Prolonged illness relatively common
It has been reported that 10–33 % of people experience prolonged illness (several weeks and months) after being infected with COVID-19, and that women are twice as prone to this as men (11–13). There is still uncertainty about the extent of the long-term symptoms after the acute phase because COVID-19 is new and there is therefore no long-term data. In addition, the actual number infected with COVID-19 is assumed to be much higher than the reported figure. Various follow-up studies are underway, but most only include hospital patients. Many people with COVID-19 have self-isolated at home based on the clinical course without having been tested, since the testing capacity was inadequate up until a few months ago. These people are less likely to be included in follow-up studies. A recently published study found that certain symptom complexes were associated with an increased risk of developing long-term symptoms. If the patient had a combination of persistent cough, hoarseness, headache, shortness of breath and significant loss of appetite during the first week of COVID-19, the likelihood of subsequently experiencing long-term symptoms increased two- to threefold (14).
It has been reported that 10–33 % of people experience prolonged illness after being infected with COVID-19, and that women are twice as prone to this as men
Other viral infections have been shown to cause long-term sequelae (postviral syndromes), however little is known about the long-term effects of COVID-19 and few studies have been conducted. The extent to which other postviral syndromes can be extrapolated to COVID-19 patients is also uncertain (15). There are an increasing number of reports of long-term courses of COVID-19. Some of these descriptions are by doctors who have had the disease themselves and have reported long-term symptoms after the acute phase (16–18). Others cover larger populations (11), (19–20).
In a survey of both hospitalised and non-hospitalised COVID-19 patients with confirmed SARS-CoV-2, respondents were contacted 14–21 days after testing. Approximately one third (36 %) of the non-hospitalised patients indicated that they had not returned to their normal condition. The most common symptoms were pleuritic pain (74 %), fatigue (70 %), headache (62 %), cough (62 %), body aches (58 %), fever (55 %), chills (52 %) and loss of sense of taste and smell (52 %) (11). In another recently published article from Italy, researchers describe persistent symptoms in a population of 143 patients who were followed up for an average of 60 days after hospitalisation for COVID-19 (19). Only 18 (12.6 %) of these patients had been treated in an intensive care unit, so most had a non-serious acute course. A total of 21 patients (15 %) received non-invasive ventilation and 7 patients (5 %) received invasive ventilation. Of the 143 patients, only 18 (12.6 %) were completely free of any COVID-19-related symptoms. A significant proportion reported continued fatigue (53 %), shortness of breath (43 %), joint pain (27 %) and chest pain (22 %). Forty-four per cent of the patients also reported a reduced quality of life.