The World Health Organization approved two new Covid-19 treatments on Friday, growing the arsenal of tools along with vaccines to stave off severe illness and death from the virus.

The news comes as Omicron cases fill hospitals around the world with the WHO predicting half of Europe will be infected by March.

In their recommendation in British medical Journal the BMJ, WHO experts said arthritis drug baricitinib used with corticosteroids to treat severe or critical Covid patients led to better survival rates and reduced need for ventilators.

Experts also recommended synthetic antibody treatment Sotrovimab for people with non-serious Covid at highest risk of hospitalisation, such as the elderly, people with immunodeficiencies or chronic diseases such as diabetes.

Sotrovimab's benefits for people not at risk of hospitalisation were deemed insignificant and the WHO said its effectiveness against new variants like Omicron was "still uncertain".

Only three other treatments for Covid-19 have received WHO approval, starting with corticosteroids for severely ill patients in September 2020.

Corticosteroids are inexpensive and widely available and fight inflammation that commonly accompanies severe cases.

Arthritis drugs tocilizumab and sarilumab, which the WHO endorsed in July, are IL-6 inhibitors that suppress a dangerous overreaction of the immune system to the SARS-CoV-2 virus.

Baricitinib is in a different class of drugs known as Janus kinase inhibitors, but it falls under the same guidelines as the IL-6 inhibitors.

"When both are available, choose one based on issues including cost and clinician experience," the guidelines say.

Synthetic antibody treatment Regeneron was approved by the WHO in September and the guidelines say Sotrovimab can be used for the same type of patients.

The WHO's Covid treatment recommendations are updated regularly based on new data from clinical trials.

US billion Covid tests

US President Joe Biden on Thursday said the government will double its purchase of Covid-19 tests with an extra 500 million kits, bringing the total to one billion.

As the United States struggles against the Omicron variant sweeping the world, Biden urged Americans to wear good quality masks as "part of your patriotic duty."

However, the White House faces pressure over the lack of easily available Covid tests, stymying efforts to keep schools open and get people to work when Omicron infections are surging.

Biden defended the response, saying about 15 million tests were being administered every day, compared to two million when he took office a year ago.

"Today I'm directing my team to procure an additional 500 million more tests to distribute for free," he said. The tests will be available via a soon-to-be launched government website, he said.

Ending his remarks at the White House, Biden made "a special appeal to social media."

"The misinformation and disinformation. It's on your shows -- it has to stop," he said.

"It's been a long road but what's clear is that the way we get through this is everybody does their part..., no matter your political party," he said.