More than 300 million doses of the coronavirus vaccines have been administered, in more than 100 countries worldwide.

However, there are vast differences in the pace of progress in different parts of the world. Some countries have secured and delivered doses to a large proportion of their population – but many more are still waiting for their first shipments to arrive.

With an aim to give doses to nearly every adult around the world, this is the largest-scale vaccination programme in history.

The US and China have administered the highest number of doses, 90 million and 52 million respectively. The UK ranks third, with more than 23 million.

Many poorer countries are relying on deliveries from Covax, an international scheme led by the World Health Organization (WHO) which is trying to ensure everyone in the world has access to a Covid vaccine. Ghana became the first country to receive vaccines through this programme on 24 February.

Covax plans to deliver about two billion vaccine doses globally by the end of the year, but many vaccines require two doses per person.

The vaccine produced by Pfizer and BioNTech was the first approved by the WHO.

It is still the vaccine being given in the most countries, but several others have been approved for use.

Most governments are starting with doses for the over-60s, health workers and people who are clinically vulnerable. In countries such as Israel and the UK, there are already promising signs the vaccines are reducing hospital admissions and deaths as well as community transmission.

Worldwide, more than 200 vaccine candidates are undergoing trials to test their efficacy and safety.