This transmission electron microscope image shows SARS-CoV-2 isolated from a patient in the U.S. Virus particles are shown emerging from the surface of cells cultured in the lab. The spikes on the outer edge of the virus particles give coronaviruses their name, crown-like. Image captured and colourised at NIAID's Rocky Mountain Laboratories (RML) in Hamilton, Montana.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the recently emerged human coronavirus (COVID-19) pandemic. SARS-CoV-2 is an RNA virus which belongs to the coronavirus family (Coronaviridae), genus Betacoronavirus. Coronaviruses are named for the crown-like spikes on their surface which resemble the corona of the sun and contain an RNA genome which is protected by an outer envelope with protruding proteins. SARS-CoV-2 is the seventh coronavirus to emerge and cause respiratory disease in humans.

  • COVID-19 is a notifiable disease and should be reported.
    Please visit the World Health Organization (WHO) website for advice on symptoms and how to prevent its spread. 

Associated diseases:

SARS-CoV-2 causes COVID-19, a disease that can vary enormously in severity and in the symptoms displayed. Huge global research efforts are underway to understand more about the virus and how it infects humans. There is currently no treatment or vaccine available and therefore biosecurity measures are essential to prevent the spread of the virus.

Symptoms typically occur five to six days after infection, but can take up to 14 days. Most people that become infected will develop mild to moderate illness and recover without hospitalisation. The elderly and those with underlying health conditions are at greater risk from developing serious symptoms. WHO defines the symptoms as below.

Most common symptoms:

  • fever
  • dry cough
  • tiredness

Less common symptoms:

  • loss of taste or smell
  • aches and pains
  • sore throat
  • diarrhoea
  • conjunctivitis
  • headache
  • a rash on skin, or discolouration of fingers or toes

Serious symptoms:

  • difficulty breathing or shortness of breath
  • chest pain or pressure
  • loss of speech or movement

For advice on what you should do if you have any of these symptoms, please visit the NHS website (for those in the UK) or consult your local health care provider in your country.

Disease transmission:

COVID-19 can be spread from human-to-human via small droplets that are expelled when an infected individual coughs, sneezes or speaks. People can become infected if they inhale these droplets or transfer them to their face after touching a contaminated surface.

It is accepted that bats are the most likely original host of SARS-CoV-2 as there are viruses in horseshoe bats with comparable genomes that have been identified since the severe acute respiratory syndrome (SARS) outbreak in 2003. It is expected that there will have been an intermediate host, although which species is currently unknown. Other animals such as cats, dogs and mink have also been found to test positive for SARS-CoV-2, but there is no current evidence that these animals are able to spread the disease to humans. Research is ongoing in this area.

Disease prevalence:

COVID-19 was first reported in Wuhan, China, in December 2019. Since then, the disease has spread to over 200 countries and territories, resulting in over 33 million confirmed cases and over one million deaths. Unprecedented control measures have been taken to prevent the spread of COVID-19, with many countries resorting to lockdowns to reduce case numbers but which have also prevented many from working. This has caused worldwide economic disruption. The pandemic is still ongoing - for up to date information on the spread of COVID-19, visit the WHO website.

Impact for Society – what are we doing?

The Pirbright Institute has a history of working with livestock coronaviruses, primarily focused on studying how coronaviruses replicate and interact with their host cell and developing effective vaccines for infectious bronchitis virus (IBV), a poultry disease that has a huge financial impact on the UK poultry industry.

Our scientists are now applying their expertise to help with the COVID-19 research effort. In collaboration with the University of Oxford, Pirbright has successfully shown that two doses of the ChAdOx1 nCoV-19 (AZD1222) vaccine produce a greater antibody response than a single dose in pigs. Pirbright is using the same pig model to establish the immune response generated by Imperial College London’s RNA vaccine, as well as establishing the dosage size that may be needed in order to protect humans. Using the pig model will help to inform the development of vaccines that are both effective and safe for humans.

Other Pirbright COVID-19 research projects have explored the mechanisms SARS-CoV-2 uses to enters cells, which have recently demonstrated that SARS-CoV-2 has the potential to infect multiple mammalian species. Work generating reagents and tests to explore diagnostic options for SARS-CoV-2 is also ongoing.

Pirbright is assisting the UK Government during the pandemic by supplying 13 of its high-throughput testing instruments to the UK’s National Coronavirus Testing Centre in Milton Keynes. Over 60 of Pirbright’s diagnostic staff and scientists have also volunteered to join the testing effort at seven Public Health England testing sites across the country and at Pirbright’s local NHS hospital to increase the UK’s diagnostic capacity.

Pirbright’s research into IBV and other coronaviruses such as porcine deltacoronavirus will continue to further expand our knowledge of how this family of viruses infect hosts and replicate within cells. Building upon this coronavirus expertise, Pirbright scientists will investigate how SARS-CoV-2 replicates and incorporate this into comparisons between other coronaviruses, which could provide vital insights for vaccine and antiviral development. Testing potential antivirals will also form an important part of Pirbright’s SARS-CoV-2 research programme.

Research papers

Conceicao C, Thakur N, Human S, Kelly J T, Logan L, Bialy D, Bhat S, Stevenson-Leggett P, Zagrajek A K, Hollinghurst P, Varga M, Tsirigoti C, Hammond J A, Maier H J, Bickerton E, Shelton H, Dietrich I, Graham S C, Bailey D (2020)

bioRxiv , 156471
Graham S P, McLean R K, Spencer A J, Belij-Rammerstorfer S, Wright D, Ulaszewska M, Edwards J C, Hayes J W P, Martini V, Thakur N, Conceicao C, Dietrich I, Shelton H, Waters R, Ludi A, Wilsden G, Browning C, Bialy D, Bhat S, Stevenson-Leggett P, Hollinghurst P, Gilbride C, Pulido D, Moffat K, Sharpe H, Allen E, Mioulet V, Chiu C, Newman J, Asfor A S, Burman A, Crossley S, Huo J, Owens R J, Carroll M, Hammond J A, Tchilian E, Bailey D, Charleston B, Gilbert S C, Tuthill T J, Lambe T (2020)

npj Vaccines 5 (1) , 69
Petrovan V, Vrajmasu V, Bucur A C, Soare D S, Radu E, Dimon P, Zaulet M (2020)

Diagnostics 10 (7) , 472
Snijder E J, Limpens R, de Wilde A H, de Jong A W M, Zevenhoven-Dobbe J C, Maier H J, Faas F, Koster A J, Bárcena M (2020)

PLoS Biology 18 (6) , e3000715
van Doremalen N, Haddock E, Feldmann F, Meade-White K, Bushmaker T, Fischer R J, Okumura A, Hanley P W, Saturday G, Edwards N J, Clark M H A, Lambe T, Gilbert S C, Munster V J (2020)

Science Advances 6 (24) , eaba8399

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