History of severe pain episodes and coexisting organ conditions increase the risk of severe Covid-19 illness, including hospitalisation, in individuals living with sickle cell disease (SCD) -- common inherited red blood cell disorder, finds a study.SCD can cause severe pain, joint and organ damage, and stroke; these conditions predispose individuals with SCD to worse outcomes with infections, including infection with Covid-19.The study, published in the journal Blood Advances, found that pain was the most common presenting symptom during Covid-19 illness in both children and adults living with SCD, and that many patients only had pain as their presenting Covid-19 symptom."This means individuals with sickle cell disease who come to the hospital presenting with pain should also be tested for Covid-19," said Lana Mucalo, from the Medical College of Wisconsin.Children living with SCD who had previously suffered more than two pain events requiring acute care were 2.2 times more likely to be hospitalised for Covid-19 and more than three times likely to suffer severe Covid illness.Those with more than two prior acute care visits for pain were 1.8 times more likely to be hospitalised with Covid and 1.9 times more likely to suffer severe Covid-19 illness.SCD-related heart, lung, and kidney conditions were associated with higher risk of severe illness in children, while SCD-related heart and lung conditions were also associated with higher risk of hospitalisation. However, these conditions did not have the same effect in adults."This study tells us that all individuals with sickle cell disease are not at equal levels of risk. Patients with a history of pain, as well as individuals with coexisting organ conditions, need to be even more careful to avoid Covid-19 infection than those without any comorbidities," Mucalo said.For the study, the team assessed reports on 750 children and adults between March 2020 and March 2021.About half of the patients were taking hydroxyurea, and the researchers found that hydroxyurea use was associated with lower risk of presenting with pain during Covid-19 in adults living with SCD.However, hydroxyurea did not affect whether an individual would develop a serious case of Covid-19 or need to be hospitalised in children or adults. Further studies are needed to understand the effects of hydroxyurea, they said.