The G7 group of wealthy countries plans to donate one billon doses of coronavirus vaccine to the developing world.

Britain will give 100 million doses, the prime minister said today, adding that the UK has led efforts to vaccinate poorer nations against Covid-19.

But charities have accused rich countries of doing too little, too late to stop the spread of the pandemic around the world at a time when the global vaccination drive is in crisis.

How bad is it?

Covax, a vaccine-sharing protocol created by the World Health Organization and other partners, is the main international framework for getting jabs to lower-income countries.

The idea was to prevent the richest countries from buying up global stocks of vaccines and forcing poorer nations to wait.

Covax has failed to hit a number of vaccine delivery targets so far.

The original objectives were to deliver two billion doses of vaccines to countries around the world in 2021, and a further 1.8 billion doses to 92 lower-income countries by early 2022.

The latest figures show that just 83.6 million doses have been shipped so far – less than five per cent of the target for this year.

There is a correlation between income and vaccination rate: many of the countries that have vaccinated the most citizens are wealthy nations like Britain and the US. The countries with the lowest coverage are among the world’s poorest.

Covax has so far failed to hit its initial target of vaccinating three per cent of each country’s population, which is considered the minimum level of coverage that would protect frontline healthcare workers.

Dozens of countries that have signed up to Covax do not have enough vaccine doses to hit this target, according to Unicef figures.

Why has the rollout been slow in developing countries?

There is only so much vaccine available, and rich countries who signed early bilateral contracts with the manufacturers have ordered a disproportionate amount of it.

According to Unicef, Britain, the EU and the US together have bought half the current supply of vaccines available on the world market.

The small number of pharmaceutical companies involved in the global vaccine supply means problems with one manufacturer can have far-reaching consequences.

In April, the Indian government banned exports of Oxford/AstraZeneca vaccine produced by the country’s Serum Institute amid a surge in cases.

The sudden pinch on supply from this major manufacturer hit vaccination programmes around the world, including the UK.

In a joint statement, the heads of the organisations that run Covax said problems with the Indian supply chain would create a shortfall of 190 million doses for the facility by the end of this month, which they warned could prove “catastrophic” for poorer countries.

Is Britain leading the way?

The UK has responded to calls from Covax for urgent assistance by promising to begin donating surplus vaccine to the developing world immediately.

Boris Johnson said the UK would give five million doses by the end of September, 25 million more by the end of this year, and 100 million doses in total within the next year.

It is the first time Britain has directly given away excess vaccine doses.

As the prime minister told reporters today, the UK is one of the largest financial contributors to Covax, and British taxpayers helped fund the development of the Oxford/AstraZeneca jab.

This is one of the main vaccines being distributed among poorer countries, partly thanks to its low price.

Oxford University and AstraZeneca have pledged to “provide the vaccine on a not-for-profit basis for the duration of the pandemic across the world, and in perpetuity to low- and middle-income countries”.

But critics have called on Britain and other richer countries to do more.

Oxfam said today that halting the pandemic will require 11 billion doses of vaccine worldwide, not the 3.8 billion promised by Covax.

The facility’s medium-term objective of vaccinating 20 per cent of people in participating countries falls short of the level of coverage many scientists predict will be needed to achieve herd immunity.

A coalition of charities is urging governments to force pharmaceutical companies to waive their intellectual property rights on vaccines, allowing them to be produced more cheaply and in greater numbers around the world.

France and the US have said they support a waiver on vaccine patents, whereas Britain and other EU countries are against the move.

Will the donations count as foreign aid?

The government said today that the cost of donating surplus vaccine would be classified as Official Development Assistance (ODA), more commonly known as the overseas aid budget.

Ministers controversially decided to restrict aid spending to 0.5 per cent of national income rather than 0.7 per cent this year.

Some aid experts have warned against counting vaccine donations as ODA, saying it could lead to cuts to other aid programmes.

But a Downing Street press release said the new vaccines commitment would be in addition to the £10 billon of aid the government has already committed, suggesting total aid spending will now rise above the 0.5 per cent threshold.