National Institute of Allergies and Infectious Diseases
The increased transmissibility of the new SARS-CoV-2 variant is believed to be due to a change in the spike protein, visible here in yellow under an electron microscope.
A fast-spreading variant of the coronavirus that causes COVID-19 has been found in at least 20 states, and people are wondering, How am I protecting myself now?
We saw what the new variant, known as B.1.1.7, can do as it quickly spread through South East England in December, greatly increasing the number of cases and enforcing tougher lockdown measures.
It is estimated that the new variant transmits 50% more easily than common variants, although it appears to affect people’s health in the same way. The increased transmissibility is believed to be due to a change in the spike protein of the virus that allows the virus to enter cells more easily. This and other studies on the new variant were released prior to peer review to allow for quick sharing of their findings.
In addition, there is evidence that patients infected with the new B.1.1.7 variant may have a higher viral load. That means they can expel more virus-containing particles when they breathe, talk or sneeze.
As professors studying fluid dynamics and aerosols, we investigate how airborne particles that transport viruses spread. Scientists and doctors still don’t know a lot about the coronavirus and its mutations, but there are some clear strategies people can use to protect themselves.
Air particles are still the biggest problem
The SARS-CoV-2 variants are believed to spread mainly through the air rather than on surfaces.
When someone with the coronavirus coughs, talks, sings, or even breathes in their respiratory tract, infectious droplets of respiration can be expelled into the air. These droplets are small, mainly in the 1-100 micron range. In comparison, a human hair is about 70 micrometers in diameter.
The larger droplets fall to the ground quickly, rarely traveling further than 6 feet from the source. The bigger problem for disease transmission is the smallest droplets – those less than 10 micrometers in diameter – that can linger in the air as aerosols for hours.
Since people may have more virus in their bodies and the virus is more contagious, everyone should be extra careful and take precautions. Wearing face masks and social distance are essential.
Areas and activities previously considered “safe”, such as some indoor work environments, may pose an increased risk of infection as the variant spreads.
The concentration of aerosol particles is usually highest right next to the individual emitting the particles and decreases with distance from the source. However, in indoor environments, aerosol concentrations can increase rapidly, similar to how cigarette smoke accumulates in enclosed spaces. This is especially problematic in rooms with poor ventilation.
With the new variant, aerosol concentrations that previously may not have been a risk can 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 ready-to-use face covers are not 100% effective in preventing droplet emission. Because the new variety spreads more easily and is likely to be contagious at lower concentrations, it is important to select coverings with materials that are most effective in stopping the spread of droplets.
When available, N95 and surgical masks consistently perform best. Otherwise, face covers with multiple layers of material are preferred. Ideally, the material should be tightly woven. Cotton sheets with a high thread count are an example. A good fit is also crucial as openings around the nose and mouth can reduce effectiveness by 50%.
2) Follow the guidelines for social distancing.
While current guidelines for social distances aren’t perfect – six feet is not always enough – they do provide a useful starting point. Since aerosol concentrations and infectivity are highest in the space immediately surrounding someone with the virus, increasing physical distance can help reduce risk. Remember, people are contagious before they start showing symptoms, and they often never show symptoms, so don’t count on seeing signs of illness.
3) When entering a confined space, think carefully about the environment, both the ventilation and the interaction between people.
By limiting the size of meetings, the risk of exposure is reduced. Controlling indoor environments in other ways can also be a very effective strategy to reduce 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 helpful to pay attention to the types of interactions that take place. For example, many people who yell can be at higher risk than one person speaking. In all cases, it is important to minimize the amount of time you spend indoors with others.
The CDC has warned that B.1.1.7 could become the dominant SARS-CoV-2 variant in the US in March. Other fast-spreading variants have also been found in Brazil and South Africa. Increased vigilance and adherence to health guidelines should remain a top priority.
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This story was updated on Jan. 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 has been republished from The Conversation under a Creative Commons license. Read the original article.