Long Covid symptoms last up to a year in mild cases, study says

New research on Covid long noted that, in most patients in whom the symptoms of the infection were mild, the sequelae caused by the disease disappear within a year of diagnosis. The conclusion may be an indication that, although dangerous, the long Covid must be overcome by most of those affected.

The study, published this Wednesday (11) in the scientific journal BMJ, considered data from almost 600,000 patients in Israel with positive and negative tests for Covid between March 2020 and October 2021. The information was contained in an important health database Israeli.

One of the objectives was to observe how long people who had mild symptoms of Covid maintained the consequences. For this, the research compared the incidence of about 70 symptoms associated with long-term Covid in people who were infected by the virus and had mild illness. This group was compared to other people who underwent tests and had negative results.

The presence of sequelae in the participants was divided into two periods: the initial phase, which comprised 30 to 180 days from the infection; and the long stage, from 180 to 360 days. Based on the comparison of the two samples, it was possible to observe how much Covid-19 was associated with the onset of sequelae and for how long they persisted.

For some symptoms, such as hair loss and respiratory complications, infection with Sars-CoV-2 represented a potential risk, compared to people who tested negative for the disease. But the greatest chance of developing these sequelae was concentrated in the initial phase after infection.

In the case of other sequelae, however, Covid played an important role up to a year after the positive test. Loss of smell and taste, cognitive impairment, weakness and palpitation are part of this list.

Even if these sequelae persisted for a longer period after the acute phase of Covid-19, the research concluded that, to a large extent, they resolved up to a year after infection with the virus. According to the researchers wrote in the article, the conclusion is an indication that “although the long Covid is a feared and discussed phenomenon since the beginning of the pandemic”, the sequels should not continue for a very long period in people with mild cases of the disease.

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The article also reported some specific research findings. The scientists checked, for example, whether there was any connection between the onset of sequelae and the patient’s age.

In children, the incidence of sequelae was lower than that observed in adults and the elderly. On the other hand, when there was any, children usually only recovered from the sequel after the seventh month of infection.

At the other pole, seniors over 60 were more likely to develop long-term Covid symptoms – the main thing was hair loss. But unlike children, full recovery occurred within the first six months after diagnosis.

The sex of the participants and the variants of the coronavirus, on the other hand, had no connection with the appearance of sequels, according to the study. Furthermore, the research noted that vaccination had a positive effect to reduce the risks of feeling short of breath. In the case of other sequelae, vaccinated individuals were not less likely to develop them compared to those who had not yet been immunized.

A Brazilian study published last week in a pre-print model (that is, without review by other scientists), however, brought different results.

In the Brazilian investigation, women had a higher risk for long-term Covid, compared to men. In addition, infections caused in the waves of the delta and omicron variants were associated with a lower number of persistent symptoms. Lastly, the national survey saw a large positive effect of the fourth dose of the long Covid vaccine.