Coronavirus infection may alter the senses of smell and taste, During the first months of the pandemic causing the new disease, it was unknown whether this change could also be a symptom of the virus’s presence in the human body. But scientific research advanced and How frequent is the smell disturbance, which in some patients persists even after examination of the acute stage of the disease. This is a wake-up call for them after the pandemic.
The pandemic sparked “increasing public health concern” about people losing their sense of smell, according to research published in the journal JAMA Otolaryngology-Head and Neck Surgery, TookResearchers estimate that 700,000 to 1.6 million people in the United States who were infected with the coronavirus have lost or had a change in their sense of smell that lasted more than 6 months. According to the authors, who are from Washington University School of Medicine in St. Louis, this figure may be an underestimate.
The new study suggested that most people regain their sense of smell over time, but some may never regain it. The authors consider this worrying, because by comparison, Before the pandemic, only 13.3 million adults age 40 and older had what scientists call olfactory disease (OD) or chronic olfactory dysfunction (COD). “These data suggest an emerging public health concern of OD and an urgent need for research that focuses on the treatment of olfactory dysfunction due to COVID-19,” said Amish Khan authors Dorina Kalogjeri and Jay Piccirillo. “
Earlier, Another study found that 72% of people with COVID-19 regained their sense of smell within a month, but for some the process is much slower. According to Dr. John Hayes, director of the Center for Sensory Assessment at the University of Pennsylvania College of Agricultural Sciences, ,Chronic disease problems will last for decadesHess was not involved in the new study. He believed that the problem of smell could affect several million more people.
Not being able to smell includes health risks, Although long-term loss of smell may seem minor compared to other symptoms of coronavirus infection, not being able to smell can be dangerous. A study in 2014 found that Those who lost their sense of smell had more than twice the risk of experiencing dangers such as eating spoiled food., Loss of the sense of smell has also been linked to depression in previous studies.
Humanity’s attention to the sense of smell has always been short. Furthermore, the medical and scientific community has not devoted as many hours of research with the other senses as to whether smell disorders have minor effects or are due to lack of treatment. But the coronavirus pandemic changed everything.
Since one of the most frequent symptoms is a lack of smell in patients, there has been an increase in studies on this sense. In addition, studies have been reinterpreted that have provided evidence of how changes in smell – beyond COVID-19 – affect quality of life and worsen health as they lead to anxiety, eating and weight gain. problems and can lead to depression.
With the pandemic it was clear that Smell is not a secondary sense. It is considered an important indicator of our health. Last year, two major research initiatives were launched, the Global Consortium for Chemosensory Research and SmellTracker. They were set up to study in detail what happens to the olfactory sense with COVID-19 infection. From data collected over months on thousands of people around the world, they have found that olfactory neurons are targets of the coronavirus, regardless of where they circulate in each country.
According to one of the researchers, Sarah Spinelli from the Sensory Laboratory of the University of Florence, “The increase in reports of changes in smell and taste is considered a marker of a very early increase in cases and direct hospitalization, thus as a Index of the effectiveness of distancing measures in: new reported cases of change are reduced by exactly five days after a confinement”.
At the start of the pandemic, the virus was thought to attack olfactory neurons via Ace-2 receptors. They are the same ones that entered other cells. Even then, Sandeep Dutta, a neurobiologist at Harvard University, found that these receptors are not expressed by olfactory neurons., but by other cells that surround them and by stem cells found in the olfactory bulb, stem cells are needed to repair recurrent damage, Olfactory sensory neurons are exposed by being in direct contact with the outside.
From the study, Dr. Dutta explained that the exact target of the virus may explain why patients who lose their sense of smell have very different treatment trajectories. In some, the change is only temporary because only the so-called support cells, which act as physical and metabolic support for the neurons, have been damaged.
Instead, In other patients with COVID-19, The damage is different: neurons die and can repair from stem cells in months, so olfactory abnormalities persist for a long time, In others, the virus attack may have affected helper cells and stem cells. This inhibits the growth of new neurons and, therefore, the recovery of olfactory function.
The work led by Dutta will also explain parosmia and phantosmia, i.e. conditions in which the patient feels that the smell is not true – alcohol may smell like gasoline, shampoo rancid – or they do not exist. During the repair phase the neural connections altered by the virus are poorly “reconnected” and this leads to irregular olfactory signaling pathways.
“according to research, Odor recovery is more or less slow and complete according to individual characteristics; As age and disease severity increase, it becomes more difficult, But even young people who have few symptoms can take months to smell again.”Spinelli added.
Along with research on smell, the indications for better treatments have also increased. “The kit is likely to help patients regain their sense of smell, through a process of so-called re-acquaintance and to gradually become accustomed to different odors: studies are still ongoing and today To date it is not known which protocol guarantees the best results and the time required for full recovery,” Spinelli said.
Previously, other researchers have found the results to consider odor changes associated with various diseases. Changes in smell can be an early sign of diseases affecting the central nervous system. If brain damage involves the olfactory regions, the ability to smell good is reduced. 38% of patients with multiple sclerosis and about half of those diagnosed with dementia had symptoms of loss of smell approximately five years before the onset of neurological symptoms. In the case of Parkinson’s disease, olfactory abnormalities are also estimated to occur in between 45% and 96% of cases. Considering odor as an indicator, the Predict-PD project has been launched in the United Kingdom. A smell test is done to identify in advance who may be affected by the disease.
According to the Mayo Clinic in the United States, If a person notices a decrease in taste and smell, they should see a doctor. “Although age-related taste and smell decline cannot be reversed, some of its causes can be treated. For example, doctors can change medications if they are contributing to the problem. This multiple nosebleeds And can also treat sinus conditions and dental problems,” he advises.
If you use tobacco, quitting can help restore your ability to smell. Through medical consultation, the health professional can refer to an allergist, otolaryngologist, neurologist, or other specialist, depending on each patient’s condition.