Currently, the drug dexamethasone is still the only therapeutic shown to be effective against the novel coronavirus for severe patients, the chief of the World Health Organization said Friday.
WHO Director-General Tedros Ghebreyesus addressed journalists at a twice-weekly webinar from Geneva on the fight against the pandemic.
He revealed interim results from the WHO's Solidarity Therapeutics Trial and referred to influenza, which can be countered using some of the same methods as those used against COVID-19.
Tedros also cautioned that demand for influenza vaccines might outstrip supply in some countries, particularly in the northern hemisphere, as Winter arrives.
"The Strategic Advisory Group of Experts on Immunization has therefore recommended that, among the five risk groups, health workers and older adults are the highest priority groups for influenza vaccination during the COVID-19 pandemic," he said.
"Every year, there are up to 3.5 million severe cases of seasonal influenza worldwide, and up to 650,000 respiratory-related deaths."
During this year's southern hemisphere winter, the number of seasonal flu cases and deaths was less than usual due to the measures taken to contain COVID-19.
"But, we cannot assume the same will be true in the northern hemisphere flu season," said the WHO chief.
Turning to the Solidarity Therapeutics Trial, Tedros said it showed that two other drugs, remdesivir and interferon, have little or no effect on preventing coronavirus-related deaths or reducing time in the hospital.
"For the moment, the corticosteroid dexamethasone is still the only therapeutic shown to be effective against COVID-19, for patients with severe disease," said Tedros.
Dexamerhasone is used in the treatment of many conditions, including rheumatic issue, various skin conditions, severe allergies, asthma, chronic obstructive lung disease, croup, brain swelling and eye pain following eye surgery. It is also used with antibiotics in cases of tuberculosis.
He said the Solidarity Trial is the world's largest randomized controlled trial of COVID-19 therapeutics, involving almost 13,000 patients in 500 hospitals in 30 countries.
In June, the WHO chief said the health body had announced it was discontinuing the hydroxychloroquine arm of the study.
Then, in July, it announced it would no longer enroll patients to receive the combination of lopinavir and ritonavir as well.
Tedros said the Solidarity Trial is still recruiting about 2,000 patients every month and will assess other treatments, including monoclonal antibodies and new antivirals.
Regarding the coronavirus, Tedros said that although the number of deaths reported in Europe last week was still less than a quarter of the number reported in the worst week in March, hospitalizations are increasing.
"Many cities are reporting they will reach their intensive care bed capacity in a few weeks," said Tedros.
On Tuesday, the National Institutes of Health, the leading US agency responsible for biomedical and health research, said it had started a study to determine whether certain approved drugs show results against COVID-19.
It said experimental remdesivir had demonstrated clinical benefit for patients.
Remdesivir therapy was used by US President Donald Trump soon after he was admitted to Walter Reed National Military Medical Center following a COVID-19 diagnosis on Oct. 3, White House physician Sean Conley had said at the time.
The COVID-19 pandemic has claimed more than 1.1 million lives in 188 countries and regions since last December.
The US, India, Brazil, and Russia are currently the worst-hit countries.
More than 39 million cases have been reported worldwide, while nearly 27 million patients have recovered, according to figures compiled by the US' Johns Hopkins University.