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Other human coronaviruses

  • Virus
  • Enveloped
  • ContactGown and gloves; dedicated equipment. For C. difficile, soap-and-water hand washing.
  • AirborneN95 respirator and a negative-pressure room.
  • Exam priority: medium

Seven coronaviruses infect people. Four cause common colds; SARS-CoV-1 and MERS-CoV, both from animals, cause severe pneumonia and hospital outbreaks.

Updated

Also called: HCoV-229E, HCoV-NL63, HCoV-OC43, HCoV-HKU1, SARS-CoV-1, MERS-CoV

Quick facts

Type
Virus · Respiratory RNA viruses
Gram / shape
Spherical with club-shaped spikes
Spread
Seasonal HCoVs · SARS-CoV-1 · MERS-CoV
Causes
Common cold · Croup in young children

At a glance

Shape
Spherical with club-shaped spikes that look like a crown
Genome
Single-stranded, positive-sense RNA (about 30 kb, the largest RNA virus genomes)
Envelope
Enveloped
Family
Coronaviridae: alphacoronaviruses (229E, NL63) and betacoronaviruses (OC43, HKU1, SARS-CoV-1, MERS-CoV, SARS-CoV-2)
Size
About 80 to 160 nm

Morphology

  • Spike (S) protein binds the receptor: ACE2 for SARS-CoV-1 and NL63, DPP4 for MERS-CoV, aminopeptidase N for 229E
  • OC43 and HKU1 also carry a haemagglutinin-esterase
  • Helical nucleocapsid inside the envelope

Transmission

  • Seasonal HCoVs: respiratory droplets, close contact and contaminated hands; winter peaks in temperate countries
  • SARS-CoV-1 (2002 to 2004): bats as the source, masked palm civets in markets as the intermediate host, then person to person
  • MERS-CoV: dromedary camels (contact, raw milk, urine, undercooked meat); limited person-to-person spread, mainly in households and hospitals
  • Large hospital clusters followed aerosol-generating procedures and gaps in infection control
  • Precautions: standard for seasonal colds; for suspected MERS or SARS, contact plus airborne precautions with eye protection

Reservoir: Bats (ancestral source of SARS-like and MERS-like viruses); Dromedary camels (MERS-CoV); Humans (seasonal HCoVs)

Isolation precautions

What the care team adds to standard precautions.

Contact
Gown and gloves; dedicated equipment. For C. difficile, soap-and-water hand washing.
Airborne
N95 respirator and a negative-pressure room.

Virulence factors

  • Seasonal HCoVs infect the upper airway epithelium and cause mild disease
  • SARS-CoV-1 and MERS-CoV reach the lower airway and alveoli, causing diffuse alveolar damage and ARDS
  • MERS-CoV also infects kidney cells, and acute kidney injury is common in severe cases
  • Older age, diabetes, chronic heart, lung or kidney disease and immunosuppression raise the risk of death

Diseases it causes

Clinical picture

  • Seasonal HCoV: rhinorrhoea, sore throat, cough, low fever, lasting a few days
  • SARS: high fever and myalgia, a dry cough after 2 to 7 days, then pneumonia in most patients; diarrhoea in some
  • MERS: fever, cough and dyspnoea about 5 days after exposure (range 2 to 14), often pneumonia; about a third of reported cases died

Diagnosis

  • Multiplex respiratory PCR panels detect the four seasonal HCoVs
  • MERS: RT-PCR on lower respiratory samples (sputum, tracheal aspirate) is preferred, in anyone with pneumonia after travel to the Arabian Peninsula or camel contact
  • Chest imaging shows bilateral infiltrates in SARS and MERS pneumonia
  • Serology is used for surveillance and contact studies

Treatment

There is no specific antiviral recommended for seasonal HCoVs, SARS or MERS: care is supportive (oxygen, ventilation, organ support). Antibiotics are only for proven or suspected bacterial co-infection.

Drug class only; doses and regimens are set by the clinician from the current guideline.

Prevention

  • Hand hygiene and respiratory etiquette for seasonal colds
  • Wash hands before and after contact with camels; avoid raw camel milk, urine and undercooked meat
  • Early isolation, PPE and airborne precautions for suspected MERS in health-care settings
  • No vaccine is licensed for MERS, SARS or the seasonal coronaviruses

Test yourself

Think of the answer, then tap the question to see it.

What is the animal reservoir that infects people with MERS-CoV?

Dromedary camels, through direct contact or raw camel products.

Which human coronavirus is classically linked to croup?

HCoV-NL63, an alphacoronavirus.

Which receptor does MERS-CoV use, unlike SARS-CoV-1?

Dipeptidyl peptidase 4 (DPP4); SARS-CoV-1 uses ACE2.

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Connections

← Back to the group: Respiratory RNA viruses

Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: Human Coronavirus Types (CDC, 2024); Middle East respiratory syndrome coronavirus (MERS-CoV) (World Health Organization (WHO), 2025); About Middle East Respiratory Syndrome (MERS) (CDC, 2024); SARS Basics Factsheet (CDC (archived), 2017).

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Representative model, for educational purposes only.