Last reviewed: 17 Apr 2022
Last updated: 30 Nov 2021
30 Nov 2021

Tecovirimat approved in Europe for the treatment of orthopoxvirus disease

The European Medicines Agency has recommended that the antiviral drug tecovirimat be approved for the treatment of smallpox, monkeypox, and cowpox in adults and children with body weight at least 13 kg. It is also indicated to treat complications due to replication of vaccinia virus following smallpox vaccination.

Tecovirimat is a synthetic small antiviral molecule which inhibits orthopoxvirus peripheral membrane protein (VP37) activity. Its effectiveness was predicted from studies that showed improved survival in animals. The most common adverse effects are headache and nausea.

Although naturally occurring smallpox was eradicated in 1980, there have been long standing concerns that the variola virus could be used as a bioweapon. Cases of monkeypox have been reported in various countries over the last few years, with 3 cases reported in the UK this year.

Tecovirimat is approved in the US for the treatment of smallpox.

See Management: approach

See Management: treatment algorithm

Original source of update



History and exam

Key diagnostic factors

  • presence of risk factors
  • fever
  • vesicular rash
  • oropharynx and tongue enanthem
  • lymphadenopathy

Other diagnostic factors

  • headache
  • backache
  • pharyngitis
  • vomiting
  • diarrhoea
  • delirium
  • convulsions

Risk factors

  • contact with laboratory (smallpox)
  • bioterrorism (smallpox)
  • close contact with known case (smallpox)
  • contact with monkeypox in animals or humans

Diagnostic investigations

1st investigations to order

  • vesicle specimen PCR
  • FBC
  • urea and electrolytes
  • LFTs
  • venous lactate
  • clotting screen

Treatment algorithm



Tom Blanchard, DTM&H, PhD, FRCP

Consultant in Infectious Diseases

Department of Infectious Diseases and Tropical Medicine

North Manchester General Hospital




TB is the principal investigator on an MRC/Wellcome/Newton Fund grant to make a Zika vaccine based on recombinant modified vaccinia Ankara.

Peer reviewers

Jimmy Whitworth, MD, FRCP

Professor of International Public Health

London School of Hygiene & Tropical Medicine




JW declares that he has no competing interests.

Ashley Styczynski, MD, MPH

Epidemic Intelligence Service Officer

Poxvirus and Rabies Branch

Centers for Disease Control and Prevention




AS declares that she has no competing interests.

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