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This article contains information about Novel Coronavirus (COVID-19) – which in March 2020 was declared a pandemic by the WHO. Information and public health advice about the virus (SARS CoV-2) and the illness it causes (COVID-19) is changing rapidly. It is recommended that you seek the advice of your local government health authority for the latest information. 

This article will be updated at the pandemic progresses.

Introduction

Coronaviruses are a family of viruses that cause respiratory infections in humans. Most coronaviruses cause a mild illness – for example – coronaviruses are responsible for about 1/4 of cases of the common cold.

However, some coronaviruses can cause severe respiratory distress, such as pneumonia and ARDS, and can have a significant mortality rate.

Significant outbreaks of deadly coronaviruses include:

  • Middle East Respiratory Syndrome (MERS-CoV) – which caused various outbreaks in the 2010s. MERS had a mortality rate of about 35%
  • Severe Acute Respiratory Syndrome (SARS-CoV) – which caused an outbreak in China and Hong Kong in 2002-03. SARS had a mortality rate of about 10%
  • Novel coronavirus (SARS-CoV-2) which causes the illness known as COVID-19

Novel Coronavirus (COVID-19)

  • The virus itself its official called SARS CoV-2
  • The respiratory illness it causes is known as COVID-19
  • The term COVD-19 is often used interchangeably for both purposes

Novel coronavirus was first identified in the city of Wuhan in Hubei, China, around the end of 2019. It is belief to have originated in the live animal market in Wuhan – probably in bats (not as first suggested the pangolin).

By January 2020 it was confirmed to be spreading from person to person.

In March 2020 it was declared a pandemic by the WHO.

There is currently no vaccine available for the virus.

Stringent hygiene such as regular hand washing and avoiding touching your face can reduce the risk of infection. Public health measures to limit person to person contact may help to reduce the rate of spread amongst the population.

The virus seems to disproportionally affect older patients and those with pre-existing health conditions. There are very few cases identified in children.

The current outbreak is expected to last at least several months.

Presentation

  • Can be very variable
  • An unknown proportion (up to 40% of cases) are asymptomatic
  • The illness peaks between days 9-13
  • Most patients who become sick enough to require hospital admission have presented by day 5
  • Typical presentations involve flu-like symptoms such as:
    • Fever – 88%
    • Cough – 67%
    • Fatigue – 38%
    • Shortness of breath – 18%
    • Muscle aches – 15%
    • Headache – 14%
    • Sore throat – 14%
    • Coryza – 5%
    • Nausea / vomiting – 5%
    • Diarrhoea – 4%

Symptom severity

  • 80% of cases are mild and can be treated at home
  • 20% of cases require hospital admission – typically for treatment of shortness of breath secondary to pneumonia or ARDS
  • 5% of cases require ICU admission – typically for ARDS, respiratory failure, sepsis and multi-organ failure
  • The median time from onset to ICU admission is 10 days
  • Average time from symptom onset to death is 2-8 weeks

Infectivity

The Ro number refers to on average how many people and affected person will infect. 

  • A disease with an Ro on <1 will typically slowly decline in number of cases, and eventually disappear
  • A disease with an Ro number of >1 can propagate widely throughout a population
  • The Ro of coronavirus is estimated to be 1.5 – 3.4
    • Ro of influenza is about 1.3

For a really interesting interactive simulation on infectivity, and how it can be altered using social isolation methods, try this simulation from The Washington Post.

Incubation

  • The average incubation period is 5 days
  • The  typical range is between 2-14 days
    • There is a single confirmed case after 27 days incubation
  • It is believed that the virus can be shed during the asymptomatic incubation period, or in individuals who are completely asymptomatic

Transmission

  • Transmission occurs from person to person by droplet transmission, mucous membranes, faecal-oral route and via fomites (contaminated inanimate objects – such as door handles and other surfaces)
  • The virus can survive for at least 48 hours on surfaces

Diagnosis

Consider COVID-19 in any patient with:

  • Cough, OR
  • Fever

AND

  • Overseas travel to a high risk area within 14 days on onset of symptoms, OR
  • Contact with a confirmed case of COVID-19

Contact is defined as:

  • Living in the same household as a person with confirmed infection
  • Direct contact with someone who has a confirmed infection, or their bodily fluids
  • Face-to-face contact with a person with a confirmed infection for any length of time
  • Being within 2 metres of a person with a confirmed infection for more than 15 minutes

If the above conditions are met, then consider nasopharyngeal PCR swab:

  • Nasophayrngeal swab for coronavirus PCR testing
    • Highly sensitive and specific
    • Typically takes 48-72 hours for a result
    • Latest advise is to take x2 samples with a single swab – nasopharyngeal (via nose) and throat
  • CT chest
    • Bilateral ground glass infiltrates
    • Not specific, but can be considered diagnostic in the context of clinical symptoms consistent with coronavirus

Healthcare workers: recommendations may be different for healthcare workers. In Australia it is recommended all healthcare workers with fever and respiratory symptoms are screened, even if they don’t meet the contact requirements. 

Management

No specific treatment is available. Care is supportive – mainly in the form of assisted oxygenation and ventilation in those with severe disease.

  • Corticosteroids should be avoided

Mild infection

Mild cases can be managed safely at home. Advise should be similar to that of other common upper respiratory tract infections, such as:

  • Simple analgesia – e.g. paracetamol 1g QID
  • Oral fluids – titrate to urine output – aim for straw coloured urine, passing urine at least x3 per day
  • Safety-net instructions – such as – advise to seek medical review if increasing shortness of breath, light-headed or dizzy (pre-syncope), or syncopal symptoms, or generally unwell

Self isolation is an important public health measure for anybody with confirmed or suspected COVID-19. 

  • Self isolation should last until symptoms have resolved, OR
  • Should last for 14 days in asymptomatic individuals advised to self isolate (see prevention below)
  • Self-isolation should involve:
    • Staying at home, or your hotel or place of residence
      • Going outside to private gardens is OK
    • NOT allowing visitors
    • DO NOT visit public places, including schools, work, childcare, university, other public gatherings
    • DO NOT use public transport
    • Ask friends or relatives who are not in isolation to fetch food and any other items you many need. Online shopping may also be an option
    • Infected patient should wear a face mask in any communal areas of the home to reduce the risk of droplet transmission
      • Wearing a mask for non-infected patients is unlikely to reduce their risk of catching the infection
    • Other people in the house:
      • Will also be required to self-isolate if they have been in close contact with a confirmed infection (see close contact rules, above)
    • Coping with self isolation
      • Keep a regular routine – e.g. eating regular meals
      • Work from home if possible
      • Take regular exercise
      • Arrange activities for children – and try to keep up with any school-work via email or other electronic means
  • Cleaning around the house to minimise transmission – regular household detergent is suitable. Advise patients to regular wash any surfaces that are frequently touched in the home, such as:
    • Door handles
    • Light switches
    • Kitchen and bathroom areas

Indicators of mild infection include:

  • No shortness of breath
    • O2 sats >92% on room air
    • Speaking in full sentences
    • Respiratory rate not raised
    • No signs of increased work of breathing
  • Not hypotensive
    • No symptoms of pre-syncope or syncope, or signs of postural hypotension
  • Normal heart rate – not tachycardic (HR <100)

Severe infection

  • About 20% of cases are expected to require hospital admission
  • The mainstay of treatment is supportive respiratory care – such as:
    • Oxygen to maintain O2 sats >= 93%
    • Intubation and ventilation in the most severe cases
    • Other organ support in multi-organ failure
  • The role of antiviral medication is as yet unclear
  • Typical time from onset of illness to development of ARDS is 8-9 days
  • 10% of patients develop secondary infections

Prevention

Basic hygiene measures may help to reduce the spread of the virus:

Coronavirus COVID-19 - measures to reduce the spread of the virus

Coronavirus COVID-19 – measures to reduce the spread of the virus

Governments around the world, as of 15th March 2020, are being to enact restrictions on the movement and meeting of people and crowds. The aim of this is to slow the spread of the disease.

Minimising social contact is the main way to slow down the spread of the virus.

COVID-19 - slowing the spread to relieve pressure on health services

COVID-19 – slowing the spread to relieve pressure on health services

In addition to population measures to prevent spread, certain populations (such as those recently returning from high risk areas) are being advised to self-isolate, regardless of whether or not they have symptoms.

Prognosis

  • 80% of patients have mild symptoms – similar to a common cold or the flu
  • 20% of patients require hospital admission
  • 5% require ICU admission
  • Novel coronavirus has about a 2% mortality
    • This is not evenly distributed, and disproportionally affects older and co-morbid populations
    • The exact mortality rate cannot be accurately calculated until after the outbreak is over – through retrospective testing of the population for coronavirus antibodies to calculate the true incidence of the disease

Mortality by age

Age
Mortality rate
80+15%
70-798%
60-693.6%
50-591.3%
40-490.4%
30-390.2%
20-290.2%
10-190.2%
0-9No known fatalities
Coronavirus COVID-19 mortality rate by age

Coronavirus COVID-19 mortality rate by age

Mortality by pre-existing condition

Pre-existing condition
Mortality rate
Cardiovascular disease10%
Diabetes7%
Chronic Respiratory disease6%
Hypertension6%
Cancer6%
None0.9%
Coronavirus COIVD-19 mortality rate by comorbidity

Coronavirus COVID-19 mortality rate by comorbidity

Public health implications

  • Peak incidence in any given country or region is expected to occur about 2 months after the first cases
  • 20-80% of the population is likely to be infected
  • Duration of the pandemic is likely to be 6-12 months
    • After this, the future of the virus is uncertain. It may become endemic – circulating amongst the population indefinitely.
    • This could be either as a seasonal illness and rapidly mutating illness – like influenza – or as a non-seasonal disease – like chicken-pox
  • A vaccine is under development but will probably not be available until mid 2021
  • Previous infection is likely to provide immunity for at least several years
  • The aim of public health measures is to slow the rate of spread
    • It is believed it is no longer possible to contain the virus
    • By slowing the spread of the virus, the peak of cases can be widened, reducing the peak load on health services
    • There are concerns that in a brief and large outbreak, there will not be sufficient hospital and ICU beds to treat all those that will require hospital admission
    • This has been succinctly described by Tim Stellar on twitter:

      Graph of the spread of novel coronavirus

      Graph of the spread of novel coronavirus

References