This week's brief roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for COVID-19, the illness caused by the new coronavirus, focuses on the importance of lockdown measures, other diseases which heighten the risk of severe infection and various symptoms observed in patients.

Symptoms linger for weeks even in mild cases

COVID-19 patients not sick enough to be hospitalized are advised to isolate themselves for 14 days, but their symptoms often last much longer, doctors in Atlanta have found. They kept track of 272 non-hospitalized coronavirus patients with follow-up phone calls every 12 to 48 hours for up to 50 days. Three weeks after initial symptoms emerged, 41% of patients still had a cough, 24% had shortness of breath on exertion, 23% still had a loss of smell or taste, 23% had sinus congestion and 20% reported headache.

Diarrhea was less common but still affected some patients beyond three weeks. In a report posted last week on the preprint server medRxiv, without peer review, the researchers note they lacked such details as to whether symptoms waxed and waned, and they depended on patient self-reporting, which may be less accurate.

"Patients and health care providers should be aware that symptom resolution may be gradual," they said, and frequently last longer than the minimum recommended duration of isolation. They did not address how contagious patients might be as symptoms linger beyond 14 days.

Lockdowns likely saved millions of lives

Wide-scale lockdowns, including business and school closures, to reduce COVID-19 transmission in Europe may have averted more than 3 million deaths the continent alone, researchers said Monday in the journal, Nature.

Using computer models to estimate the lockdown impact in 11 nations, British scientists said the draconian steps, introduced mostly in March, had "a substantial effect."

A separate study by U.S. scientists, published alongside the European one, estimated that lockdowns in China, South Korea, Italy, Iran, France and the U.S. prevented or delayed around 530 million COVID-19 cases. The authors of the second paper say that while lockdowns "impose large and visible costs on society," the data show "consistent evidence that the policy packages now deployed are achieving large, beneficial, and measurable health outcomes."

Kidney disease yet another risk factor

People with chronic kidney disease should take extra precautions to stay safe from the novel coronavirus, new data from New York City suggest. Doctors analyzed medical records on nearly 3,400 patients who had tested positive for the coronavirus, including 210 with chronic kidney disease. They found that those with poor kidney function were more than twice as likely to require mechanical breathing assistance and more than twice as likely to die. "This tendency was consistent for each age group," they reported in the journal International Urology and Nephrology. Unfortunately, they did not have enough information to tell whether the risks increased as the stage of patients' kidney disease worsened.

IBD does not increase infection risk

People with well-controlled Crohn's disease or ulcerative colitis are no more likely to develop severe COVID-19 than those without these autoimmune disorders, according to a nationwide U.S. study. The conditions, known collectively as inflammatory bowel disease (IBD), affect more than 3 million people in the U.S. alone. IBD is often controlled with strong immunosuppressive drugs that could theoretically put patients at higher risk from the new coronavirus. Small studies have suggested that IBD patients whose disease is under control with these medications do not face higher risks from COVID-19. The new U.S. study of nearly 200,000 people with IBD appears to confirm that.

People with IBD and no evidence of a recent flare-up were not at higher-than-average risk for severe COVID-19, according to a report published last week in the medical journal Gastroenterology. Further, how well they did if hospitalized, and their risk of coronavirus-related death, was similar to COVID-19 patients without IBD. The authors of the paper conclude that IBD patients in remission should stay on their immunosuppressive medications and should exercise social distancing principles like the general population.