Vaccine inequity is the biggest challenge to ending the Covid-19 pandemic and recovering from it, the World Health Organization (WHO) chief said Thursday.

WHO Director-General Tedros Adhanom Ghebreyesus issued his statement from Geneva along with data released by the UN Development Program (UNDP) and the University of Oxford.

Covid-19 vaccine inequity will have a lasting and profound impact on socio-economic recovery in low- and lower-middle-income countries without urgent action to boost supply and assure equitable access for every country, including through dose-sharing, the group said.

"Economically, epidemiologically and morally, it is in all countries' best interest to use the latest available data to make lifesaving vaccines available to all," Tedros said.

Accelerated manufacturing and sharing enough vaccine doses with low-income countries could have added $38 billion to their GDP forecast for 2021 if they had similar vaccination rates as high-income countries, the group said.

Read: Vaccine inequity undermining global economic recovery, shows new data

At a time when richer countries have paid trillions in stimulus to prop up flagging economies, now is the time to ensure vaccine doses are shared quickly, it urged.

The group called for removing barriers to increase vaccine manufacturing and secure financing support so vaccines are distributed equitably for a truly global economic recovery to occur.

"In some low- and middle-income countries, less than 1% of the population is vaccinated – this is contributing to a two-track recovery from the pandemic," UNDP Administrator Achim Steiner said.

New data from entities, including the International Monetary Fund, World Bank, Unicef, and Gavi, the vaccine alliance, show richer countries are projected to vaccinate quicker and recover economically quicker from the pandemic.

At the same time, poorer countries have not been able to vaccinate their health workers and most at-risk population and may not achieve pre-Covid-19 levels of growth until 2024.

"Meanwhile, Delta and other variants are driving some countries to reinstate strict public health social measures," said the statement. "This is further worsening the social, economic and health impact, especially for the most vulnerable and marginalised people."

The Global Dashboard for Covid-19 Vaccine Equity – an initiative by the UNDP, WHO, and the Oxford University's Blavatnik School of Government – combines the latest Covid vaccination information and socio-economic data, Achim said. "It illustrates why accelerating vaccine equity is critical to saving lives and driving a faster and fairer recovery from the pandemic with benefits for all."

Read: Vaccine inequity: Inside the cutthroat race to secure doses

The group also said a high price per Covid-19 vaccine dose relative to other vaccines and delivery costs – including the health workforce surge – could place a massive strain on fragile health systems and undermine routine immunisation and essential health services.

"The pandemic is a test, and the world is failing, as 75% of the vaccine shots delivered globally so far were in only 10 countries," said Tedros in a speech to an International Olympic Committee meeting Wednesday.

He warned anyone who believed the pandemic was over because it was under control in their part of the world lived in "a fool's paradise."

The world needs to produce 11 billion doses next year and the WHO wanted governments to help reach a target of vaccinating 70% of people in every country by the middle of next year.