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Britain on Wednesday announced it would provide genomic sequencing support to Brazil, Ethiopia, Kenya, Nigeria and Pakistan to help identify vaccine-busting variants of Covid-19.
Public Health England said the five countries would benefit from a programme that aims to track changes in the virus.
It said the support would vary for each country but would generally include the supply of reagents – a substance that causes a chemical reaction in test tubes – and other equipment to boost sequencing capability.
Training and advice will also be provided.
Britain is considered to be a world leader in genome sequencing. About a third of all Covid-19 sequences submitted to an international database come from the UK.
The novel coronavirus mutates every few weeks, slower than influenza or HIV but enough to require tweaks to vaccines.
Public Health England has already sequenced samples from Ukraine, Kyrgyzstan, Tajikistan and Albania, and the programme will be extended.
The UK is also in talks with Singapore about creating a partnership for sequencing in South-east Asia.
Dr Jenny Harries, chief executive of the UK Health Security Agency, said new Covid-19 variants were a "major threat" to Britain.
“Strong surveillance is vital to controlling the transmission of the virus and international co-operation is crucial in developing a system that works to protect all of us," she said.
Foreign Secretary Dominic Raab said Britain was "a science superpower and it is right we support the worldwide fight against Covid-19".