More than half of the 236 million people who have recovered from COVID-19 worldwide since December 2019 will experience post-COVID symptoms more commonly known as long COVID up to six months after recovering, according to a large study.

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The lingering COVID symptoms majorly include tiredness, difficulty in breathing, chest pain, sore joints and loss of taste or smell. A research team from Pennsylvania State University in the US examined 57 global studies involving 250,351 unvaccinated patients who recovered from COVID -19 from December 2019 through March 2021.

The findings showed that adults, as well as children, can experience several adverse health issues for six months or longer after recovering from COVID -19. Generally, these complications affected a patient's general well-being, mobility or organ systems, while overall, one in two survivors experienced long-term COVID manifestations.

More than half of all patients reported weight loss, fatigue, fever or pain, roughly one in five survivors experienced a decrease in mobility. Nearly one in four survivors experienced difficulty concentrating, and one in three patients were diagnosed with generalised anxiety disorders. Six in ten survivors had chest imaging abnormality and more than a quarter of patients had difficulty in breathing.

Chest pain and palpitations were also among the commonly reported conditions and nearly one in five patients experienced hair loss or rashes. Digestive issues such as stomach pain, lack of appetite, diarrhoea and vomiting were also among the commonly reported conditions, the study showed.

"One's battle with COVID doesn't end with recovery from the acute infection. Vaccination is our best ally to prevent getting sick from COVID-19 and to reduce the chance of long-COVID even in the presence of a breakthrough infection," said co-lead investigator Dr Paddy Ssentongo, assistant professor at the Penn State Center for Neural Engineering.

While the mechanisms behind these lingering symptoms in survivors are not fully understood, the researchers believe that an immune-system overdrive triggered by the virus, lingering infection, reinfection or increased production of autoantibodies (antibodies directed at their own tissues), maybe the reason.

According to the researchers, early intervention will be critical for improving the quality of life for many COVID -19 survivors as in the years ahead, health care providers will likely see an influx of patients with psychiatric and cognitive problems, such as depression, anxiety or post-traumatic stress disorder, who were otherwise healthy before their COVID -19 infection.