COVID-19

COVID-19 infection may be asymptomatic or show up as mild to moderate and severe symptoms. It takes up to 14 days for the symptoms of the infection to show. The most common symptoms of a COVID-19 include:

• Fever
• Cough (usually dry but may also be wet or chesty later on)
• Shortness of breath
• Loss of smell and taste

Depending on the severity of the infection, COVID-19 symptoms may vary. Headaches, sore throat, sneezing, fatigue, muscle pain, runny nose and congestion has been seen in some patients. In rare cases, coronavirus can cause pink eye. Other symptoms include:

• Gastrointestinal symptoms like stomach cramps, diarrhoea, vomiting and nausea.
• Pneumonia
• Wheezing 
• Central cyanosis (bluish discolouration of the tongue and lips)
• Shock
• Lung fibrosis
• Multi-organ failure and death

COVID-19 is caused by the virus SARS-COV-2, a member of the coronavirus family. It is a zoonotic infection (jumped from animals to humans) related to the Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS) viruses - SARS caused an epidemic in the year 2002-03 affecting about 26 countries and MERS has caused outbreaks in South Korea and the Middle East in the previous decade.

Studies show that the virus mainly binds to a receptor known as ACE 2, which is present abundantly in the lungs, heart and intestines - to gain entry into body cells. Hence, predominantly respiratory symptoms and gastrointestinal symptoms are seen in this infection.

Normally, ACE2 binds to an enzyme called angiotensin-converting enzyme II. This enzyme is a part of a system called RAAS (Renin-angiotensin-aldosterone- System) which plays an important role in maintaining electrolyte balance and blood pressure in the body.

Read more: Role of ACE2 receptors in COVID-19

As the virus enters the body, it elicits strong immune responses that lead to release of inflammatory molecules - cytokines and chemokines in the body. These chemicals recruit more cells that specialise in fighting viruses. Since viruses live inside body cells, the immune system destroys all the affected cells to get rid of the virus. Cytokine storm, a condition marked by high levels of cytokines has been found to be the cause of severe cases of COVID-19 and lung damage.

Read more: COVID-19 and inflammation

Risk factors: Those with chronic diseases (diabetes and heart diseases, for example), immunocompromised people, the elderly (above 60 years of age) and babies (under the age of 5) are most at risk of getting severe COVID-19. However, the disease affects people of every age.

Read more: What pregnant women need to know about COVID-19

Since COVID-19 first showed up in the Wuhan wet market, it is believed that it has jumped from animals to humans - SARS and MERS are also zoonotic infections that have bats and camels as animal reservoir hosts, respectively. Here is what is known about the transmission of COVID-19:

Animal to human: So far, not much is known about the animal host of COVID-19. Various animals have been considered as the likely host. At first, snakes were considered to be the source of the virus, however, experts suggested that since snakes are reptiles, SARS-COV-2 could not have jumped directly to humans (a mammal). The DNA of a bat coronavirus is 96% similar to the virus that causes COVID-19 infection in humans. However, the DNA of the bat COVID-19 virus has two sites that would have prevented it from binding to receptors in the human body.

This brought up the idea of a possible intermediate host. Pangolins were thought to be an intermediate host. But these scaly mammals have even fewer similarities to the SARS-COV-2 virus and hence could not be an ideal intermediate host. Some experts believe that the virus may have mutated inside the human body while it was silently being transmitted.

Human to human transmission: Human to human transmission of coronavirus occurs through coughing, sneezing and coming in direct contact with the affected person. Close contact is defined as: 

• Living in the same house as the infected person.
• Sitting or spending a lot of time near the patient at work.
• Travelling with the patient in the same vehicle.
• Caring for the patient.

SARS-COV-2 stays in the air for up to three hours and on various surfaces for varied periods of time. According to the scientists at the University of California, this virus can be detected on cardboard for up to one day, on copper for up to four hours and on steel and plastic for about three days.

Read more: What is droplet transmission?

Most health authorities have recognised that the virus has four stages of transmission in a new area. These include:

• Stage 1: Imported transmission - new cases are imported from areas that are already affected by the disease. 
• Stage 2: Local transmission - some people who come in contact with the imported cases also show symptoms. This is mostly seen in family members or close contacts but can be anybody who comes in contact with the infected person can get it.
• Stage 3: Community transmission - new cases arise in people with no known link to any previously infected people and no history of travel to the affected area.
• Stage 4: Epidemic - the disease spreads to a large number of people and a lot of new cases show up everyday. This is what happened in China and Italy.

COVID-19 is diagnosed through both serological testing (blood tests) and nucleic acid sequencing (RT-PCR test).

• Serological testing involves the isolation of at least two different blood specimens at specific intervals - the first one in the first week and the next one in week 2 to 3 after the suspected patient starts showing symptoms. It is mostly done to check if a person’s body is responding to the virus (produces an immune response). Read more: ELISA antibody test for COVID-19
• Nucleic acid sequencing is done through reverse polymerase chain reaction (RT-PCR), in which the nucleic acid (RNA) of the virus is isolated through nasal or oropharyngeal swabs and is amplified in the lab to check if it has the virus. To do this test, a trained medical professional will use a swab to collect samples from the suspected patient's nose and mouth.
• Sputum and urine are taken in certain cases to obtain tissue samples for testing.
• A lung biopsy may be done in severe illnesses.
• A CT scan may be done to check if and how much your lungs are affected.

Currently, there is no treatment for COVID-19; symptomatic management remains the only option.

Mild cases generally do not require treatment, though if you have fever or cough, your doctor may give you some medications to prevent the symptoms from worsening.

Physicians suggest taking ample fluids (to maintain your fluid balance) and take rest to tide over mild illness. Also, make sure to isolate yourself from the people around you. The World Health Organization recommends staying at least 3 feet away from anybody who shows symptoms of cough and fever. Also wear a mask or face cover to avoid contaminating surfaces.

Read more: How long does SARS-COV-2 survive on various surfaces

Antiviral drugs such as lopinavir/ritonavir are suggested in certain cases to suppress the growth of the virus. Though antivirals don’t kill the virus, they give your immune system an upper hand over the virus so it can eliminate the infection from the body. That said, these drugs have other side-effects and they should not be taken unless absolutely necessary. Hydroxychloroquine is also found to be effective in improving symptoms of non-severe COVID-19. However, more studies need to be done to confirm the safety as well as benefits of hydroxychloroquine for COVID-19 patients. RAAS inhibitors or blockers are also given to treat patients with comorbidities.  

Read more: Is hydroxychloroquine really effective against COVID-19

The Ministry of Health and Family Welfare has put the following guidelines for the treatment of a COVID-19 patient:

• Oxygen therapy is given in cases of hypoxia, shock and breathing difficulties. 
• If the patient is not in shock, he/she is monitored and is given intravenous fluids. Fluid administration is done carefully as it may worsen the patient’s condition if done aggressively.
• In case of sepsis, antimicrobials are given to treat all the possible causes of respiratory illness even when the patient is suspected of COVID-19. The antibiotics are chosen on the basis of possible causes of pneumonia
• Systemic corticosteroids should not be given to control pneumonia unless they are needed for some other reason.
• The patient has to be put on ventilator support in severe cases. Read more: Must-have features in ventilators for severe COVID-19 patients 
• For people with co-morbid conditions, the treatment is tailored around their conditions. The physician decides if some chronic therapies (therapies a patient is already getting for their existing condition) need to be changed. Co-morbidity simply refers to having more than one health problem at a time. Chronic diseases are ailments like diabetes and high blood pressure that are managed by being on medication for life.

In the absence of vaccines or treatment, prevention remains the best way to manage COVID-19. Most preventive measures focus on social distancing along with certain personal hygiene practices to reduce the risk of exposure to the virus. The World Health Organization (WHO) lists the following recommendations for the prevention of COVID-19:

• Avoid public gatherings or crowded places, especially if you are above 60 years of age, are immunocompromised or suffer from a chronic illness.
• Stay at home whenever you can and avoid all non-essential travel. 
• Maintain a distance of at least 3 feet (one metre) from anybody who shows signs of active infection including sneezing or coughing. 
• Wash your hands with soap and water for at least 20 seconds. 
• When soap and water is not available, use alcohol-based sanitisers (with at least 60% alcohol). However, washing your hands is better than sanitising as it clears more microbes than sanitisers. Also, sanitising won’t help much if your hands are dirty. Read more: How to make a hand sanitizer at home
• Do not touch your face, nose or mouth as the virus spreads through direct contact.
• Do not cough or sneeze into your palm. Instead, do it in the bend of your elbow or on a tissue. Throw away the tissue properly after use - in a dustbin.
• Try to be physically active even at home. Regular exercise keeps up the body’s functioning well and helps to deal with the anxiety of living through a pandemic.

Since older adults are most at risk of COVID-19, the following tips are suggested for them in addition to the general prevention steps:

• Stock up on essential supplies so they don’t have to frequently go out to the market.
• The Centers for Disease Control and Prevention, USA, suggests that older adults should maintain a distance of at least 6 feet from any sick person. 
• Frequently clean and disinfect all the surfaces in your house.
• Have an emergency contact list and be in touch with your loved ones if you live alone.
• Even if you show symptoms, try not to panic and contact your doctor as soon as you can.

If you are suffering from a chronic illness:

• Avoid going to the hospital if you can. Instead, talk to your doctor on the phone or schedule an appointment if you must. This will further reduce your risk of being exposed to the infected people.
• Also, keep all your essential medicines in stock to avoid extra trips to the pharmacy and do not skip any medications to keep up your health.

Read more: COVID-19 prevention tips for older people and those with chronic illness 

Tips for children

Children are usually not as severely affected by coronavirus as adults. Though, it is best to follow the same precautionary measures for children as well.

• Teach good hygiene practices to your kids such as to sneeze or cough into a tissue and throw the tissue after every use.
• Wash their toys and soft toys in warm water (as warm as possible) and make sure they are dry completely before you give them back to the children.

Read more: COVID-19 prevention tips for parents with young children