Broad SARS-CoV-2 spike-specific CD4+ T-cell response preserves recognition of variants of concern (preprint)

CD4 + T-cells are essential for protection against viruses including SARS-CoV-2. Mutations in SARS-CoV-2 variants of concern (VOC) can enhance infectivity and reduce antibody recognition. CD4 + T-cell sensitivity to mutations is less well understood because few epitopes have been mapped. Characterising > 100 SARS-CoV-2-specific CD4 + T-cell clones from convalescent healthcare workers, we mapped and HLAII restricted 21 epitopes across three viral proteins. Responses to the same spike epitopes were also present after vaccination of uninfected individuals. Lack of CD4 + T-cell cross-reactivity with endemic beta-coronaviruses suggests these responses arose from naïve T-cells rather than pre-existing cross-reactive coronavirus-specific T-cell responses. 10/17 spike epitopes were mutated in VOCs and CD4 + T-cell recognition of 7 was impaired, including 3 of 4 epitopes mutated in Omicron. Broad CD4 + T-cell targeting of epitopes likely limits evasion by current VOCs. However, continued genomic surveillance is vital to identify new emerging mutations able to evade CD4 + T-cell immunity.

A Phase 2 Randomized, Double-Blind, Placebo-controlled Trial of Oral Camostat Mesylate for Early Treatment of COVID-19 Outpatients Showed Shorter Illness Course and Attenuation of Loss of Smell and Taste (preprint)

Importance: Early treatment of mild SARS-CoV-2 infection might lower the risk of clinical deterioration in COVID-19. Objective: To determine whether oral camostat mesylate would reduce upper respiratory SARS-CoV-2 viral load in newly diagnosed outpatients with mild COVID-19, and would lead to improvement in COVID-19 symptoms. Design: From June, 2020 to April, 2021, we conducted a randomized, double-blind, placebo-controlled phase 2 trial. Setting: Single site, academic medical center, outpatient setting in Connecticut, USA. Participants: Of 568 COVID-19 positive potential adult participants diagnosed within 3 days of study entry and assessed for eligibility, 70 were randomized and 498 were excluded (198 did not meet eligibility criteria, 37 were not interested, 265 were excluded for unknown or other reasons). The primary inclusion criteria were a positive SARS-CoV-2 nucleic acid amplification result in adults within 3 days of screening regardless of COVID-19 symptoms. Intervention: Treatment was 7 days of oral camostat mesylate, 200 mg po four times a day, or placebo. Main Outcomes and Measures: The primary outcome was reduction of 4-day log10 nasopharyngeal swab viral load by 0.5 log10 compared to placebo. The main prespecified secondary outcome was reduction in symptom scores as measured by a quantitative Likert scale instrument, Flu-PRO-Plus modified to measure changes in smell/taste measured using FLU-PRO-Plus. Results: Participants receiving camostat had statistically significant lower quantitative symptom scores (FLU-Pro-Plus) at day 6, accelerated overall symptom resolution and notably improved taste/smell, and fatigue beginning at onset of intervention in the camostat mesylate group compared to placebo. Intention-to-treat analysis demonstrated that camostat mesylate was not associated with a reduction in 4-day log10 NP viral load compared to placebo. Conclusions and relevance: The camostat group had more rapid resolution of COVID-19 symptoms and amelioration of the loss of taste and smell. Camostat compared to placebo was not associated with reduction in nasopharyngeal SARS-COV-2 viral load. Additional clinical trials are warranted to validate the role of camostat mesylate on SARS-CoV-2 infection in the treatment of mild COVID-19. Trial registration: Clinicaltrials.gov, NCT04353284 (04/20/20) (https://clinicaltrials.gov/ct2/show/NCT04353284?term=camostat+%2C+yale&draw=2&rank=1)

Colorectal cancer chemotherapy during COVID-19 pandemic

The management of patients with colorectal cancer during the current SARS-CoV2 pandemic opens a Pandora's Box. While the world is facing an unprecedented crisis of fighting a life-threatening infectious disease, patients with colorectal cancer are facing the dual challenge to fight cancer while protecting them from infection. We attempted to critically examine the existing evidence for chemotherapy in colorectal cancer in different stages of disease and suggest treatment options in these vulnerable patients. Treatment options which do not overburden existing health-care resources can be provided for patients with colorectal cancer patients requiring chemotherapy without significant compromise in efficacy or increase the risk of hospital acquired SAR-CoV-2 infection.