A new study explains why many people with Covid-19 lose their ability to smell and taste. The virus responsible for Covid-19, known as SARS-CoV-2, can infect special nerve cells called sensory neurons. These neurons are responsible for our sense of smell and taste.
How It Happens
When Covid-19 first spread in 2020, it caused common symptoms related to our nervous system, which helps our brain communicate with our body. Smell and taste depend on sensory neurons found in this system. Initially, experts thought the virus couldn’t infect these neurons, but a team from the Whitehead Institute for Biomedical Research in the US discovered that it can.
Why It Matters
Understanding how the virus affects these neurons helps us figure out why people lose their sense of smell and taste. This knowledge is crucial for developing treatments. Rudolf Jaenisch, a researcher at the Whitehead Institute, says, “Knowing that the virus can infect and change the function of these cells gives us a clue about what’s causing the problem.”
The Study
In their study, the researchers created sensory neurons in a lab from special cells. They then tested whether these neurons had a gene called ACE2, which the virus needs to enter our cells. They found that these sensory neurons did have ACE2, just like other cells that the virus can infect.
The researchers exposed these neurons to three different strains of the virus, including the original strain and the Delta and Omicron variants. They discovered that all three strains of the virus could infect some of the sensory neurons. Omicron, however, infected the fewest cells and was slower at doing so. This might explain why Omicron causes fewer people to lose their sense of smell and taste, but more research is needed to confirm this.