BRUSSELS (Reuters) - The European Union on Wednesday threatened to take tougher measures to curb the export of COVID-19 vaccines, escalating an ongoing row with Britain and the Unites States over their restrictive handling of vaccine deliveries to the 27-nation bloc. “If this situation does not change, we will have to reflect on how to make exports to vaccine-producing countries dependent on their level of openness,” EU Commission President Ursula von der Leyen told a news conference. She said Europe just wants to make sure it gets its fair share. “We are ready to use whatever tools we need to deliver on that,” von der Leyen said. She warned that the bloc “will reflect on whether exports to countries who have higher vaccination rates than us are still proportionate”. In the six weeks from Jan. 30, when the EU put in place a system requiring authorisation of vaccine exports, drugmakers shipped 9.1 million doses to Britain and 1 million to the United States from EU plants.