COVID-19 resources: Overview

Researchers are racing to determine whether a fast-spreading coronavirus variant poses a threat to COVID vaccines’ effectiveness.

The continuing spread of SARS-CoV-2 remains a Public Health Emergency of International Concern. What physicians need to know about transmission, diagnosis, and treatment of Covid-19 is the subject of ongoing updates from infectious disease experts at the Journal.
In this audio interview conducted on November 29, 2021, the editors are joined by South African researcher Salim Abdool Karim to discuss the omicron variant recently identified in southern Africa.

Early lab results suggest that existing vaccines could be less effective against the fast-spreading coronavirus variant, but boosters should improve immunity.

Abstract
The latest severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant Omicron (B.1.1.529) has ushered panic responses around the world due to its contagious and vaccine escape mutations. The essential infectivity and antibody resistance of the SARS-CoV-2 variant are determined by its mutations on the spike (S) protein receptor-binding domain (RBD). However, a complete experimental evaluation of Omicron might take weeks or even months. Here, we present a comprehensive quantitative analysis of Omicron's infectivity, vaccine-breakthrough, and antibody resistance. An artificial intelligence (AI) model, which has been trained with tens of thousands of experimental data points and extensively validated by experimental data on SARS-CoV-2, reveals that Omicron may be over ten times more contagious than the original virus or about twice as infectious as the Delta variant. Based on 132 three-dimensional (3D) structures of antibody-RBD complexes, we unveil that Omicron may be twice more likely to escape current vaccines than the Delta variant. The Food and Drug Administration (FDA)-approved monoclonal antibodies (mAbs) from Eli Lilly may be seriously compromised. Omicron may also diminish the efficacy of mAbs from Celltrion and Rockefeller University. However, its impact on Regeneron mAb cocktail appears to be mild.

Abstract
Importance: Assessing COVID-19 vaccine performance against the rapidly spreading SARS-CoV-2 Omicron variant is critical to inform public health guidance.

Objective: To estimate the association between receipt of 3 doses of Pfizer-BioNTech BNT162b2 or Moderna mRNA-1273 vaccine and symptomatic SARS-CoV-2 infection, stratified by variant (Omicron and Delta).

Design, setting, and participants: A test-negative case-control analysis among adults 18 years or older with COVID-like illness tested December 10, 2021, through January 1, 2022, by a national pharmacy-based testing program (4666 COVID-19 testing sites across 49 US states).

Exposures: Three doses of mRNA COVID-19 vaccine (third dose ≥14 days before test and ≥6 months after second dose) vs unvaccinated and vs 2 doses 6 months or more before test (ie, eligible for a booster dose).

Main outcomes and measures: Association between symptomatic SARS-CoV-2 infection (stratified by Omicron or Delta variants defined using S-gene target failure) and vaccination (3 doses vs unvaccinated and 3 doses vs 2 doses). Associations were measured with multivariable multinomial regression. Among cases, a secondary outcome was median cycle threshold values (inversely proportional to the amount of target nucleic acid present) for 3 viral genes, stratified by variant and vaccination status.

Results: Overall, 23 391 cases (13 098 Omicron; 10 293 Delta) and 46 764 controls were included (mean age, 40.3 [SD, 15.6] years; 42 050 [60.1%] women). Prior receipt of 3 mRNA vaccine doses was reported for 18.6% (n = 2441) of Omicron cases, 6.6% (n = 679) of Delta cases, and 39.7% (n = 18 587) of controls; prior receipt of 2 mRNA vaccine doses was reported for 55.3% (n = 7245), 44.4% (n = 4570), and 41.6% (n = 19 456), respectively; and being unvaccinated was reported for 26.0% (n = 3412), 49.0% (n = 5044), and 18.6% (n = 8721), respectively. The adjusted odds ratio for 3 doses vs unvaccinated was 0.33 (95% CI, 0.31-0.35) for Omicron and 0.065 (95% CI, 0.059-0.071) for Delta; for 3 vaccine doses vs 2 doses the adjusted odds ratio was 0.34 (95% CI, 0.32-0.36) for Omicron and 0.16 (95% CI, 0.14-0.17) for Delta. Median cycle threshold values were significantly higher in cases with 3 doses vs 2 doses for both Omicron and Delta (Omicron N gene: 19.35 vs 18.52; Omicron ORF1ab gene: 19.25 vs 18.40; Delta N gene: 19.07 vs 17.52; Delta ORF1ab gene: 18.70 vs 17.28; Delta S gene: 23.62 vs 20.24).

Conclusions and relevance: Among individuals seeking testing for COVID-like illness in the US in December 2021, receipt of 3 doses of mRNA COVID-19 vaccine (compared with unvaccinated and with receipt of 2 doses) was less likely among cases with symptomatic SARS-CoV-2 infection compared with test-negative controls. These findings suggest that receipt of 3 doses of mRNA vaccine, relative to being unvaccinated and to receipt of 2 doses, was associated with protection against both the Omicron and Delta variants, although the higher odds ratios for Omicron suggest less protection for Omicron than for Delta.

Abstract.
The coronavirus disease 2019 (COVID-19) outbreak has been designated a public health emergency of international concern. To prepare for a pandemic, hospitals need a strategy to manage their space, staff, and supplies so that optimum care is provided to patients. In addition, infection prevention measures need to be implemented to reduce in-hospital transmission. In the operating room, these preparations involve multiple stakeholders and can present a significant challenge. Here, we describe the outbreak response measures of the anesthetic department staffing the largest (1,700-bed) academic tertiary level acute care hospital in Singapore (Singapore General Hospital) and a smaller regional hospital (Sengkang General Hospital). These include engineering controls such as identification and preparation of an isolation operating room, administrative measures such as modification of workflow and processes, introduction of personal protective equipment for staff, and formulation of clinical guidelines for anesthetic management. Simulation was valuable in evaluating the feasibility of new operating room set-ups or workflow. We also discuss how the hierarchy of controls can be used as a framework to plan the necessary measures during each phase of a pandemic, and review the evidence for the measures taken. These containment measures are necessary to optimize the quality of care provided to COVID-19 patients and to reduce the risk of viral transmission to other patients or healthcare workers.

Abstract.
A global health emergency has been declared by the World Health Organization as the 2019-nCoV outbreak spreads across the world, with confirmed patients in Canada. Patients infected with 2019-nCoV are at risk for developing respiratory failure and requiring admission to critical care units. While providing optimal treatment for these patients, careful execution of infection control measures is necessary to prevent nosocomial transmission to other patients and to healthcare workers providing care. Although the exact mechanisms of transmission are currently unclear, human-to-human transmission can occur, and the risk of airborne spread during aerosol-generating medical procedures remains a concern in specific circumstances. This paper summarizes important considerations regarding patient screening, environmental controls, personal protective equipment, resuscitation measures (including intubation), and critical care unit operations planning as we prepare for the possibility of new imported cases or local outbreaks of 2019-nCoV. Although understanding of the 2019-nCoV virus is evolving, lessons learned from prior infectious disease challenges such as Severe Acute Respiratory Syndrome will hopefully improve our state of readiness regardless of the number of cases we eventually manage in Canada.

By January 7, 2020, Chinese scientists confirmed that the outbreak was caused by a novel coronavirus, initially referred to as the 2019-nCoV,2 and recently renamed as severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2), and the disease is now termed coronavirus disease 2019 (COVID-19) by the WHO. As of February 20, 2020, more than 75,748 confirmed cases of COVID-19 have been reported in 28 countries (including China) and international conveyance (cruise ship in the Japanese territorial waters), with approximately 99% of cases occurring in mainland China.