Around half of study participants had symptoms of long Covid at two years and reported lower quality of life than those without long Covid.
A study conducted in China between January 2020-2022 found that more than two years are needed for a full recovery from Covid-19, as more than half of the people hospitalised with coronavirus infections in the study had at least one symptom more than two years after their first infection.
The study, conducted on 1,192 participants, was published in The Lancet Respiratory Medicine Journal. It tracked hospitalised patients at intervals of six months, 12 months, and two years, and is the longest of its kind so far in the world.
While physical and mental health generally improved over time, the study suggests that Covid-19 patients still tend to have poorer health and quality of life than the general population.
This is especially the case for participants with long Covid, who typically still have at least one symptom including fatigue, shortness of breath, and sleep difficulties two years after initially falling ill, the researchers said.
The study participants were assessed on tests that involved a six-minute walking test, laboratory tests, and questionnaires on symptoms, mental health, health-related quality of life, if they had returned to work, and health-care use after discharge, according to the researchers.
Testing negative after being infected with coronavirus is only the first step towards recovery. Usually, symptoms such as fatigue, cough, shortness of breath, etc, continue for a few week.
However, if you have these symptoms, or any other Covid-19 symptoms, even after 12 months of testing negative and these symptoms cannot be attribute to any other diagnosis, then you likely have long Covid.
Long Covid, and these long-term symptoms, may be physical such as shortness of breath, fatigue, and cough, and mental as well. The mental effects are called "brain fog", which is an umbrella term for a range of cognitive issues such as forgetfulness, lack of clarity of mind, poor concentration, inability to focus, and a persisting feeling of confusion.
The study's lead author, Professor Bin Cao, of the China-Japan Friendship Hospital, said, "Our findings indicate that for a certain proportion of hospitalised Covid-19 survivors, while they may have cleared the initial infection, more than two years is needed to recover fully from Covid-19.
"Ongoing follow-up of Covid-19 survivors, particularly those with symptoms of long Covid, is essential to understand the longer course of the illness, as is further exploration of the benefits of rehabilitation programmes for recovery."
The researchers noted that there is a clear need to provide continued support to a significant proportion of people who have had Covid-19 and to understand how vaccines, emerging treatments, and variants affect long-term health outcomes.
Six months after initially falling ill, 68 per cent of participants reported at least one long Covid symptom, according to the researchers.
By two years after infection, reports of symptoms had fallen to 55 per cent.
Fatigue or muscle weakness were the symptoms most often reported and fell from 52 per cent at six months to 30 per cent at two years.
Regardless of the severity of their initial illness, 89 per cent of participants had returned to their original work at two years.
The researchers noted that two years after initially falling ill, patients with Covid-19 are generally in poorer health than the general population, with 31 per cent reporting fatigue or muscle weakness and 31 per cent reporting sleep difficulties.
Covid-19 patients were also more likely to report a number of other symptoms including joint pain, palpitations, dizziness, and headaches, as per the researchers.
Around half of study participants had symptoms of long Covid at two years, and reported lower quality of life than those without long Covid. This is in line with an earlier study at University of Michigan that found at least 40 per cent of people infected with coronavirus develop long Covid.
In mental health questionnaires, 35 per cent reported pain or discomfort and 19 per cent reported anxiety or depression.
Long COVID participants also more often reported problems with their mobility or activity than those without the disorder.
The researchers said that it is hard to determine whether observed abnormalities are specific to Covid-19 without a control group of hospital survivors unrelated to Covid-19 infection.
The slightly increased proportion of participants included in the analysis who received oxygen leads to the possibility that those who did not participate in the study had fewer symptoms than those who did, according to the researchers.
This may result in an overestimate of the prevalence of long COVID symptoms, they added.
(With PTI inputs)