New York, April 23 : Covid-19 survivors -- including those not sick enough to be hospitalised -- have an increased risk of death in the six months following diagnosis with the virus, a large study claimed. The study, led by researchers at Washington University's School of Medicine in St. Louis,A involved more than 87,000 Covid-19 patients and nearly five million control patients. The team found that after surviving the initial infection (beyond the first 30 days of illness), Covid-19 survivors had an almost 60 per cent increased risk of death over the following six months. At the six-month mark, excess deaths among all Covid-19 survivors were estimated at eight people per 1,000 patients. Among patients who were ill enough to be hospitalised with Covid-19 and who survived beyond the first 30 days of illness, there were 29 excess deaths per 1,000 patients over the following six months. "Our study demonstrates that up to six months after diagnosis, the risk of death following even a mild case of Covid-19 is not trivial and increases with disease severity," said Ziyad Al-Aly, Assistant Professor of medicine at the varsity. "These later deaths due to long-term complications of the infection are not necessarily recorded as deaths due to Covid-19. As far as total pandemic death toll, these numbers suggest that the deaths we're counting due to the immediate viral infection are only the tip of the iceberg," Al-Aly said. The findings, published online in the journal Nature, reveals the massive burden this disease is likely to place on the world's population in the coming years. Covid-19 survivors had a 50 per cent increased risk of death compared with flu survivors, with about 29 excess deaths per 1,000 patients at six months. Survivors of Covid-19 also had a substantially higher risk of long-term medical problems. Moreover, despite being initially a respiratory virus, long Covid-19 can affect nearly every organ system in the body, including: respiratory system, nervous system, mental health, metabolism, cardiovascular system, gastrointestinal system, kidney, coagulation regulation, skin, musculoskeletal system and general health, the researchers noted. In addition, the health risks from surviving Covid-19 increased with the severity of disease, with hospitalised patients who required intensive care being at highest risk of long Covid-19 complications and death. Al-Aly said that "it is not an exaggeration to say that long Covid-19 -- the long-term health consequences of Covid-19" is the world's next big health crisis. "...The lingering effects of this disease will reverberate for many years and even decades. Physicians must be vigilant in evaluating people who have had Covid-19. These patients will need integrated, multidisciplinary care," Al-Aly said. /IANS