Mild cases of Covid-19 are more likely to lose their sense of smell, according to a study

For people with mild covid-19, the nose may know better than any other part of the body. A new study published on Wednesday suggests that almost 90% of people with mild illness they experience loss of sense of smell, a higher proportion than people with more serious illnesses. Although it is usually temporary, this odor loss can last six months and even lOnger.

The research, published in the Journal of Internal Medicine, examined the medical records of more than 2,500 covid-19 patients seeking care in one of 18 hospitals across Europe. Most were outpatients diagnosed with mild to moderate symptoms, while others were hospitalized with severe or critical covid-19.

All in all, about three-quarters of patients reported for themselves a loss of smell, medically known as anosmia. But there was a large gap in the presentation of this symptom at different levels of severity. Among patients with mild illnesses, 86% reported odor loss, compared with only 4.5% of moderate patients and 6.9% of severe patients. When fixed only in patients who had confirmed odor loss by objective testing, this gap was narrowed, but remained: 54.7% of these milder cases confirmed odor loss, compared with 36.6% of moderate to critical cases.

“Olfactory dysfunction is a prevalent disorder in covid-19 patients with a higher prevalence in patients with mild forms of the disease,” the authors wrote.

The results are consistent with previous studies demonstrating this anosmia it is a very common symptom of covid-19, although it is infrequent in the early days of the pandemic. Other research has suggested that milder cases usually have years more often. But the new study is one of the largest of its kind examining its prevalence and having data from patients who had their anosmia confirmed with evidence.

Although this study cannot tell us why the cases are milder prone to losing their sense of smell, the authors do have theories. The main explanation is that he has asthma it is ironically a sign that the body is doing a good job of defending itself from the coronavirus. In these patients, the infection never spreads beyond the upper respiratory tract, thanks to a robust and localized immune response. But that answer it can cause inflammation that damages or interferes with nearby cells that help us process the odor, at least for a short time.

There may also be some bad memories in the most severe cases. Hospital patients often treat many symptoms, while more critical patients may need intensive interventions such as a feeding tube or ventilation. Pgpatients with more severe covid-19 may not notice it his anosmia as it is happening. This could explain the higher rates of anemia in the study between moderatesa-serious cases that were actually examined.

Fortunately, for most people who experience covid-related ansmia, seems to be self-limiting. The mean time it lasted in patients was about three weeks, and about a third reported that it lasted only two weeks. But 15% of objectively examined patients lost their sense of smell for at least two months, while just under 5% still did not have it.month mark. Those with more severe anosmia at first, they were more likely to continue to experience it months later.

The authors theorize that cases of anmosemia of shorter duration they often represent nothing more than congestion and nasal swelling that is often seen with daily colds and can momentarily block our ability to sniff. But those with persistent anosmia they probably have a more complicated problem on their hands, that is, significant damage in olfactory cells, either by infection or inflammation. While most people who contract covid-19 will be able to smell it to the end, the large size of the pandemic (with 86 million cases confirmed worldwide in early January) means many people could lose their sense of smell. permanently.

The authors hope that their research will lead to future studies that look after these long-term cases to better understand the phenomenon, as well as to find out how improve that of a person possibility of recovery.