COVID-19 arrived more than a year ago. Since then, many symptoms have been related to this disease, one of them being anosmia. Although this loss of smell is very uncomfortable for those who suffer from it, it has also been discovered that it has a good side.
Italian researchers have found that recovered COVID-19 patients who lost their sense of smell during or after infection were 2.75 times more likely to have increased antibody levels after five months than the rest of the participants in the analysis. In other words, anosmia is associated with a greater and longer-lasting immune response.
"We found that there are several symptoms associated with a higher antibody rate, however, only anosmia/ageusia and chest pain were linked to the highest coefficients," the experts point out in their article, published this week on the 'medRxiv.com' portal.
The research was carried out by following and testing 4,735 healthcare professionals from 10 healthcare centers in northern Italy. During the period chosen to carry out this study, the infection curve was practically reduced to zero. For this reason, the researchers have ruled out that this increase in antibodies could be related to new contacts with the virus.
The reason why patients with anosmia have made such an important difference would be that COVID-19 could persist for a long time in the olfactory bulb, causing the immune system to keep producing antibodies and, also, causing anosmia to continue in some patients for weeks or even months.
"The increased antibody response in patients with anosmia could be linked to the persistence of the virus in the olfactory bulb, which, through local inflammation and antigen emission, maintains and boosts the antibody response," explain the Italian researchers.
Although there are further questions about the duration of immunity to COVID-19 in patients who have already had the disease, there is a scientific consensus that it lasts at least six months in symptomatic patients.
This research has also confirmed that antibody levels are gradually reduced in less than five months in the case of recovered patients who passed the disease without symptoms. However, it is still unclear to what extent the absence of detectable antibodies in blood implies vulnerability to possible reinfection.
In addition to the creation of antibodies, the infected patient also generates a B-cell response, called "memory" cells, which are responsible for the production of specific antibodies against the COVID-19 virus.
In the event of being in contact with the virus again, these cells could reactivate the immune response, even though the antibodies have already disappeared.
Smelling brings a set of sensations, emotions and pleasures that result in a state of well-being. With the arrival of COVID-19 this changed for many infected citizens, since they lost their sense of smell when infected or afterwards, and some have not yet recovered it.
"There is 90 percent of patients with anosmia who recover their sense of smell spontaneously in the first month," explained Dr. Franklin Mariño Sánchez, ENT specialist at the Ramón y Cajal Hospital, this summer.
However, the remaining 10 percent continue with this uncomfortable sensation for a longer period of time. For them, exercises to train the ability to remember, distinguish and identify odors have become essential. Exercising the brain to remember characteristic smells is essential to embark on the road to full recovery.