A big win-win": Vaccine sharing could protect against future COVID-19 waves

“For high-income countries, donating a small portion of vaccines to low- and middle-income countries could better lower the risk of future waves than waiting for the epidemic to be controlled in their own countries.”
As of 31 December 2021, more than nine billion doses of the COVID-19 vaccine had been administered worldwide – approximately 116 doses for every 100 people – but the distribution of those doses has been highly skewed toward people in high-income countries. More than 70% of people in these countries are fully vaccinated, compared to 4% in low-income countries.

Using a mathematical model, Qingpeng Zhang and colleagues at the Chinese Academy of Sciences in Beijing projected the consequences of such vaccine inequity over five years, against the backdrop of evolving strains of SARS-CoV-2 and ongoing international travel.

The research, published in Nature Human Behaviour, suggested that the strategy of trying to vaccinate everyone in certain countries at the expense of those living elsewhere is ill-conceived. Although there is a short-term benefit in terms of a reduction in deaths in the first year, as highly-vaccinated populations gradually become more vulnerable as new strains emerge, the duration of the pandemic overall increases.

Conversely, equitable vaccine allocation could substantially curb the spread of new variants, Zhang and colleagues argue. They calculated that increasing vaccine donations to 46% of total high-income countries’ vaccine supply would lead to substantial decreases in deaths in low- and middle-income countries, and would protect all countries against new SARS-CoV-2 strains and pandemic waves.