Cyber attackers have targeted the cold supply chain needed to deliver COVID-19 vaccines, according to a report detailing a sophisticated operation likely backed by a nation-state.

The hackers appeared to be trying to disrupt or steal information about the vital processes to keep vaccines cold as they travel from factories to hospitals and doctors’ offices.

According to the report by IBM’s threat intelligence task force, which advises companies and the public sector on cyber security, they targeted organizations associated with a cold chain platform run by the Gavi vaccine alliance, a public-private partnership for developing immunization for poorer countries.