Read the passage and answer the following questions.

Alexander Fleming was born in 1881 in Scotland. He went to a small school in a village, and when he left school he didn’t go to university. He worked for five years in an office. But his brother, Tom, was a doctor and helped Fleming to go to university and study medicine. So he went to London University and in 1906 he became a doctor. In 1915, Fleming married Sarah McElroy, an Irish woman. They had one son. During the First World War, many soldiers died in hospital because they didn’t have the right medicines. So after the war, Fleming tried to find a drug that could help them. He worked for many years and in 1928 he discovered a new drug and he called it “penicillin”. He later worked with an Australian and a German scientist to develop a drug that doctors could use. In 1945, they won the Nobel Prize in medicine for their work on penicillin.

When did he win the Nobel Prize in medicine?