How you get infected
You can become ill if you are infected with SARS-CoV2, the virus that causes COVID-19. The virus enters your body through your respiratory system (nose, mouth and airways). Your body tries to prevent viruses from invading and spreading. Your immune system is part of how your body defends itself. A pathogen has to get past that defence before it can make you ill. For that reason, a single virus particle is rarely enough to make you sick. You will (usually) have to come into contact with many virus particles before you become ill.
A person who has COVID-19 produces millions of copies of the virus inside their body. These virus particles are found in large quantities in the lungs, but also in other ‘moist’ parts of your body, such as your throat or nasal cavity. When you shout, sneeze or cough, you are not just pushing out air: lots of droplets also come out of your lungs, throat or nasal cavity. The coronavirus SARS-CoV-2 spreads through these droplets. These droplets can transmit the virus to others, especially during close contact at a distance of less than 1.5 meters. You could become infected by:
- Inhaling the tiny droplets
- Getting droplets in your eyes, nose or mouth, for example if an infected person coughs or sneezes near you
- Touching your eyes, nose or mouth after getting the SARS-CoV-2 virus on your hands
More distance reduces the risk of infection
The risk that you will be infected is highest if you are close to someone who has the coronavirus. In principle, more distance reduces the risk of infection. This is because larger droplets do not travel as far. In addition, smaller droplets disperse and are less concentrated over a greater distance. Good ventilation that refreshes the air inside the room can also help prevent the virus from spreading.
Under certain conditions, the virus can travel farther, carried in aerosolised droplets that are tiny enough to float in the air, and infect people at greater distances. This could happen in rooms that have little to no ventilation and/or where many people are gathered, especially for extended time periods. Transmission of the SARS-CoV-2 virus via ventilation shafts and air ducts has not been observed.
Sometimes high concentrations of aerosolised droplets are released into the air in a burst, such as when ICU patients are connected to medical ventilators to help them breathe. That is why there are stricter requirements for equipment used by ICU staff, such as face masks.
Although concentrations are much lower than in an ICU, large quantities of small aerosolised droplets can also be released during singing or sports. There are indications that singing could pose an increased risk of spreading SARS-CoV-2. For that reason, the Outbreak Management Team (OMT) issued an advisory opinion in November 2020 on singing in a choir.
It seems unlikely that the coronavirus SARS-CoV-2 is spread via parcels or surfaces (such as a door, shopping cart or keyboard). Although it has been demonstrated in the laboratory that this is possible, that experiment was done under ideal conditions that will rarely occur in actual practice. The most important thing is: minimise your risk and wash your hands regularly with soap and water.
Distancing reduces the risk of infection
Distancing reduces the risk that people will infect each other and prevents the coronavirus from spreading. It is known that most droplets that are released during coughing or sneezing do not travel further than 1 to 2 metres. An article in medical journal The Lancet stated that the policy of staying at least 1 metre apart was effective, but stated that 2 metres might be better, although there was no clear evidence to support this at that time. Countries interpret this information differently. That is why 1 metre is the rule in some countries (such as Denmark and China), while others require 2 metres (such as Spain and the United Kingdom), and some countries have advised a minimum distance of 1.5 metres (the Netherlands, Australia, Belgium).
How to prevent the coronavirus SARS-CoV-2 from spreading
- Get vaccinated. This reduces the risk that you will feel poorly or become seriously ill.
- Stay 1.5 metres (2 arm lengths) apart from others. Even though it is no longer compulsory in most places, keeping your distance reduces the risk of infection.
- If you have symptoms, stay home and get tested
- Avoid busy places and crowded rooms. If you are in an indoor space with lots of people, the risk of infection increases.
- Always ensure effective ventilation in your home and workplace, 24 hours a day. More information about ventilation can be found on Government.nl or on the RIVMNational Institute for Public Health and the Environment page on Ventilation.
- Wash your hands with soap and water. This will remove the virus from your hands, making it harder to infect yourself or others. For example, wash your hands when you arrive at home, after using the toilet, and before preparing food.
- Avoid touching your face with your hands. This reduces the risk that you will become infected if you have the virus on your hands, and makes it less easy for you to infect others.
- Use paper tissues to blow your nose and discard them after use.
- If you do not have paper tissues, then cough and sneeze into your elbow, to keep the virus off your hands.
- Do not shake hands. Avoiding hand contact makes it harder for the virus to spread via hands.
Download the poster COVID-19 story part 2: spread and control
The government has implemented measures to prevent the virus from spreading. See the Dutch response and coronavirus measures.
Questions about how the virus spreads
Can I become infected with the coronavirus SARS-CoV-2 from food?
There is no evidence that the virus spreads through eating or preparing food. Also, coronaviruses need a living animal or human to grow and reproduce, in contrast to bacteria such as Salmonella. That means that the coronavirus SARS-CoV-2 cannot grow in food.
Can the coronavirus SARS-CoV-2 spread through glasses, crockery or cutlery?
It is possible to contract an infection involving bacteria or viruses via surfaces. Right now, there is very little risk of getting a glass that has been used by someone that is currently shedding the virus. This is because people with symptoms have to stay home. The risk of contracting the virus by drinking from a glass that has been used by someone who does not have any symptoms yet, but still turns out to have the virus, is small, but present. To minimise that risk as much as possible, it is important to ensure that the glass is properly cleaned. The same goes for crockery and cutlery. In most cases, infection occurs via droplets from sneezing / coughing and via hands. For that reason, you should follow the current hygiene guidelines and measures which apply to everyone.
Can I use a fan or air conditioning?
The page on Heat and COVID-19 offers an answer to this question and other questions about warm weather and COVID-19. Or take a look at the document addressing the role of ventilation in spreading the coronavirus SARS-CoV-2 (these documents are only available in Dutch).
Can people transmit the virus to other people before they have symptoms?
Even before you become ill, you may already be carrying the virus with you. Even before you start showing symptoms, you may already be contagious, which means you could infect others as well. The more symptoms you have, such as coughing and/or sneezing, the more you can spread the virus.
I have hay fever or allergies. Can I go outside or go to work?
In principle, yes. If you have hay fever, you have the same symptoms every year at about the same time. You will be able to recognise the normal symptoms of hay fever. The same applies to symptoms that you usually get if you are allergic to something. If there is any doubt, or if the symptoms feel different, get tested and stay home until you get the results.