion rather than the much-heralded stability of "endemicity" or "herd immunity." At this point, an array of viral strains has rendered essentially all monoclonal antibody therapeutics obsolete and strongly undermined the impact of vaccinal immunity on SARS-CoV-2 transmission. In this work, we demonstrate that antibody escape resulting in evasion of pre-existing immunity is highly evolutionarily favored and likely to cause waves of short-term transmission. In the long-term, invading strains that induce weak cross-immunity against pre-existing strains may co-circulate with those pre-existing strains. This would result in the formation of serotypes that increase disease burden, complicate SARS-CoV-2 control, and raise the potential for increases in viral virulence. Less durable immunity does not drive positive selection as a trait, but such strains may transmit at high levels if they establish. Overall, our results draw attention to the importance of inter-strain cross-immunity as a driver of transmission trends and the importance of early immune evasion data to predict the trajectory of the pandemic.

Custom Mega Prosthesis in a Rare case of Epithelioid Hemangioendothelioma of Proximal Tibia - A Case Report.

Introduction: Lytic lesions of the proximal tibia include a plethora of differential diagnoses. The most common ones are the Giant cell tumor, fibrous dysplasia, adamantinoma, chondromyxoid fibroma, and osteoblastoma. The rarer ones include vascular tumors such as hemangioma and hemangioendothelioma. A systematic line of investigations is essential to pick up the right diagnosis especially in case of rarer conditions. In this background, we present a case of lytic lesion of the proximal tibia which turned out to be epitheloid hemangioendothelioma (EHE). Case Report: A 37-year-old female presented with pain and swelling in the left knee for 2 years. On examination, the patient had a 3 × 4 cm firm, non-tender, and well-defined swelling on the anterolateral aspect of the proximal tibia. X-ray showed a lytic lesion of the proximal tibia. Magnetic resonance imaging was suggestive of a giant cell tumor. However, the biopsy revealed a rare diagnosis of epithelioid hemangioendothelioma. Conclusion: The patient was managed with wide excision. In a young adult, arthrodesis may not be the best option; hence, we reconstructed the joint with a custom mega prosthesis (CMP). At 3 years follow-up, our patient had no signs of recurrence. To our best knowledge, this is the first report on the use of CMP in a case of EHE.

Novel Multimodal Treatment Regimen for the Management of Primary Sacrococcygeal Cystic Echinococcosis.

Introduction: Osseous hydatidosis is a rare condition most commonly involving the spine. Among spinal segments, sacrococcygeal involvement is even rarer. Moreover, the lesion is more prone to recurrence owing to the infiltrative nature of microvesicular lesions involving the spine. In this case report, we describe an effective multimodal management approach toward the management of primary sacrococcygeal cystic echinococcosis. Case Report: A 56-year-old female presented with complaints of severe back pain and urinary incontinence for 3 months. She presented with a slow-onset cauda equina syndrome with radiating pain to both lower limbs. Radiographic evaluation showed an expansile lytic lesion affecting the right iliac wing with near-complete cortical bone destruction of the sacrum. Magnetic resonance imaging revealed neural involvement with sacral destruction by a multiloculated cystic mass, extending to the spinal canal. No coexisting lesions were noted anywhere. Echinococcosis was diagnosed with serum enzyme-linked immunosorbent assay. She underwent neoadjuvant therapy with albendazole and praziquantel, followed by ultrasound-guided percutaneous aspiration injection and reaspiration (PAIR) with hypertonic saline followed by sclerosant (95% ethyl alcohol) into the residual cyst cavity. Later, she open excision of the residual multiloculated cystic mass was performed. Adjuvant medical therapy was continued for 3 months post-surgery. The patient regained her neurological functions by 6 months without any residual sequelae or symptomatic recurrence until 4 years of follow-up. Conclusion: Multimodal treatment regimen comprising of oral medical therapy by albendazole and praziquantel along with PAIR and surgical in toto excision of the cyst followed by post-operative oral medical therapy for 3 months has given excellent results in sacrococcygeal cystic echinococcosis.

Recurrence-free management of type 2 variant of giant cell tumour of extensor tendon sheath of thumb.

A 30-year-old woman presented with swelling in her right thumb of 3-month duration which was slow-growing in nature without a history of trauma. On examination, firm non-tender swelling with ill-defined border over the dorsomedial aspect of the first metacarpal was noted. The swelling was mobile only in the vertical plane with restricted adduction and abduction. Plain X-ray revealed mild erosion of the first metacarpal head. Diagnostic ultrasound confirmed the lesion to arise from the extensor tendon sheath of diffuse type without any bony involvement. A wide local excision biopsy of the swelling was planned. Intraoperatively, a 3×2 cm greyish-white mass, bony hard in consistency with lobulated surface was found arising from the tendon sheath of the extensor tendon of the thumb; it was completely excised with a wide margin. Histopathological examination revealed polyhedral cells admixed with osteoclastic type giant cells. Biopsy from the first metatarsal was normal. The patient is on follow-up for the last 5 years with no evidence of recurrence.

Mental Health in High School Students at the Time of COVID-19: A Student's Perspective.

The global impact of 2019 novel coronavirus disease (COVID-19) is unprecedented and has left countries grappling with uncertainties. Various public health measures all over the world have been implemented to reduce associated illness severity and mortality. Countries are now coming out of lockdown with cautious optimism after successfully flattening the curve with measures such as social distancing, quarantine, and closure of public places including schools. However, the challenges related to the impact on students' mental health continue beyond this phase of the pandemic. This article highlights key issues and offers practical solutions to address the mental health of adolescents during the COVID-19 pandemic from a high school student's perspective.