Covid-19

Descriptive text is not available for this imageBASICS

DESCRIPTION

  • Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly communicable and pathogenic coronavirus causing an acute respiratory disease known as coronavirus 2019 (COVID-19).
  • The novel coronavirus originated in early December 2019 and spread rapidly worldwide, leading to one of the deadliest pandemics in human history.
  • Genetic lineages of SARS-CoV-2 have been emerging and circulating around the world since the beginning of the COVID-19 pandemic with varying degrees of infectivity and virulence.
  • Alpha and Delta variants were followed by Omicron variants, such that by 2022, the Omicron subvariants of COVID-19 (e.g., BA.5) are the dominant strains of the virus.
  • The origin of SARS-CoV-2 has not been identified. A zoonotic origin has been proposed as genetic sequencing of SARS-CoV-2 has revealed similarities to bat coronaviruses.

EPIDEMIOLOGY

  • SARS-CoV-2 is primarily spread by exhaled respiratory droplets containing infectious virus between close contacts with unmasked exposure. SARS-CoV-2 is highly contagious and in some cases, individuals may be particularly infectious, leading to “super-spreader” events.
  • The incubation period of COVID-19 is up to 14 days, with symptoms typically beginning 3 to 5 days after exposure.
  • Individuals who are infected with SARS-CoV-2 are most contagious early in their infection. Infectivity is typically the highest within the day of symptom onset and declines over the subsequent 10 days. The duration of viral shedding may be longer for severely ill and immunocompromised individuals.
  • Asymptomatic and presymptomatic individuals can be contagious.
  • Vertical transmission from mother to fetus has been reported but rare.

RISK FACTORS

  • The clinical spectrum of SARS-CoV-2 infections in children can vary from asymptomatic to severe.
  • In general, infection with SARS-CoV-2 is milder in children than adults. Many children can have asymptomatic infections or mild symptoms limited to the upper respiratory tract.
  • Most hospitalized children with COVID-19 will not require any specific therapy beyond supportive measures.
  • The following conditions may be associated with increased risk of severe disease in children:
    • Chronic pulmonary diseases
    • Congenital heart disease
    • Diabetes mellitus
    • Obesity (body mass index [BMI] ≥95th percentile for age/sex)
    • Immunosuppressive conditions
    • Sickle cell disease
    • Neurologic conditions

GENERAL PREVENTION

ALERT

Health care professionals caring for patients with suspected or known case of COVID-19 should wear personal protective equipment (PPE) to reduce the risk of exposure, including gloves, gown, a respirator or medical mask, and eye or face protection. A respirator of N95 level or higher is recommended for aerosol-generating procedures (e.g., bronchoscopy, intubation, extubation).

ALERT

If SARS-CoV-2 infection is known or suspected, the patient should be placed on airborne, droplet, and contact precautions. Well-ventilated single-occupancy room with a closed door and dedicated bathroom are optimal. Airborne isolation rooms are recommended if aerosol-generating procedures are anticipated.

  • COVID-19 vaccination is recommended for ages ≥6 months in accordance with Centers for Disease Control and Prevention (CDC) guidelines.
  • mRNA-based vaccines are highly effective against severe COVID-19 illness and symptomatic COVID-19.
  • Vaccination may reduce duration of viral shedding and transmission to secondary contacts.
  • Wearing face masks or coverings, physical distancing (>6 feet between people), avoiding crowds, isolating when infectious, and practicing good hand hygiene can reduce viral transmission.
  • Epidemiologic data support community masking to reduce the spread of SARS-CoV-2 when COVID-19 rates are high and as recommended by public health.
  • Preexposure prophylaxis with monocloncal antibodies for high-risk patients with tixagevimab-cilgavimab (Evusheld®)
    • Investigational drug that is a long-acting combination monoclonal antibody targeting the spike protein
    • Received emergency use authorization (EUA) from the U.S. Food and Drug Administration (FDA) for preexposure prophylaxis for persons aged ≥12 years (≥40 kg) with moderate/severe immunocompromise not expected to mount an adequate antibody response to COVID-19 vaccination
    • Repeat dosing is recommended every 6 months in patients who need ongoing protection.

PATHOPHYSIOLOGY

  • SARS-CoV-2 is a positive sense, single-stranded enveloped RNA virus made up of four key structure proteins: the spike (S), membrane (M), envelope (E), and nucleocapsid (N).
  • The viral S protein binds to the angiotensin-converting enzyme 2 (ACE2) receptor found in the eyes, respiratory tract, and GI tract, leading to viral entry into host cells.
  • Active replication and release of virus in the epithelium of the respiratory tract leads to nonspecific symptoms such as fevers, headache, myalgias, congestion, and cough.
  • SARS-CoV-2 can cause direct endothelial damage, microvascular dysfunction, and a “leaky state,” promoting inflammation and coagulation.

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