Dr. Sebastian Blockus, Applied Scientist at BODE SCIENCE CENTER – HARTMANN’s scientific center of excellence – explains the science behind virus transmission and the steps we can take to protect ourselves from COVID-19.
If we think about some of the most common viral diseases, it’s clear that there are a few different ways viruses can spread. We can get norovirus from contaminated food and water, HIV is a bloodborne pathogen and it’s possible to pick up the common cold just from sitting too close to an infected co-worker. These viruses all spread through different transmission routes – the main ones being air, water, blood/tissue and contact – and it’s possible for some viruses to be transmitted through more than one route. Identifying routes of transmission helps determine the exact precautions and measures we need to take to prevent infection.
SARS-CoV-2, the virus behind COVID-19, can be spread through two critical routes of transmission – air (via droplets) and contact transmission. In the case of droplet transmission, the virus is spread through very fine droplets e.g. after coughing, sneezing or even speaking. Although these particles fall to the ground relatively quickly and do not remain in the air, they could be transported short distances (< 2 m) and reach another person’s mouth, nose or eyes.
The second route of infection for SARS-CoV-2 is through contact (or smear) infection – either direct (by touching an infected person) or indirect (by touching contaminated objects).
There are a few key measures you can take to stop droplet and contact transmission – many of which you’re probably already familiar with. When looking at droplet transmission, it’s important to keep a minimum distance of 1.5-2 m from other people. Using your elbow or a tissue to cover your mouth and nose when coughing or sneezing can also help to prevent droplet transmission.
Hand hygiene is crucial to stopping the spread of infection. Be sure to clean your hands after entering or leaving the workplace; after coughing, sneezing or blowing your nose; before eating, drinking or taking medication; after using the toilet; after contact with frequently touched surfaces; and after using public transport. You should also avoid touching your eyes, nose and mouth, as this can allow the virus to enter your body. If you use a disinfectant, it’s important to apply enough solution to the palm of your hand to cover both hands completely. Next, rub the disinfectant thoroughly into your hands, paying careful attention to your fingertips and thumbs, including the nail folds. Take care to choose a disinfectant with the necessary spectrum of activity. SARS-CoV-2 is an enveloped virus and can therefore be inactivated using a disinfectant, which is at least virucidal against enveloped viruses.
See our guide to effective hand hygiene for more tips. Additionally, regular cleaning of frequently touched surfaces and objects (e.g. doorknobs, desks, handles and digital devices) is also key to stopping indirect transmission and subsequent spread of infection.
Given that SARS-CoV-2 emerged only recently, scientific data is increasing, but still limited. Due to its similarities to other coronaviruses, it is very likely that SARS-CoV-2 can persist on inanimate surfaces. Recent studies show that SARS-CoV-2 can survive for up to 48-72 hours on plastic and stainless steel, less than 24 hours on cardboard and less than 4 hours on copper. However, environmental and mechanical influences (e.g. humidity, temperature and transportation) have a huge impact on the infectivity and persistence of viruses on surfaces.
