Photo/Illutration Dexamethasone, a steroid drug for pneumonia patients (Asahi Shimbun file photo)

Steroids can exacerbate symptoms of COVID-19 and increase the risk of death if they are administered too early, studies in Japan and abroad have shown.

Doctors are urging patients who were prescribed steroids before recuperating at home to follow the instructions on when to take the drugs.

Steroids reduce damage to organs caused by an overreaction of the immune system. Proper timing is essential, the doctors say, because steroids suppress the immune system.

In Japan, dexamethasone and other steroids have been approved to treat COVID-19 patients with “moderate II” symptoms, which require oxygen inhalation due to severe pneumonia, and those in serious condition who are put on ventilators.

According to health ministry data, more than 20,000 COVID-19 patients were hospitalized nationwide at the height of the fifth wave of infections in summer.

Experts have long raised concerns that steroids could exacerbate COVID-19 symptoms if they are administered to “moderate I” patients or others in less severe condition who do not require oxygen inhalation.

In a study published in September in the U.S. scientific journal Plos One, a team of researchers from Chiba University and other institutions reported that symptoms of the disease could worsen if patients receive steroids before antiviral drugs: (

The team analyzed data of about 70 COVID-19 patients admitted to Chiba University Hospital and found that those who were administered steroids first were more than twice as likely to be put on ventilators or treated at ICUs than those who received antiviral drugs first.

Another group of researchers from Veterans Affairs hospitals in the United States and other institutions reported in July that administering steroids increased the mortality rate among COVID-19 patients who did not require oxygen administration.

The study, which was published at ( before being peer-reviewed, was based on analyses of about 9,000 inpatients.

It showed that patients who received steroids were roughly twice more likely to die within 90 days than those who were not administered the drugs.

“Steroids are effective in treating patients who require oxygen administration, but the drugs could do harm to them if given too early,” said Yosuke Matsumura, who heads Chiba Emergency Medical Center’s intensive care department, which treats serious COVID-19 cases.

“The drugs may still have been administered at some medical institutions without checking the latest scientific evidence.”

Many patients with pneumonia who would normally require hospitalization have been forced to recuperate at home since the fourth wave of novel coronavirus infections, which hit Japan this spring.

In May, the health ministry released its new guidelines for COVID-19 treatment that allowed such patients to take steroids at home. It revised the guidelines in August to say that doctors can prescribe steroids to patients in advance to help deal with sudden changes in their conditions.

“The drugs should be given to inpatients whose conditions can be constantly monitored after the administration,” said Toshibumi Taniguchi, an associate professor at Chiba University Hospital’s Department of Infectious Diseases.

“It’s unavoidable to allow patients to take the drugs at home as a last resort when hospitals are being overwhelmed, but it’s important to make sure that they understand the risks.”

Patients recuperating at home can take steroids if their blood-oxygen levels, measured by pulse oximeters, are 93 percent or lower, according to the ministry’s guidelines.

The guidelines also ask doctors to ensure patients meet the criteria for steroid use and inform them on when to take the drugs through phone or online medical examinations.