Corona virus

Coronavirus disease (COVID-19) is an infectious disease caused by the SARS-CoV-2 virus.

The initial case of the disease was detected in Wuhan, China, in December 2019. The majority of scientists agree that the SARS-CoV-2 virus likely entered human populations through natural zoonosis, similar to the outbreaks of SARS-CoV-1 and MERS-CoV, and consistent with other historical pandemics. Social and environmental factors, such as climate change, ecosystem destruction, and wildlife trade, heightened the risk of zoonotic spillover. The disease rapidly spread across the globe, leading to the COVID-19 pandemic.

Spread

The disease is caused by the SARS-CoV-2 virus, which spreads between people in several different ways.

Current evidence indicates it mainly spreads between people in close contact, like during conversations. The virus can be transmitted from an infected person’s mouth or nose through small liquid particles when they cough, sneeze, speak, sing, or breathe. Another person can contract the virus by inhaling these particles at short range (short-range aerosol transmission) or if the particles come into direct contact with the eyes, nose, or mouth (droplet transmission).

The virus can also spread in poorly ventilated or crowded indoor settings, where aerosols can linger in the air or travel farther (long-range aerosol transmission). Additionally, people may become infected by touching their eyes, nose, or mouth after contacting contaminated surfaces or objects.

symptoms

Individuals with COVID-19 have experienced a variety of symptoms, ranging from mild to severe. Symptoms can manifest 2-14 days after being exposed to the virus. Anyone can exhibit symptoms of varying intensity. Potential symptoms include:

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhoea

Individuals exhibiting the following symptoms should seek immediate medical attention:

  • Difficulty breathing, especially at rest, or inability to speak in sentences
  • Confusion
  • Drowsiness or loss of consciousness
  • Persistent pain or pressure in the chest
  • Skin becoming cold or clammy, or turning pale or bluish in colour
  • Loss of speech or movement

Diagnosis/ testing

  • PCR Tests

PCR tests are considered the “gold standard” for COVID-19 testing. As a type of nucleic acid amplification test (NAAT), they are more accurate at detecting the virus than antigen tests. Typically, a healthcare provider collects the sample, which is then sent to a laboratory for analysis. Results may take up to 3 days.

  • Antigen Tests

Antigen tests are rapid tests that usually provide results within 15-30 minutes. Positive results from antigen tests are reliable. However, antigen tests are generally less sensitive than PCR tests, especially in asymptomatic individuals. Thus, a single negative antigen test cannot definitively rule out infection. The FDA recommends two negative antigen tests for symptomatic individuals or three for asymptomatic individuals, performed 48 hours apart, to be confident you do not have COVID-19. A single PCR test can confirm an antigen test result.

Understanding Test Results

  • Positive COVID-19 PCR or Antigen Test: A positive result almost certainly means you have COVID-19, and no further testing is needed.
  • Negative PCR Test: A negative result most likely indicates you do not have COVID-19.
  • Negative Antigen Test: The FDA recommends repeating an antigen test two days after the initial test, whether you have symptoms or not, to ensure an accurate diagnosis.

If you test positive, contact a healthcare professional immediately to discuss available options.

Complications 

Complications of COVID-19 can be severe and diverse. They may include pneumonia, acute respiratory distress syndrome (ARDS), multi-organ failure, septic shock, and potentially death. Cardiovascular complications such as heart failure, arrhythmias like atrial fibrillation, myocarditis, and thrombosis, especially venous thromboembolism, are also documented. Liver injury, indicated by elevated liver enzymes, occurs in about 20-30% of COVID-19 cases.

Neurological effects can involve seizures, strokes, encephalitis, and Guillain–Barré syndrome, resulting in loss of motor function. Children may develop a condition resembling Kawasaki disease called paediatric multisystem inflammatory syndrome, which can be fatal. Acute encephalopathy, though rare, has been reported in some COVID-19 patients with altered mental status.

Treatment

A significant number of individuals with COVID-19 recuperate at home without requiring medication administered by a healthcare professional. Symptoms can often be alleviated with:

  • Fever reducers
  • Pain relievers like ibuprofen (Advil, Motrin IB, others) or acetaminophen (Tylenol, others).
  • Cough medicine.
  • Staying hydrated by drinking plenty of water
  • Getting adequate rest to support the body’s recovery from the virus

Your healthcare provider may recommend medications to treat COVID-19 if you test positive and are at high risk of severe illness. These medicines can help prevent mild illness from worsening and may include:

  • Nirmatrelvir-ritonavir (Paxlovid): This combination therapy blocks an enzyme that the COVID-19 virus needs to replicate. It is approved for mild to moderate COVID-19 in individuals aged 12 and older at higher risk. Paxlovid is taken orally as a pill.
  • Remdesivir (Veklury): Remdesivir inhibits the virus from spreading in the body and is used to treat COVID-19 in individuals aged 12 and older. It is administered intravenously (IV), directly into a vein.
  • Molnupiravir (Lagevrio): Molnupiravir, authorized by the FDA, treats mild to moderate COVID-19 in adults at higher risk who cannot use other treatments. It is taken orally as a pill.

prevention

People should get vaccinated as soon as they are eligible and follow local vaccination guidelines to protect themselves from COVID-19. The vaccines offer strong protection against severe illness, hospitalisation, and death.

To prevent the spread of COVID-19:

  • Avoid crowds and maintain a safe distance from others, even if they appear healthy.
  • Wear a properly fitted mask if you feel unwell, have been in contact with sick individuals, are at high risk, or are in crowded or poorly ventilated areas.
  • Frequently clean your hands with an alcohol-based hand rub or soap and water.
  • Cover your mouth and nose with your elbow or a tissue when coughing or sneezing.
  • Dispose of used tissues immediately and wash your hands afterward.
  • If you develop symptoms or test positive for COVID-19, self-isolate until you recover.

Vaccination

Initially, the focus of SARS-CoV-2 vaccines was on preventing symptomatic and severe illness. The first COVID‑19 vaccines became available to the public under emergency authorizations and conditional approvals. Most vaccines required two doses, though single-dose options like the Janssen COVID‑19 vaccine and three-dose schedules such as Razi Cov Pars and Soberana were also introduced. However, vaccine effectiveness has shown to decrease over time, necessitating booster doses to sustain protection against COVID‑19.

COVID‑19 vaccines are widely acknowledged for their role in reducing the transmission and severity of COVID‑19, as well as lowering mortality rates. Common side effects of COVID‑19 vaccines include temporary soreness, redness, rash, or inflammation at the injection site, as well as fatigue, headache, muscle pain (myalgia), and joint pain (arthralgia). These symptoms typically resolve on their own within a few days and generally do not require medical intervention.COVID‑19 vaccination is considered safe for individuals who are pregnant or breastfeeding.

Two categories of COVID-19 vaccines are approved or authorized in the United States. include:

     1.mRNA COVID-19 vaccines

The Pfizer-BioNTech and Moderna COVID-19 vaccines belong to the category of mRNA vaccines. These vaccines use messenger RNA (mRNA) synthesized in a lab to instruct cells to produce a protein, or a fragment of a protein, which then stimulates an immune response in the body. The mRNA from these vaccines is typically broken down and eliminated from the body within a few days after vaccination.

  • The Pfizer-BioNTech COVID-19 Vaccine (2023–2024 Formula) is authorized for children aged 6 months to 11 years. COMIRNATY is the licensed Pfizer-BioNTech product for individuals aged 12 years and older.
  • Similarly, the Moderna COVID-19 Vaccine (2023–2024 Formula) is authorized for children aged 6 months to 11 years. SPIKE VAX is a licensed Moderna product for individuals aged 12 years and older.

      2.protein subunit vaccine

The Novavax COVID-19 vaccine is classified as a protein subunit vaccine. These vaccines contain fragments (proteins) derived from the virus that causes COVID-19, specifically the spike protein. The Novavax vaccine also includes an adjuvant, which enhances the immune system’s response to the spike protein. Once the immune system learns to recognize and respond to the spike protein, it can quickly react to the actual virus and provide protection against COVID-19.