Prof Ugur Sahin, BioNTech co-founder, also raised hopes the jab could halve transmission of the virus, resulting in a "dramatic reduction in cases".
Last week, BioNTech and co-developers Pfizer said preliminary analysis showed their vaccine could prevent more than 90% of people from getting Covid-19.
About 43,000 people took part in tests.
"I'm very confident that transmission between people will be reduced by such a highly effective vaccine - maybe not 90% but maybe 50% - but we should not forget that even that could result in a dramatic reduction of the pandemic spread," he said.
The UK is expected to get 10 million doses of the BioNTech/Pfizer vaccine by the end of the year, with a further 30 million doses already ordered. The jab, which was trialled in six countries, is given in two doses, three weeks apart.
Older residents and staff in care homes are likely to be prioritised, followed by health workers and the over-80s. People would then be ranked by age.
After the announcement of the world's first effective vaccine came on Monday, Sir John Bell, regius professor of medicine at Oxford University, suggested life could be back to normal by spring.
"I am probably the first guy to say that, but I will say that with some confidence," he said.
However, Prof Sahin said it would take longer.
If everything continued to go well, he said, the vaccine would begin to be delivered at the "end of this year, beginning of next year".
He said the goal was to deliver more than 300 million doses worldwide by next April, which "could allow us to only start to make an impact".
He said the bigger impact would happen later, adding: "Summer will help us because the infection rate will go down in the summer and what is absolutely essential is that we get a high vaccination rate until or before autumn/winter next year."
Prof Sahin said it was essential that all immunisation programmes were completed before next autumn.