#masthead-section-label, #masthead-bar-one { display: none }The Coronavirus OutbreakliveLatest UpdatesMaps and CasesRisk Near YouVaccine RolloutNew Variants TrackerAdvertisementContinue reading the main storySupported byContinue reading the main storyMany ‘Long Covid’ Patients Had No Symptoms From Their Initial InfectionAn analysis of electronic medical records in California found that 32 percent started with asymptomatic infections but reported troubling aftereffects weeks and months later.The study of 1,407 people who tested positive for coronavirus found more than 30 symptoms, including anxiety, low back pain, fatigue, insomnia, gastrointestinal problems and rapid heart rate.Credit…Pete Kiehart for The New York TimesMarch 8, 2021, 6:52 p.m. ETMany people who experience long-term symptoms from the coronavirus did not feel sick at all when they were initially infected, according to a new study that adds compelling information to the increasingly important issue of the lasting health impact of Covid-19.The study, one of the first to focus exclusively on people who never needed to be hospitalized when they were infected, analyzed electronic medical records of 1,407 people in California who tested positive for the coronavirus. More than 60 days after their infection, 27 percent, or 382 people, were struggling with post-Covid symptoms like shortness of breath, chest pain, cough or abdominal pain.Nearly a third of the patients with such long-term problems had not had any symptoms from their initial coronavirus infection through the 10 days after they tested positive, the researchers found.Understanding long-term Covid symptoms is an increasingly pressing priority for doctors and researchers as more and more people report debilitating or painful aftereffects that hamper their ability to work or function the way they did before. Last month, the director of the National Institutes of Health, Dr. Francis S. Collins, announced a major initiative “to identify the causes and ultimately the means of prevention and treatment of individuals who have been sickened by Covid-19, but don’t recover fully over a period of a few weeks.”David Putrino, director of rehabilitation innovation at Mount Sinai Health System in New York City, who was not involved in the new research, said that he and his colleagues at Mount Sinai’s center for post-Covid care are seeing a similar pattern.“Many people who had asymptomatic Covid can also go on to develop post-acute Covid syndrome,” said Dr. Putrino, who is a co-author of a smaller study on the topic published last year. “It doesn’t always match up with severity of acute symptoms, so you can have no symptoms but still have a very aggressive immune response.”The new study is published on the preprint site MedRxiv and has not finished undergoing peer review. Its strengths include that it is larger than many studies on long-term symptoms published so far and that the researchers used electronic records from the University of California system, allowing them to obtain health and demographic information of patients from throughout the state. The researchers also excluded from the study symptoms that patients had reported in the year before their infection, a step intended to ensure a focus on post-Covid symptoms.Among their findings: Long-term problems affect every age group, including children. “Of the 34 children in the study, 11 were long-haulers,” said one of the authors, Melissa Pinto, an associate professor of nursing at the University of California Irvine.The study found more than 30 symptoms, including anxiety, low back pain, fatigue, insomnia, gastrointestinal problems and rapid heart rate. The researchers identified five clusters of symptoms that seemed most likely to occur together, like chest pain and cough or abdominal pain and headache.Most previous studies of long-term symptoms have tended to involve people who were sick enough from their initial infection to be hospitalized. One of the largest found that more than three-quarters of about 1,700 hospitalized patients in Wuhan, China, had at least one symptom six months later.The Coronavirus Outbreak