As of October 10, 2021, over 239 million people are known to have been infected with SARS-CoV-2, the virus that causes COVID-19. Researchers have now estimated that about half of those people have experienced symptoms known as long COVID or post-acute COVID syndrome, for up to six months after the onset of infection. The findings have been reported in JAMA Open, and the study authors are warning officials and clinicians that preparations should be made to assist the many COVID-19 patients who may continue to suffer these widely varied complications.
The initial phase of COVID-19 can include loss of smell, chest or joint pain, fatigue, difficulty breathing, or fever. These may linger for months, and other symptoms can set in.
This research assessed 57 previous studies to learn more about how unvaccinated COVID-19 patients were doing in the six months or more after they recovered; this effort included over 250,000 people diagnosed between December 2019 and March 2021. Just over half of these patients were male, their median age was 54, 79 percent were residents of high-income countries, and 79 percent had been hospitalized.
The health of the individuals was assessed at three points: one month, two to five months, and over six months to cover short-, intermediate-, and long-term periods, respectively. One in two patients were found to have health problems that were chronic from one through sixth months after their initial bout with COVID-19. Over half of the patients experienced fever, fatigue, or weight loss. One in five were less mobile. One in three had generalized anxiety, and about one in four had concentration difficulties. Over one in four had breathing difficulties, and almost one in five had rashes or hair loss. Diarrhea, vomiting, chest pains or heart palpitations were common.
"The burden of poor health in COVID-19 survivors is overwhelming," said co-lead investigator Dr. Paddy Ssentongo, assistant professor at the Penn State Center for Neural Engineering. "Among these are the mental health disorders. 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," Ssentongo noted.
Researchers are still learning more about what causes long COVID. Studies have suggested that it may involve immune system overactivity, autoantibodies that attack the body, or reinfections. The virus may also hang around in the immune system. There could also be different reasons for these lingering symptoms in different patients, or comorbidities that contribute to the complications.
"Our study was not designed to confirm COVID-19 as the sole cause of these symptoms. It is plausible that symptoms reported by patients in some of the studies examined were due to some other causes," Ssentongo noted.
The study authors added that the influx of long COVID patients could put a greater burden on the health care system, especially in places where it may have been inadequate before the pandemic. Since long COVID can involve a huge variety of symptoms that impact different systems, the researchers suggested that it may be important to set up clinics where long COVID patients can be treated for all of these problems at the same place rather than having to visit different specialists.
