Covid-19 vaccines prevented almost 20 million deaths globally in the first year they were available, a mathematical modelling study finds.

Using Covid-19 death records and total excess deaths from 185 countries and territories, researchers from the Medical Research Council Centre for Global Infectious Disease Analysis at Imperial College London said the study was the first to assess deaths averted directly and indirectly from COVID-19 vaccination.

Vaccinations prevented 14.4m deaths across the 185 countries and territories from 8 December 2020 to 8 December 8 2021, based on official reported Covid-19 deaths, the study authors reported in The Lancet Infectious Diseases.

'This estimate rose to 19.8m deaths from Covid-19 averted when we used excess deaths as an estimate of the true extent of the pandemic, representing a global reduction of 63% in total deaths (19.8 million of 31.4 million) during the first year of Covid-19 vaccination,' they wrote.

However, there were 96 countries and administrative regions where vaccination coverage fell below the WHO target of 40% by the end of 2021, with researchers estimating a further 599,300 deaths would have been averted if this target had been met.

'In low-income countries, we estimated that an additional 45% of deaths could have been averted had the 20% vaccinations coverage target set by [Covid-19 Vaccine Access initiative] COVAX been met by each country, and that an additional 111% of deaths could have been averted had the 40% target set by WHO been met by each country by the end of 2021,' they wrote.

'Covid-19 vaccination has substantially altered the course of the pandemic, saving tens of millions of lives globally… Despite this, more lives could have been saved if vaccines had been distributed to more rapidly to many parts of the world and if vaccine uptake could have been strengthened worldwide.'

Study co-first author Gregory Barnsley, from Imperial College London, said that quantifying the global impact of vaccination was challenging because access to vaccines varied between countries, as did information about which Covid-19 variants had been circulating, as many countries had limited genetic sequence data.

'It is also not possible to directly measure how many deaths would have occurred without vaccinations. Mathematical modelling offers a useful tool for assessing alternative scenarios, which we can’t directly observe in real life,' he said in a statement.

Co-author Professor Azra Ghani, chair in Infectious Disease Epidemiology at Imperial College London, said that whilst the intense focus on the pandemic had now shifted, it was important to ensure the most vulnerable people globally were protected from Covid-19 and other major diseases that continued to disproportionately affect the poorest.

'Ensuring fair access to vaccines is crucial, but requires more than just donating vaccines,' he said in a statement.

'Improvements in vaccine distribution and infrastructure, as well as coordinated efforts to combat vaccine misinformation and improve vaccine demand, are needed. Only then can we ensure that everyone has the opportunity to benefit from these life-saving technologies.'

The study comes as the UK faces a new wave of Covid, with health experts warning one in five people aged 75 years and over have not received a vaccine within the past six months, putting them more at risk of severe disease. NHS England has this month set out its preliminary plan for an autumn booster programme, with pharmacies able to apply to deliver booster jabs.