National Institute of Allergies and Infectious Diseases
The increased transmissibility of the new SARS-CoV-2 variant is thought to be due to a change in the spike protein, visible here in yellow under the electron microscope.
A rapidly spreading variant of the coronavirus that causes COVID-19 has been found in at least 20 states, and people are wondering: How do I protect myself now?
We have seen what the new variant, known as B.1.1.7, can do, as it is spreading rapidly through the south-east of England in December, increasing the number of cases and triggering stricter blocking measures.
It was estimated that the new variant is 50% easier to transmit than the usual variants, although it seems to affect people’s health in the same way. Increased transmissibility is thought to occur from a change in the virus’s peak protein, which can allow the virus to enter cells more easily. These and other studies on the new variant were launched before the peer review to quickly share their findings.
In addition, there is some evidence that patients infected with the new variant B.1.1.7 may have a higher viral load. This means that they can expel more particles that contain viruses when they breathe, talk or sneeze.
As teachers who study the dynamics of fluids and aerosols, we investigate how airborne particles that carry viruses spread. There are still many things that scientists and doctors do not know about coronavirus and its mutations, but there are some clear strategies that people can use to protect themselves.
Airborne particles are still the biggest problem
SARS-CoV-2 variants are thought to spread mainly through the air, rather than on surfaces.
When someone with a coronavirus in their airways coughs, speaks, sings or even breathes, infectious respiratory drops can be expelled into the air. These drops are small, predominantly in the range of 1-100 micrometers. For comparison, human hair is about 70 micrometers in diameter.
Larger droplets fall to the ground quickly, rarely traveling beyond 6 feet from the source. The biggest problem for the transmission of the disease are the smallest drops – those with a diameter of less than 10 micrometers – that can remain suspended in the air as aerosols for hours.
If people probably have more viruses in their body and the virus is more infectious, everyone should take extra care and precautions. Wearing face masks and social distancing are essential.
Spaces and activities that were previously considered “safe”, such as some indoor work environments, may be at increased risk of infection as the spread spreads.
The concentration of aerosol particles is usually highest right next to the individual emitting the particles and decreasing with distance from the source. However, in indoor environments, aerosol concentration levels can accumulate rapidly, similar to how cigarette smoke accumulates indoors. This is especially problematic in areas with poor ventilation.
With the new variant, aerosol concentration levels that were not previously a risk could now lead to infection.
What can you do to stay safe?
1) Pay attention to the type of face mask you are using and how it fits.
Most front shelf covers are not 100% effective in preventing drip emissions. Since the new variant spreads more easily and is probably infectious at lower concentrations, it is important to select the coatings with materials that are most effective in stopping the spread of the drops.
When available, N95 and surgical masks have the best results. Otherwise, face coatings that use multiple layers of material are preferable. Ideally, the material should be a tight fabric. Cotton sheets with a large number of threads are an example. Correct fit is also crucial, as gaps around the nose and mouth can reduce effectiveness by 50%.
2) Follow the guidelines on social distancing.
Although current social distance guides are not perfect – 6 feet is not always enough – they provide a useful starting point. Because levels of aerosol concentrations and infectivity are highest in the space immediately surrounding anyone with the virus, increasing physical distance can help reduce risk. Remember that people are infectious before they start showing symptoms and many never show symptoms, so don’t rely on seeing signs of illness.
3) Think carefully about the environment when you enter a closed area, both the ventilation and the way people interact.
Limiting the size of assemblies helps reduce the potential for exposure. Controlling indoor environments in other ways can also be an extremely effective strategy for reducing risk. This includes increasing ventilation rates to bring in fresh air and filtering existing air to dilute aerosol concentrations.
On a personal level, it is useful to pay attention to the types of interactions that take place. For example, many shouting individuals may create a higher risk than a talking individual. In all cases, it is important to minimize the time spent indoors with others.
The CDC has warned that B.1.1.7 could become the dominant SARS-CoV-2 variant in the United States by March. Other fast-growing variants have been found in Brazil and South Africa. Increased vigilance and adherence to health guidelines should continue to be a top priority.
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This story was updated on January 18, with the latest CDC count and map showing B.1.1.7 cases now found in 20 states.
By Suresh Dhaniyala, Bayard D. Clarkson Distinguished Professor of Mechanical and Aeronautical Engineering, Clarkson University and Byron Erath, Associate Professor of Mechanical Engineering, Clarkson University
This article is republished from Conversation under a Creative Commons license. Read the original article.