key: cord-1025391-uxsisab9
authors: Harte, Jeffrey; Hamzah, Lisa
title: COVID-19: management and infection control
date: 2021-09-24
journal: Medicine (Abingdon)
DOI: 10.1016/j.mpmed.2021.09.014
sha: 7ea6e270802b8c844e2d5e10a3d7de48bddd0e7c
doc_id: 1025391
cord_uid: uxsisab9

The coronavirus disease 2019 (COVID-19) pandemic has caused >4.5 million deaths worldwide to date. The emergence of the novel severe acute respiratory syndrome coronavirus 2 has created immense pressure on health services and complex challenges in public health. Essential features in managing COVID-19 include best-practice care for the individual but also minimizing exposure to uninfected patients, staff and the wider community. The central tenets in limiting disease transmission involves strict infection and prevention control, categorizing COVID-19 cases as possible, probable or confirmed, alongside contact tracing, isolation, hand hygiene and droplet precautions.

Coronavirus disease 2019 (COVID-19) has caused >4.5 million deaths worldwide to date. It is a multisystem, primarily respiratory disease caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Risk factors for severe disease include increasing age, diabetes, hypertension, cardiovascular disease, male gender and obesity 1 .

SARS-CoV-2 is an enveloped virus coated with membrane proteins and spike glycoproteins. The spike protein is responsible for host cell binding and cell entry via angiotensin-converting enzyme 2 (ACE2) receptors. The incubation period is approximately 5-6 days but can be up to 14 days. SARS-CoV-2 viral load peaks within the first week of illness, around 1-2 days before symptom onset. SARS-CoV-2 antibody concentrations are usually detectable by day 14. Virus yield in culture approaches zero at 10 days after symptom onset in mild cases 2 .

Initial symptoms during viral replication include fever, dry cough, dysgeusia, anosmia, myalgia, headache and diarrhoea. By day 10-14, as viral replication declines, the host inflammatory response phase predominate and a proportion of patients develop pneumonitis, presenting with tachypnoea, hypoxia, pyrexia and fine end-expiratory bi-basal crackles. 10-15% developing severe illness with elevated inflammatory markers, progressive interstitial inflammation and multiorgan involvement. Be wary of 'silent hypoxia', a phenomenon where patients feel clinically well with disproportionately low oxygen saturations (SpO 2 ); this is usually a 'red flag' for impending acute respiratory failure.

Asymptomatic or mild disease (80% of cases) may be managed at home with simple analgesia. Individuals should be advised on symptoms of worsening disease and when to seek clinical advice; the use of pulse oximeters in the community has been useful in recognizing moderate to severe disease 1 .

Severe disease is defined as having clinical signs of pneumonitis plus one of the following: >30 breaths per minute, severe respiratory distress or an SpO 2 <90% on room air. These individuals require hospital admission. In addition to a nasopharyngeal SARS-CoV-2 polymerase chain reaction (PCR) test, recommended baseline investigations include a full blood count, metabolic panel, inflammatory markers including C-reactive protein (CRP), ferritin, lactate dehydrogenase, cardiac biomarkers, D-dimer, prothrombin time and arterial blood gas. Blood/sputum cultures and serum procalcitonin may identify bacterial co-infection. A chest X-ray should be performed to look for unilateral or bilateral infiltrates, seen in 25% and 75% of cases, respectively (Figure 1) 1 .

Supplemental oxygen should be used to maintain an SpO 2 of 92-95%. Awake prone positioning increases recruitment of alveoli and may improve oxygenation in patients with increasing oxygen requirements. Intravenous fluids may be required to maintain euvolaemia. Venous thromboembolism prophylaxis is recommended; enhanced prophylaxis or treatment dose low molecular weight heparin may be considered because of the increased risk of thrombosis 2 . Antibiotics are only indicated for suspected bacterial co-infection based on features such as a productive cough, neutrophilia or radiological findings. 1 

Targeted treatment for COVID-19 is offered to all hospitalized patients requiring oxygen. Dexamethasone was associated with an 18% reduction in mortality in the RECOVERY (Randomised Evaluation of COVID-19 Therapy) trial (36% in those invasively ventilated) 2 . Tocilizumab demonstrated a mortality benefit and is offered in addition to those with a CRP >75 mg/L and no evidence of bacterial co-infection. Remdesivir, an antiviral agent, may shorten recovery time if provided within 10 days of symptom. 2 Ceiling of care All admissions should have a frailty assessment (using the Clinical Frailty Score (CFS) if >65 years and a treatment escalation plan should be discussed. 2 Studies in COVID-19 demonstrate a 12% increase in mortality for every 1-point increase in CFS 1 . Outcomes of cardiopulmonary arrest in COVID-19 are poor with one study demonstrating only 7% of patients survived to 29 days with normal or mildly impaired neurological status (decreasing to 3% in those aged ≥80 years). 1 uses chimpanzee adenovirus DNA as a viral vector, engineered to contain code for the spike protein and, unlike mRNA vaccines, can be stored using standard refrigeration. All vaccines convey up to 95% protection against progression to severe COVID-19. Research determining whether variants are associated with decreased immunogenicity is continuing 2 .

Possible cases are defined as any person with one or more of the following: fever, cough, dyspnoea, new anosmia or dysgeusia. Probable cases are individuals with radiological evidence compatible with COVID-19 or a possible case who has been residing/working in an area with high transmission rates of COVID-19 or had close contact with a confirmed case in the 14 days before symptom onset 1 .

Confirmed cases are those with a confirmed PCR test. Contacts are individuals who have been directly in contact with a confirmed case (within one metre of someone infected with SARS-CoV-2 for at least 15 minutes), regardless of whether they were symptomatic at the time.

Current guidance for patients with confirmed symptomatic or asymptomatic SARS-CoV-2 in the community is self-isolation for 10 days (symptoms must have resolved for 24 hours before completing isolation). Unvaccinated contacts of a confirmed case must quarantine for 10 days and undergo testing if they become symptomatic. Individuals admitted to hospital require 14 days' isolation 3 . In hospital, confirmed, possible or probable cases and those awaiting PCR test results should be isolated with similar cases or in side rooms. Outbreaks in healthcare settings are challenging and require strict contact tracing, isolation measures and regular outbreak control meetings.

Infection control measures are as per any droplet spread infectious disease. Strict hand hygiene, use of gloves, aprons, and surgical masks covering the chin, mouth and nose, physical distancing and keeping areas well ventilated are essential in preventing viral transmission. In an environment with aerosol-generating procedures such as invasive or non-invasive ventilation, more specific respiratory precautions should be taken, including FFP3 masks. 

COVID-19 rapid guideline: managing COVID-19

World Health Organization. WHO Coronavirus Disease (COVID-19) Dashboard. 2