SARS is a highly infectious respiratory viral disease, which presents much like flu (fever, sore throat, dry cough, headache, chills, stiff muscles). Quarantining of patients is the only option, however there have been no reported cases of SARS since 2004.…
Novel coronavirus (COVID-19)
What is a coronavirus and COVID-19?
Coronaviruses are type of virus. They are many kinds and can make humans and animals sick. Some coronaviruses can cause illness similar to the common cold and others can cause more serious diseases, including Severe Acute Respiratory Syndrome (SARS) and Middle East respiratory syndrome (MERS).
A new strain of the coronavirus identified in Wuhan City in China in December 2019 was named SARS-CoV-2  . This novel (new) coronavirus has caused a global infectious disease pandemic (COVID-19) for more than two years.
Similar to other viruses, the Novel coronavirus change over time. Some changes (mutations), especially the variants of interest (VOIs) and variants of concern (VOCs) affect the virus's properties such as speed of spread, severity of illness, performance of vaccines, therapeutic drugs, diagnostic tools, public health and social strategies. Currently the circulating variants of concern are Delta and Omicron  .
At time of writing this topic, the COVID-19 pandemic has caused 477 million cases around the world, 87% of them recovered, and more than 6 million deaths  . Some recover but go on to develop chronic symptoms. This is known as "long covid".
The novel coronavirus is the cause of COVID-19. This virus is most likely to spread from person-to-person through:
- direct close contact with a person while they are infectious. This may include a period of 14 days or more before symptoms begin, or
- close contact with a person with a confirmed infection who coughs or sneezes, or
- touching objects or surfaces (such as door handles or tables) contaminated from a cough or sneeze from a person with a confirmed infection, and then touching your mouth or face.
The coronavirus is spread through droplets and virus particles released into the air when an infected person breathes, talks, laughs, sings, coughs or sneezes. Tiny infectious particles can linger in the air and accumulate in indoor places, especially where many people are gathered and there is poor ventilation. Symptoms show up in people within 2 to 14 days of exposure (incubation period). Mostly within 5-7days. A person infected with the coronavirus is contagious to others for up to two days before symptoms appear, and they remain contagious to others for 10 to 20 days  . Mostly 7-10 days.
About 3-17% of COVID-19 patients develop a complication known as Acute Respiratory Distress Syndrome (ARDS)  . The patients with severe symptoms need to be admitted in hospital or require a ventilator.
Some people who are infected may not get sick at all, some others will get mild symptoms from which they will recover easily and quickly, but a small proportion of people may become very ill, very quickly. The people at most risk of serious illness are  [ 7] :
- older age (70 years and over),
- lung problem including asthma, COPD, cystic fibrosis, pulmonary fibrosis, pulmonary hypertension, pulmonary embolism,
- smoking and vaping,
- heart problem, including cardiomyopathy, congenital heart disease, heart failure, coronary artery disease,
- brain and nervous system diseases,
- diabetes and overweight/obesity,
- compromised immune system
- cancer and certain blood disorders
- chronic kidney or liver disease
- mental health conditions
Signs and symptoms
Most people with COVID-19 have mild or moderate symptoms, but some can become severely ill. Older people and patients with underlying medical conditions are more likely get severely ill from COVID-19.
- fever or chills,
- fatigue or tiredness,
- loss of taste or smell,
- congestion or runny nose,
- sore throat
The less common symptoms include:
- muscle aches,
- diarrhea, nausea or vomiting
- rash on skin, or discolouration of fingers or toes
- red or irritated eyes
The serious symptoms include:
- short of breath,
- loss of speech or mobility, or confusion,
- chest pain.
Methods for diagnosis
Clinical suspicion: the possibility of COVID-19 should be considered in anyone with new onset fever and/or respiratory. As the virus is prevalent worldwide, doctors have a low threshold for suspicion of COVID-19, especially for who have high risk of infection.
Testing: all symptomatic patients with suspected infection should do testing. Testing certain asymptomatic persons might be also necessary for infection control purposes. Other testings might also apply such as for patients admitted to hospital, prior to surgical procedures or some immunosuppressive treatment.
The rapid antigen test (RAT) is a quick screening and an alternative method and can be managed by individuals, at home or at point of care, for the purpose of detecting more infections as quickly as possible. RAT positive needs to be reported, and the person should follow self-isolation regulation for minimum 7 days  .
The diagnostic test of confirming the COVID-19 is a laboratory test, called nucleic acid amplification testing (NAAT). It is commonly done with a reverse-transcription polymerase chain reaction (RT-PCR) assay, to detect SARS-CoV-2 RNA from the upper respiratory tract, so people also simply call it 'PCR test'  .
While COVID-19 is of concern, it is important to remember that most people displaying symptoms such as fever, cough, sore throat or tiredness are likely suffering with a common cold or other respiratory illness--not COVID-19.
Methods of management
Management strategies might be different across jurisdictions. From a public health perspective COVID-19, management will be considered at public level and individual level. The management is also varied depend on degree of severity, individual and herd immunity level, availability of resources.
At an individual level, if you think you may have contracted coronavirus or been in close contact with a confirmed case of coronavirus, do a RAT at home. If it is positive, you have to stay at home and do not attend public places, including work, school, childcare or university. You must phone your health provider (such as your GP) for further instructions as soon as possible. You must notify the Department of Health if the RAT is positive and stay isolated for at least 7 days or until the RAT is negative. If you have symptoms with a negative RAT and have been in contact with a positive case you should arrange to have a PCR. Remember the RAT is only 90% reliable.
If you develop symptoms, you should wear a mask and phone your healthcare provider to get advice and directions on where to go for urgent assessment or should be admitted in hospital. You must remain isolated either in your home or a healthcare setting until public health authorities inform you it is safe for you to return to your usual activities.
Do not allow visitors into the home. Where possible, get others such as friends or family who are not required to be isolated to get food or other necessities for you. If you must leave the home, such as to seek medical care, wear a mask if you have one.
It is also worthwhile to remember to continue maintaining your health during the pandemic, including chronic disease management (if applicable) and mental health.
Methods of treatment
There is no specific treatment for coronaviruses.
For patients with mild symptoms treat COVID-19 in a similar way to treating a seasonal flu: rest at home, take paracetamol or ibuprofen to relieve pain and fever, stay hydrated, and take cough medicine if needed. You should monitor your symptoms  and seek help if concerned.
For patients with severe symptoms, contact your doctor. You may need to be treated in hospital particularly if your oxygen levels are low and you are short of breath. In these circumstances an ambulance should be called. Most of the symptoms generally can be treated with supportive medical care.
The Therapeutic Goods Administration (TGA) has provisionally approved certain medicines for the treatment of COVID-19 in Australia. The medicines include Sotrovimab (Xevudty) and Remdesivir (Veklury)  . New antiviral agents, in tablet form, have been provisionally approved by the TGA for use in General Practice as well as in hospital. The treatment must be used within the first 5 days on onset of the illness in those over 18 who have mild to moderate symptoms, do not require oxygen but are at risk for progression to more severe disease. These drugs include molnupirvir and nirmatrelvir in combination with ritonavir  .
Antibiotics, ivermectin and hydroxychloroquine are not effective against viruses that causes COVID-19.
Some people experience ongoing symptoms after recovering from acute phase of COVID-19. It is called chronic COVID or long COVID. Half of hospitalised COVID patients (severe cases) developed complications. These symptoms might last weeks to months. The most frequently observed issues were renal, complex respiratory and systemic complications  . The most common symptoms are fatigue, shortness of breath, change sense of smell and/or taste, chest pain, lack of sleep, headache, etc.
Medical research is being conducted around the world on the short- and long-term health effects of COVID-19. It is currently uncertain how long these symptoms may persist  .
Patient with mild to moderate COVID-19 recover with general treatment. It is estimated that 81% of patients experience mild symptoms, 14% have a severe disease requiring hospitalisation, and 5% of patients become 'critical'  .
The mortality of COVID-19 appears lower than SARS and MERS. Mortality may be changing as the pandemic progresses. The risk factors for death include severe ARDS (need ventilation) , comorbidities (such as obesity, COPD, hypertension diabetes, kidney disease, renal replacement therapy, cancer), markers of inflammation and coagulation, etc. 
COVID-19 vaccination is one of the effective and safe ways to prevent COVID-19, especially to reduce severity of the disease, hospitalisation and death. So, get vaccinated. Because the Delta and Omicron variants became dominant virus and are more contagious ,they are likely to escape vaccine's protection, we need very high rates (over 90%, and triple doses) of everyone vaccinated including younger children  .
Vaccination itself is not enough to tame the Delta and Omicron variants  . All 'classic' methods are also important and effective preventive strategies, even we have high rate of vaccination, these personal preventive strategies including
- wearing mask, social/physical distancing, hand hygiene, avoid crowds, and stay away from others if you feel sick,
- wash your hands frequently with soap and water, before preparing food, before and after eating, and after going to the toilet, or using sanitizer when you cannot access water and soap,
- cover your cough and sneeze, dispose of tissues, and use alcohol-based hand sanitiser,
- if unwell, avoid contact with others (touching, kissing, hugging, and other intimate contact).
- Centers for Disease Control and Prevention. Frequently Asked Questions. 2021 [cited 2021 23 Nov ]; Available from: link here
- World Health Organization. Tracking SARS-CoV-2 variants. 2022 [cited 2022 24 March]; Available from: link here
- Coronavirus Resource Centre of Johns Hopkins University and Medicine. COVID-19 Dashboard by the Center for Systems Science and Engineering at Johns Hopkinds Univeristy 2022 [cited 2022 24 March ]; Available from: link here
- Medicine, J.H. Coronavirus (COVID-19) information and updates. 2022 [cited 2022 20 arch 2022]; Available from: link here
- Yale School of Medicine. Challenge 5: how does COVID-19 afect the respiratory system? 2022 [cited 2022 23 March ]; Available from: link here
- Australian Government Department of Health. People at higher risk of coronavirus (COVID-19). 2021 [cited 2021 Nov 23]; Available from: link here
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FAQ Frequently asked questions
What is coronavirus disease (COVID-19)?
COVID-19 is an infectious disease that has caused a global pandemic for more than two years. The disease is transmitted from person-to-person.
What are signs and symptoms of the COVID-19?
Most people with COVID-19 have mild or moderate symptoms, such as fever or chills, cough, tiredness, loss of taste or smell, congestion or runny nose, sore throat. People might also have uncommon signs such as headache, muscle pain, diarrhea, …
What caused COVID-19?
The novel coronavirus is the cause of COVID-19. It was identified in Wuhan City in China in December 2019. The novel coronavirus changes over time (mutations. Currently the circulating variants of concern are Delta and Omicron.
How to get COVID-19?
People might be infected through direct close contact with a person while they are infectious. The infected person might or might not have symptoms. The coronavirus is spread through droplets and virus particles released into the air when an infected person breathes, …
How is the COVID-19 diagnosed?
The diagnostic test of confirming the COVID-19 is a laboratory test, called nucleic acid amplification testing, NAAT), people also simply call it ‘PCR test’. The rapid antigen test (RAT) is a quick screening and an alternative method and can be managed by …
How is the COVID-19 treated?
There is no specific treatment for coronaviruses. For patients with mild symptoms treat COVID-19 in a similar way to treating a seasonal flu. Patients with severe symptoms may need to be treated in hospital or require a ventilator. New antiviral agents have …
How long does the COVID-19 infection last?
Symptoms show up in people within 2 to 14 days of exposure (incubation period). Mostly within 5-7days. A person infected with the coronavirus is contagious to others for up to two days before symptoms appear, and they remain contagious to others …
How to prevent the COVID-19?
It includes public and individual strategies. Vaccination is one of the effective and safe ways to prevent COVID-19, especially to reduce severity of the disease, hospitalisation and death. So, get vaccinated. All ‘classic’ methods (wearing masks, social …
How is the COVID-19 spread?
The coronavirus is spread through droplets and virus particles released into the air when an infected person breathes, talks, laughs, sings, coughs or sneezes. Tiny infectious particles can linger in the air and accumulate in indoor places, especially where many …