Health limits due to pandemic significantly curtailed attendance to annual event, which usually attracts millions.
More than three-quarters of people hospitalised with COVID-19 still suffered from at least one symptom after six months, according to a new study.
The research, which was published on Saturday in the Lancet medical journal, involved hundreds of patients in the Chinese city of Wuhan, where the new coronavirus was first detected.
It found that fatigue or muscle weakness were the most common symptoms, while people also reported sleeping difficulties.
Scientists said the study – among the few to trace the long-term symptoms of COVID-19 – shows the need for further investigation into lingering coronavirus effects.
“Because COVID-19 is such a new disease, we are only beginning to understand some of its long-term effects on patients’ health,” said lead author Bin Cao, of the National Center for Respiratory Medicine.
The professor said the research highlighted the need for continuing care for patients after they have been discharged from hospital, particularly those who have had severe infections.
The new study included 1,733 COVID-19 patients discharged from Jinyintan Hospital in Wuhan between January and May last year.
Patients, who had an average age of 57, were visited between June and September and answered questions on their symptoms and health-related quality of life.
Researchers also conducted physical examinations and lab tests.
The study found that 76 percent of patients who participated in the follow-up (1,265 of 1,655) said they still had symptoms.
Fatigue or muscle weakness was reported by 63 percent, while 26 percent had sleep problems.
The study also looked at 94 patients whose blood antibody levels were recorded at the height of the infection as part of another trial.
When these patients were retested after six months, their levels of neutralising antibodies were 52.5 percent lower.
The authors said this raises concerns about the possibility of COVID-19 reinfection, although they said larger samples would be needed to clarify how immunity to the virus changes over time.
The World Health Organization has said the virus poses a risk for some people of serious continuing effects – even among young, otherwise healthy people who were not hospitalised. To date, there have been more than 89 million confirmed coronavirus cases, including some 1.9 million related deaths and 49.5 million recovered.
“Patients have to be seen over a period of six months or longer due to complications of contracting the virus. That means we’re going to have even less capacity, less healthcare workforce available for treating these individuals,” Oksana Pyzik, global health adviser and lecturer at UCL, told Al Jazeera.
“That will have knock-on consequences for caring for all sorts of chronic conditions,” such as cancer, Pyzik said.
In a comment article, which was also published in the Lancet, Monica Cortinovis, Norberto Perico, and Giuseppe Remuzzi, from Italy’s Istituto di Ricerche Farmacologiche Mario Negri IRCCS, said there was uncertainty over the long-term health consequences of the pandemic.
“Unfortunately, there are few reports on the clinical picture of the aftermath of COVID-19,” they said, adding the latest study was, therefore, “relevant and timely”.
They said longer-term multidisciplinary research being conducted in the United States and the United Kingdom would help improve understanding and help develop therapies to “mitigate the long-term consequences of COVID-19 on multiple organs and tissues”.