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Coronavirus Disease


CoronaVirus Disease, also known as COVID-19, is caused by a novel coronavirus called Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The organism was first identified after an outbreak of respiratory illness at Wuhan, China, in 2019. Soon it started spreading to other parts of the world, and on March 11, 2020, it was declared a global pandemic by the World Health Organization (WHO). New variants of the SARS-CoV-2 virus have emerged, such as Omicron, Delta, and Alpha. These variants are more transmissible and can evade some of the protection offered by vaccines. It is therefore important to stay up-to-date on the latest information about COVID-19 variants and to get vaccinated and boosted as soon as possible.


The Causative Organism of this disease is the coronavirus. Coronaviruses are called so because of crown-shaped spikes on their surface. There are four main subgroups of these viruses, alpha, beta, gamma, and delta. The human coronaviruses are alpha and beta types. COVID-19 is caused by a novel virus called Severe Acute Respiratory Syndrome CoronaVirus type 2 (SARS-CoV-2).

Route of Transmission

The main route of transmission is via droplets carrying the infectious virus. Other ways include contact transmission such as shaking hands, hugging, etc., and airborne transmission through suspended droplets in the air. The CDC recommends wearing a mask indoors in public and outside in busy locations or when in close contact with unvaccinated people if you live in an area where there have been a lot of new COVID-19 cases in the recent week.

Risk Factors and Epidemiology

According to WHO, the total number of COVID-19 infected individuals worldwide is over 760 million, with 6.8 million casualties. The United States reported the most significant number of Covid cases and the highest number of deaths so far in the world.

Risk factors for the disease include:

  • People living in areas with high local transmission
  • Healthcare workers that come in close contact with infected individuals
  • People traveling to and from areas where there is the regional spread of infection
  • Certain illnesses and conditions are associated with an increased risk of COVID-19. These include cancer, COPD, kidney diseases, cerebrovascular diseases, coronary artery disease, diabetes, dementia immunocompromised state, obesity, smoking, and pregnancy.
  • Comorbidities such as hypertension, asthma, liver disease, etc.

Signs and Symptoms

The incubation period for COVID-19 varies greatly, ranging from two days to two weeks. Some cases are maybe asymptomatic. Most patients develop only mild symptoms, whereas few progress to severe disease with complications. Signs and symptoms include:

  • Fever or chills
  • Cough
  • Shortness of breath
  • Fatigue
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea

Sometimes malaise, sputum production, respiratory distress, and neurologic symptoms are also noted. The most common manifestation of COVID-19 is pneumonia. Complications include:

Differential Diagnosis

The initial symptoms of COVID-19 are non-specific and mimic many other respiratory infections. These could be viral or bacterial and include:

  • Viral infections are caused by influenza, parainfluenza, human rhinovirus, adenovirus, and respiratory syncytial virus.
  • Bacterial respiratory infections include Hemophilus influenza pneumonia and streptococcus pneumonia.
  • Atypical pneumonia such as legionellosis and mycoplasma pneumonia.


For a definitive diagnosis, PCR antigen testing is required. Supplemental labs include:

  • Complete blood count with inflammatory markers such as CRP & ESR
  • Lactate dehydrogenase levels
  • Ferritin levels
  • D-dimers
  • Chest X-ray
  • High-resolution CT (HRCT) chest
  • A Rapid antibody test (RAT) can be used to detect the presence of antibodies against COVID-19. It is much less sensitive than the PCR test.

Treatment and Medications

The mainstay of treatment is to provide supportive care to all infected patients and prevent complications. An effective therapy against the disease is still under process as a lot of therapy is being done on an experimental basis only.

  • The first drug to gain popularity for COVID-19 treatment was Remade Sivir, an antiviral drug. It is used mainly to treat hospitalized individuals and older age groups with declined lung function.
  • Convalescent plasma, monoclonal antibodies, kinase inhibitors, interferons, and interleukin inhibitors are also being used actively to treat COVID-19.
  • Corticosteroids with supplemental oxygen are used in hospitalized patients on ventilators.
  • Macrolides are used to fight secondary bacterial respiratory infections.
  • Nitric oxide- inhaled nitric oxide has also been used for poor lung function and ventilated patients who develop acute respiratory distress syndrome. The costs associated with this treatment are very high.
  • Statins- in addition to decreasing cholesterol levels, also reduce the inflammatory process of atherosclerosis. However, their role in treating COVID-19 is still not very well established.
  • Adjunctive nutritional therapies with zinc, vitamin D, and vitamin C are recommended.
  • The first vaccine against the COVID-19 virus was developed in August 2021 by Pfizer and gained full FDA approval. After that, various other commercial forms worldwide have also been manufactured, including Moderna, Johnson & Johnson, Sputnik-V, etc. all of these are mRNA vaccines with varying efficacy ranging between 70-98%. These are given in two doses usually and work by imparting passive immunity.

A vaccine can prevent you from getting the COVID-19 virus or keep you from becoming extremely ill if you do get it. Furthermore, vaccinated against COVID-19 may provide better protection than getting sick with COVID-19. According to a recent study, unvaccinated people who have already been infected with COVID-19 are more than twice as likely to become infected with COVID-19 than fully vaccinated people.

Furthermore, if you are fully vaccinated, you will be able to resume many activities that you may have been unable to accomplish due to the pandemic. The CDC recommends wearing a mask indoors in public and outside in busy locations or when in close contact with unvaccinated people if you live in an area where there have been a lot of new COVID-19 cases in the recent week. You may need to remain wearing a mask even if you are entirely vaccinated and have a condition or are taking medications that weaken your immune system.

For patients who have been fully vaccinated but have not had a strong enough immunological response, an additional dose of the COVID-19 vaccine is recommended.


According to WHO, the incidence of death in populations by age indicated that death rates are highest amongst males and older individuals. Hospitalization and death rates are highest amongst individuals with comorbid conditions, specifically diabetes, hypertension, obesity, and cardiac diseases.


General methods of prevention include:

  • Hand hygiene- handwashing with soaps for at least 20 seconds and using alcohol-based sanitizers is recommended.
  • Avoid touching your eyes, nose, and mouth with unwashed hands.
  • Avoid close contact with infected individuals.
  • If you are sick or feel you have developed symptoms of the disease, get tested immediately and avoid going to your workplace, school, etc., to prevent the transmission of the disease.
  • Cleaning of frequently touched objects and surfaces with disinfectants.
  • Wear face masks while going out of the house to avoid information through infected droplets that can enter your body through the nose and mouth.
  • Practice social distancing in public places. Stay at least six feet apart from people in public places.
  • At-risk individuals, including the elderly, people with comorbid conditions, and healthcare workers, should exercise extra precautions. Healthcare workers should wear proper gear when contacting highly infected individuals.
  • Post-exposure prophylaxis includes self-monitoring for fever, cough, shortness of breath, and related symptoms with at least two weeks of self-quarantine. The same goes for international travelers.
  • All the preventive measures mentioned above and the vaccine provide pre-exposure prophylaxis.

The CDC recommends additional COVID-19 vaccine doses and booster doses in the following situations:

Additional Dose: The CDC recommends the third dosage of an mRNA COVID-19 vaccination for selected people with weakened immune systems, such as those with an organ transplant. After two doses of an mRNA COVID-19 vaccine, those with compromised immune systems may not generate enough immunity, and an additional amount may boost their COVID-19 protection.

Booster Dose: You should have a single booster dose if you are 18 or older, have received both doses of the Pfizer-BioNTech COVID-19 vaccine or the Moderna COVID-19 vaccine, and it has been at least six months.

If you are 18 or older and have already received one dose of the Janssen/Johnson & Johnson COVID-19 vaccine, you should receive a single booster dose. If you are 18 or older and have received both doses of the Pfizer-BioNTech COVID-19 vaccine or the Moderna COVID-19 vaccine, and it has been at least six months, you should have a single booster dose. Booster doses can help to boost immunity and protect against severe disease

A booster dose may also be given to pregnant women. You have a choice in which vaccine you receive as a booster shot. You can receive a booster dose from the same brand as your last shot or shots, or you can get one from a different brand.

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on June 22, 2023.



Coronavirus (who.int)


A Review of Coronavirus Disease-2019 (COVID-19) | SpringerLink


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