Worldwide, at least 65 million people have long COVID, and that is likely an underestimate, finds a review article published late last week in Nature Reviews Microbiology.
Investigators from the Patient-Led Research Collaborative and Scripps Research Translational Institute reviewed the current literature on long-COVID in nonhospitalized adults.
The researchers said that the number of affected COVID-19 survivors was based on the estimated global rate of 10% of infected people and the more than 651 million documented cases. They cited the lack of polymerase chain reaction (PCR) test availability at the beginning of the pandemic and the high false-negative rate of rapid antigen tests as reasons for suspecting an undercount.
"Similarly, there is a broad misconception that everyone makes and retains SARS-CoV-2 antibodies, and many clinicians and researchers are unaware of the limited utility of antibody tests to determine prior infection," they wrote. "Between 22% and 36% of people infected with SARS-CoV-2 do not seroconvert, and many others lose their antibodies over the first few months."
There is a broad misconception that everyone makes and retains SARS-CoV-2 antibodies.
This misinformation, as well as the underrecognition of the nonrespiratory manifestations of long COVID, have skewed both the electronic health record (EHR) data and the research output, the authors said.
EHR data, they continued, are also more comprehensive for hospitalized patients, "leading to a bias toward the more traditional severe respiratory presentation and less focus on non-hospitalized patients," who tend to have neurologic or immune-related presentations.
The researchers said that current diagnostic and treatment options for long COVID are lacking and that clinical trials are needed to pinpoint the condition's mechanisms. "Additionally, to strengthen long COVID research, future studies must account for biases and SARS-CoV-2 testing issues, build on viral-onset research, be inclusive of marginalized populations and meaningfully engage patients throughout the research process," they wrote.
The team also called for training of the healthcare and research workforce on long COVID, a public education campaign, and policies and funding to support research and patient care.