Why Patients Lose Sense of Smell

Loss of smell in long COVID can last for months. (Read about "Coronaviruses") Researchers say they may have found one of the reasons for the loss of smell and other long COVID symptoms.

The researcher claim the reason some people fail to recover their sense of smell after COVID-19 is linked to an ongoing immune assault on olfactory nerve cells and an associated decline in the number of those cells. (Read about "The Immune System")

While focusing on the loss of smell, the finding also sheds light on the possible underlying causes of other long COVID-19 symptoms - including generalized fatigue, shortness of breath, and brain fog - that might be triggered by similar biological mechanisms.

In the study, the researchers analyzed olfactory epithelial samples collected from 24 biopsies, including

nine patients suffering from long-term smell loss following COVID-19.

This biopsy-based approach, using sophisticated single-cell analyses revealed widespread infiltration of T-cells engaged in an inflammatory response in the olfactory epithelium, the tissue in the nose where smell nerve cells are located. This unique inflammation process persisted despite the absence of detectable SARS-CoV-2 levels.

Additionally, the number of olfactory sensory neurons were diminished, possibly due to damage of the delicate tissue from the ongoing inflammation triggered by COVID-19.

COVID-19 can cause a range of issues, from mild symptoms to severe illness and death. The Centers for Disease Control and Prevention (CDC) say symptoms can appear days after exposure and include:

• fever
• cough
• shortness of breath or difficulty breathing
• chills
• repeated shaking with chills
• muscle pain
• headache
• sore throat
• new loss of taste or smell
• congestion or runny nose
• nausea or vomiting
• diarrhea

This list does not include all possible symptoms. CDC says it will continue to update this list as it learns more about COVID-19.

If you have any symptoms, do not go into work. Call your healthcare provider for medical advice.

Trouble breathing and /or persistent pain or pressure in the chest indicate an emergency situation and you should seek help. If you or someone around you develops new confusion or inability to arouse that too is a reason to seek care. Bluish lips or face can indicate a low oxygen level and should also be treated as an emergency.

As with other diseases caused by coronaviruses, COVID-19 is believed to spread from person to person through droplets produced when an infected person coughs or sneezes.

CDC says it is important that people take steps to protect themselves, including:

• Clean your hands often. You should wash your hands often with soap and water for at least 20 seconds. This is especially important is you have been out in public or if you have just sneezed or coughed. If you don't have access to soap and water, hand sanitizers containing at least 60 percent alcohol can be used. Rub hands with the sanitizer until they feel dry.
• Avoid touching your eyes, nose, and mouth with unwashed hands.
• Avoid close contact with people who are sick
• Put distance between yourself and other people if COVID-19 is spreading in your community. This is especially important for people who are at higher risk of getting very sick.
• Used correctly, masks can reduce the inhalation of virus-laden droplets, which can protect the person wearing the mask. Masks can also reduce the emission of virus-laden droplets, which is important so that asymptomatic people do not infect others.
• As soon as you can, CDC says you should get a COVID-19 vaccine. All of the available vaccines have been tested in clinical trials. (Read about "Clinical Studies") The studies show that the vaccines reduce your risk of contracting COVID-19, and lower the severity of the disease if you do contract it. Contact your healthcare provider or state health department to learn about your vaccine status.

If you have any symptoms, do not go into work. Call your healthcare provider for medical advice.