COVID-19 or the coronavirus disease is a highly infectious disease caused by the SARS-CoV-2 virus (severe acute respiratory syndrome coronavirus 2).
It became a pandemic after the first case was observed in December 2019 at Wuhan in China. Since then, millions of people across the world have lost their lives after getting infected by the virus.
COVID-19 causes respiratory illness like a flu attack or common cold. But often, it turns fatal as it starts attacking other organs of the body.
Most people will go through an infection with mild symptoms, but people with certain medical conditions may experience severe illness. People with the following conditions are at a higher risk of developing severe illness due to COVID-19:
- Cardiac disease
- Diabetes
- Cancer
- Lung and kidney disorders
- Persons with organ transplants and a compromised immune system
Symptoms
The incubation period, i.e. the time from exposure to virus till the appearance of the first symptoms, ranges from a couple of days to a couple of weeks. Some of the common symptoms observed so far are:
- Fever, cough, and fatigue
- Body aches
- Loss of taste or smell or both
- Nasal congestion
- Nausea and diarrhoea
A few symptoms that are less common are:
- Sore throat and headaches
- Rashes on the skin
- Red eyes with irritation
Apart from these, there are some warning signs which may require immediate medical care:
- Difficulty breathing and chest pain
- Confusion, difficulty in waking up or staying awake
- Change in colour of skin, lips, or nail beds
- Loss of speech or mobility
Causes
COVID-19 results from an infection with SARS-CoV-2, a novel virus belonging to the coronavirus family. It has proved to be highly contagious and has resulted in severe infections, especially among the elderly and patients with co-morbidities (pre-existing chronic illnesses).
Since its discovery, the RNA (genetic material) of the SARS-CoV-2 virus has undergone many mutations, including the alpha, beta, delta and omicron variants.
Mode of spread
The main mode of transmission of SARS-CoV-2 is through direct or close contact with an infected person. There are, however, other known ways in which one can contract the virus. These are:
- Through inhalation of expelled droplets from an infected person when they speak, cough or sneeze. The droplets can remain airborne for a considerable time and can infect persons even when the carrier has left.
- The virus can also be transmitted by rubbing the eyes, nose or touching the mouth after touching contaminated surfaces or items (fomite transmission).
- The virus can get transmitted from an infected person who shows no symptoms, and also from an infected person who has not yet developed symptoms.
Diagnosis
Along with social distancing, masking, and vaccination, testing for COVID-19 is very important to prevent the spread of infection.
Testing should be performed if:
- an individual shows symptoms of COVID-19
- an individual has been in close contact with a person who has tested positive for COVID-19
- if travelling to school, workplace or a social gathering.
Testing for COVID-19 can be done in two ways:
Viral tests: They can confirm if there is a current infection by using swabs taken from the nose or throat. There are two kinds of viral tests:
- Rapid tests can be done by a healthcare provider or at home by oneself with readily available kits.
- Lab tests such as the RT-PCR (Reverse Transcription-Polymerase Chain Reaction) test are more accurate than rapid tests but require a few hours or days to give results.
Antibody tests: They are also called serology tests and are used to detect antibodies in the blood. Antibodies are proteins developed by the immune system to fight infection and to offer protection against future infection.
These tests do not diagnose current infection, but only offer an indication of recent infection. They are usually done after a complete recovery from COVID-19 infection, to detect whether an individual’s body has developed antibodies.
Antibody tests are useful to select donors whose plasma (the component of blood that contains antibodies) could be given to treat people having serious complications from a COVID-19 infection.
Treatment
Most patients who test positive show mild or no symptoms and will recover with enough care at home. The prescribed care in this situation includes:
- Isolating oneself, preferably in a separate bedroom with a bathroom, till a negative test result is obtained.
- Taking adequate rest along with plenty of fluids.
- Eating paracetamol tablets to bring down fever and mild pain.
- Wearing a mask when others are in the same room.
- Frequent disinfection of surfaces, doorknobs, switches, and utensils.
- If symptoms don’t subside or if they get worse, speak to a doctor and follow the instructions.
If the symptoms require hospital care, among the first signs that will be monitored are:
- Oxygen levels of the blood using a pulse oximeter.
- Lung sounds.
The goal of treatment is to assist the lungs in performing their function, till the infection subsides.
- If needed, extra oxygen may be administered.
- Fluids through an intravenous route are given to prevent dehydration.
- Antiviral medications such as Remdesivir (the only medication universally approved to treat severe cases of COVID-19) may be administered.
- Other mild antiviral medications can be given orally for mild to moderate disease.
- Convalescent plasma which contains antibodies from people who have recovered from COVID-19 can be administered to individuals having severe complications.
- Medications such as corticosteroids and immunosuppressants have been prescribed extensively for hospitalised patients.
Long COVID or post-COVID
Some individuals who contract the COVID-19-causing virus experience unexplained long-term or even recurring symptoms. This condition is seen more frequently among those with severe infections and among the unvaccinated.
Some of these symptoms include:
- Fatigue, fever
- Cough and chest pain
- Rising heart rates
- Dizziness, headache
- Brain fog – difficulty in making decisions
- Diarrhoea
- Rashes on the skin
Prevention
To prevent infection and slow the transmission of COVID-19, the following steps have been found to be useful:
- Getting vaccinated as and when the vaccine or follow-on shots of the vaccine become available to you.
- Maintaining a safe distance of at least 1 metre from other individuals when in public.
- Wearing a well-fitted face mask.
- Washing hands with soap and water, especially after touching items such as doorknobs, switches, bathroom taps, pens, gadgets and so on.
- Using hand sanitisers with over 60 percent alcohol content when unable to wash hands.
- Educating people about covering their nose and mouth when they sneeze or cough.
- Self-isolating at the appearance of even the mildest symptoms of COVID-19.
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