Coronavirus

2019-nCoV is causing the epidemic in China. It is “zoonotic”, being transmissible from animals to humans, in this case from bats. It is classified as a betacoronavirus, the same group that caused the SARS (severe acute respiratory syndrome) epidemic in 2002-2003 from civets to bats in Southern China and MERS (Middle East respiratory syndrome) in 2012-2015 from bats to camels in Saudi Arabia and the Arabian Peninsula. (PMID 32031583)

2019-nCoV has the potential to become pandemic; the would-be first pandemic of the 21st century. There were three influenza pandemics in the 20th century – 1918 (Spanish in origin), 1957 (Asian) and 1968 (Hong Kong). (16494710)

2019-nCoV is NOT an influenza virus.

The virus spreads rapidly through direct contact with infected individuals and their respiratory secretions, by indirect contact via fomites such as keyboards, doorknobs, toys, lift buttons, any hard surface, and by inhalation of virus particles.

A single sneeze can give rise to 40,000 virus containing droplets which travel up to 2 meters before falling to a surface, or evaporating to “droplet nuclei” which persist as a solid aerosol (in air) for up to 30 hours. The aerosol viral particles when inhaled into the lungs are 20 times more infectious than droplet inoculation from the eyes or the nose. Schools are particular “hot spots”.  (32024882)

There is “limited evidence” that “non-pharmaceutical interventions” (NPIs) are effective, such as hand hygiene and wearing of surgical paper masks, but influenza viruses do persist on human hands and on contaminated surfaces for a short time (3 to 12 hours). Although the coronavirus is not influenza, common sense dictates that frequent hand washing (soap and water or alcohol hand rub) could be helpful and that paper surgical masks could contain droplet infection FROM an infected person.

So called “respiratory etiquette” such as coughing/sneezing into a crooked elbow is not useful, but paper tissues are effective in capturing droplets, as long as the tissue is safely disposed of as soon as possible – if not earlier, i.e. down the nearest lavatory.

Other infections are controlled partly by surface cleaning but apparently not in the case of coronaviruses. (32027586)

Travel related NPIs, such as total border closures, travel restrictions and entry screening have limited effect due to the lack of herd (population) immunity throughout the world and consequent high susceptibility, and are patently impractical and disruptive. It is computed that such interventions could delay international spread by 2 to 19 weeks and importation of first cases by 1 to 8 weeks. (32027587).

There is no vaccine. One in development is estimated to take a further 12 months to become available.

The incubation period for 2019-nCoV is 14 days; much longer than the 2 days for influenza, enabling a carrier to infect many more people.

The symptoms of 2019-nCoV infection are fever above 38°C (100°F), cough and shortness of breath. 5% of cases have a sore throat and/or a nasal discharge. 1-2% have diarrhoea and/or nausea and vomiting. The WHO have classified 14% of the first 20,000 cases in China as “severe”. (February 2020).

The diagnosis of 2019-nCoV is through a well-established, high throughput immunoassay technique developed following the SARS epidemic of 2003. This quick test predicted the next zoonotic CoV, the MERS-CoV of 2012, and is of vital importance in the control of the present epidemic. (24841273)

Severe cases tend to occur in the elderly (older than 65) and those compromised by chronic illnesses such as diabetes, renal and cardiac disorders, and chest diseases.

The severity of a case is otherwise dictated by the size of the viral inoculum inhaled. Medical staff are therefore highly vulnerable.

The death rate from influenza is 0.05%. The death rate of the current coronavirus infection is 2%, but this figure could be skewed by the late diagnosis of “severe cases”.

The treatment of 2019-nCoV is largely symptomatic. Pneumonia is a common complication treatable with antibiotics.

A promising new antiviral, remdesivir, is in development, and the Chinese Government are about to test this in a randomised controlled trial (RCT).

Recent drug-repurposing studies have highlighted a number of potentially effective medications already in common use. These are surprisingly diverse and have proved to be cheap and safe, and effective for their recommended purposes. Probably the most significant is chloroquine, the well-known antimalarial, which has been shown in the laboratory (in vitro) to prevent the betacoronaviruses penetrating human cells. This is joined by chlorpromazine, an antipsychotic; loperamide (Imodium), the anti-diarrhoreal, and lopinavir, an antiretroviral effective in the treatment of HIV, all of which have been successfully tested against SARS-CoV and MERS-CoV of the same family as 2019-nCoV.

TAKEAWAY MESSAGES

• The new Chinese coronavirus (2019-nCoV) epidemic could turn into a world-wide pandemic. It is a serious disease and we have no immunity.
• School children and young adults will spread the virus quickly.
• Avoid contact with obviously infected individuals.
• Wash your hands frequently and try not to rub your eyes. Paper masks do not work.
• Use paper tissues but dispose of them quickly and safely.
• Remember that the incubation period for 2019-nCoV is 14 days.
• Symptoms of 2019-nCoV are high temperature, cough and shortness of breath.
• Occasional symptoms could be sore throat, nasal discharge, diarrhoea, and nausea and vomiting.
• Report any such symptoms to your doctor especially if you have any pre-existing problems such as heart, lung, kidney disorders, or diabetes.
• Diagnosis is quick and easy from a blood test.
• If you have the disease, isolate yourself responsibly. Do not go into work or travel unless necessary.
• There is no vaccine yet, but one is being developed.
• There is no specific treatment yet, but there is one promising antiviral being trialled.
• There are safe existing medications which could work well.