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How Does Coronavirus Spread?

World map showing covid-19 spreading
by: Adam Singfield
January 4, 2024

The spread of COVID-19 has become a global concern, and understanding how the virus spreads is crucial in containing its transmission.

Here are the scientific details of how the coronavirus spreads from one person to another.

What is COVID-19?

According to the World Health Organization (WHO), COVID-19, short for Coronavirus Disease 2019, is a highly contagious respiratory illness caused by the SARS-CoV-2 virus. It originated in late 2019 and has since spread globally, resulting in a pandemic.

The symptoms of an infected person range from mild to severe, with some individuals experiencing no symptoms at all. Common symptoms include:

  • Fever
  • Cough
  • Difficulty breathing

It is essential to note that COVID-19 can lead to severe illness and even death, particularly among older adults and individuals with underlying health conditions, such as immunocompromised individuals.

Person-to-person transmission

When the pandemic started, the most common question was, “How does COVID spread from one person to another?”

Later, WHO and the Centers for Disease Control and Prevention (CDC) announced that the primary mode of COVID-19 transmission is close contact with an infected person.

When an infected person breathes out, coughs, sneezes or talks, they release tiny droplets containing the virus. These droplets can be inhaled by nearby individuals, leading to infection.

Other ways that the virus can spread include:

  • Catching respiratory droplets on contaminated surfaces and objects, which can serve as a potential source of transmission if touched
  • Airborne transmission, particularly in enclosed spaces with poor ventilation
  • Exposure to aerosols from a sick person, which can linger in the air for extended periods

Community spread

SARS-CoV-2, the virus that causes COVID, lives for about 20 minutes in the open air, but aerosols can survive for up to three hours. This puts the community at an increased risk of getting the disease, especially in a closed area without proper ventilation.

When an infected person coughs, they can unknowingly spread the virus to others, making it challenging to trace and contain the source of infection.

Public health officials play a critical role in identifying and managing community spread through:

  • Contact tracing
  • Testing
  • Implementing preventive measures, such as:
    • Social distancing
    • Wearing face masks
    • Disinfecting frequently touched surfaces

Pets and COVID-19

While the primary mode of transmission is person-to-person, there have been rare instances of pets being infected with the SARS-CoV-2 virus. However, the risk of pets spreading the virus to humans is considered low.

Practicing good hygiene when interacting with pets, such as washing hands before and after contact, is still advisable. If you have COVID-19, limit close contact with pets to prevent potential transmission.

How easy is it to get infected?

You’re more likely to get infected with COVID-19 if you:

  • Have close contact with a person who has recently tested positive
  • Have brief encounters or are in the same vicinity with an infected person
  • Spend time in crowded indoor settings, especially without proper ventilation

Can I get infected from delivery food, packages or groceries?

The risk of contracting COVID-19 from food, packages or groceries is considered low. The primary mode of transmission is through respiratory droplets and close contact with infected individuals.

However, there’s still a high risk of getting infected if the person delivering the items is infected.

Practicing good hygiene by washing hands before and after handling food or packages. Also, maintain proper food safety measures, such as cooking food thoroughly, to help reduce any potential risk.

How to protect yourself

Woman standing in front of the window wearing her mask. Appears to be in isolation.

Protecting yourself and others from COVID-19 requires a combination of preventive measures. These include:


Although breakthrough infections may still occur despite your vaccination status, COVID-19 vaccines have been proven to be highly effective in preventing severe disease and reducing the risk of transmission. Research shows that a fully vaccinated individual has a stronger immune system against the virus. It is essential to follow national institutes or CDC guidelines and get vaccinated when eligible.

Face masks

Wearing a well-fitting face mask indoors or in crowded areas can significantly reduce the spread of respiratory droplets and particles. A well-fitting mask prevents infected people from exhaling small droplets, which inhibits them from contaminating surfaces.

Hand hygiene

Regularly washing hands with soap and water for at least 20 seconds or using hand sanitizers containing at least 60% alcohol is crucial in preventing the transmission of the virus. This is highly suggested if you take public transportation or in large gatherings.

Social distancing

Maintaining a safe distance of at least 6 feet (2 meters) from others, especially in public spaces, helps minimize close contact and reduces the risk of transmission.

When to quarantine or isolate

Quarantine is recommended for individuals in close contact with someone infected, while isolation is for those who have tested positive or are experiencing symptoms.

The duration of quarantine and isolation may vary based on guidelines provided by local health authorities. Following these guidelines and avoiding contact with others are important to prevent further transmission.

COVID-19 vaccines help stop COVID-19

COVID-19 vaccines have played a pivotal role in controlling the spread of the virus. Extensive research and rigorous testing have shown that vaccines effectively prevent severe illness, hospitalization and death.

Vaccinated individuals are also less likely to transmit the virus to others. Vaccines and other preventive measures, such as wearing masks and practicing good hand hygiene, provide the best defense against COVID-19.

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