• Wed. Jun 29th, 2022

Coronaviruses are a large group of viruses that cause diseases in animals and human beings. They are often spread among bats, cats, and camels and can sometimes infect people.

In animals, coronaviruses can cause diarrhea in pigs and cows, and upper respiratory disease in chickens. In human beings, the viruses can cause mild respiratory infections, like the common cold, but can lead to serious illnesses, like pneumonia.

Coronaviruses are called for the crown-like spikes on their surface. Human coronaviruses were first specified in the mid-1960s. They are closely monitored by public health officials.

Novel Coronavirus (COVID-19)

The novel coronavirus (SARS-CoV-2) that causes COVID-19 first emerged in the Chinese city of Wuhan in 2019 and was announced a pandemic by the World Health Organization (WHO). In December 2020, the US launched a national vaccination campaign. There are steps you can take to help stop the spread of COVID-19.


Symptoms of coronavirus disease 2019 (COVID-19) may seem 2 to 14 days after disclosure. This time after exposure and before having symptoms is called the gestation period. You can spread COVID-19 (presymptomatic transmission) before you have symptoms. Common symptoms can include:

  • Fever
  • Cough
  • Tiredness

Early symptoms of COVID-19 may include a loss of taste or smell.

Other symptoms include:

  • Headache
  • Shortness of breath or difficulty breathing
  • Muscle aches
  • Colds
  • Runny nose
  • Throat pain
  • Chest pain
  • Pink eye (conjunctivitis)
  • Nausea
  • Vomiting
  • Diarrhea
  • Rash

This list is not exhaustive. Children have the same symptoms as adults and generally have milder illnesses.

The severity of COVID-19 symptoms can range from mild to severe. Some people have only a few symptoms. Some may have no symptoms at all, but may still be contagious (presymptomatic transmission). One week after the onset of symptoms, some people may experience worsening symptoms such as shortness of breath and pneumonia.

Some people experience COVID-19 symptoms for more than four weeks. These health problems are sometimes called post-COVID-19 conditions. Some children experience multisystem inflammatory syndrome, a syndrome that affects certain organs and tissues, a few weeks after receiving Covit-19. Rarely, do some adults also experience this syndrome.

The elderly have a higher risk of developing serious illnesses from COVID-19, and the risk increases with age. People who already have medical conditions may also have a higher risk of serious illness. The following are some medical conditions that may increase the risk of serious illness from COVID-19:

  • Severe heart diseases such as heart failure, coronary artery disease, or cardiomyopathy
  • Cancer
  • Chronic obstructive pulmonary disease (COPD)
  • Type 1 or type 2 diabetes
  • Overweight, obese, or severe obesity
  • High blood pressure
  • Smoking
  • Chronic kidney disease
  • Sickle cell disease or thalassemia
  • Weakened immune system by solid organ transplant or bone marrow transplant surgery
  • Gestation
  • Asthma
  • Chronic lung diseases such as cystic fibrosis or pulmonary hypertension
  • Liver disease
  • Dementia
  • Down syndrome
  • Bone marrow transplant surgery weakened immunity to HIV or certain medications
  • Brain and nervous system conditions, such as strokes
  • Substance use disorders

This list is not complete. Other medical conditions may increase your risk of serious illness from COVID-19.


An acute respiratory syndrome is caused by infection with coronavirus 2 or SARS-CoV-2, coronavirus disease 2019 (COVID-19).

The virus that causes COVID-19 is easily spread among the population. Data show that the COVID-19 virus mainly spreads from person to person within close contact (within about 6 feet or 2 meters). The virus is spread by droplets released by an infected person when they cough, sneeze, breathe, sing or speak. These droplets can be inhaled or injected into the mouth, nose, or eyes of a nearby person.

The COVID-19 virus can sometimes be spread when a person is exposed to tiny droplets or aerosols in the air for several minutes or hours – this is called airborne transmission.

The virus is spread by touching the surface of the virus and then touching your mouth, nose, or eyes. But the risk is low.

The COVID-19 virus can be transmitted from one person to another but has not yet developed symptoms. This is called presymptomatic transmission.

It is possible to get COVID-19 twice or more, but this is unusual.

If a virus has one or more new mutations, it is called a variant of the original virus. The CDC has identified two variants of the virus that causes COVID-19 as variants of concern. These include the Delta (p.1.617.2) variant and the Omicron (p.1.1.529) variant. The delta variant is more contagious than earlier variants and might cause more severe disease. The Omicron variant is more easily transmitted than other types, including delta. But it is not yet clear whether Omicron will cause the most serious disease

Risk factors

Risk factors for COVID-19 seem to include:

  • Close contact (within 6 feet, or 2 meters) with a person who has COVID-19
  • Being coughed or sneezed on by an infected person

When to see a doctor

If you have COVID-19  symptoms or you’ve been in contact with someone diagnosed with COVID-19, contact your health care provider right away for medical advice. Your healthcare provider may recommend a COVID-19 test. If you have emergency COVID-19 symptoms such as difficulty breathing, seek treatment immediately. If you need to go to the hospital, call in advance so health care providers can take action to ensure that others are not exposed.

If you have emergency COVID-19 symptoms, seek care immediately. Emergency symptoms can include:

  • Breathing trouble
  • Persistent chest pain or pressure
  • Inability to stay awake
  • New confusion
  • Pale, gray, or blue-colored skin, lips, or nail beds — depending on skin tone

This list is not complete. Tell your healthcare provider if you are elderly or have a chronic medical condition such as heart disease or lung disease because you are at high risk of developing COVID-19.