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, reports BBC.
In an interview on BBC One's Andrew Marr Show, Prof Sahin said he expected further analysis to show the vaccine would reduce transmission between people as well as stop symptoms developing in someone who has had the vaccine.
"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.
The UK government announced another 24,962 confirmed Covid-19 cases on Sunday, as well as a further 168 deaths within 28 days of a positive test.
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.
The vaccine has given a boost of confidence that an end to the pandemic is close, with the leading scientist behind it hopeful life could return to normal by next winter.
But there are some big uncertainties.
The vaccine needs approval from regulators - and they will only grant that if they're happy the jab is safe and works well. Early results look very good, but we await the full ones in the coming weeks.
There is also no data yet to show how well the jab works in those who need it the most - the elderly.
Nor do we know if it stops people spreading the disease, as well as getting sick.
And it's not clear how long immunity might last. People might need yearly boosters.
If the vaccine is rolled out, it will take time to immunise and protect enough people.
Other Covid-19 vaccines may come along that work just as well or even better than this new vaccine.
But it is possible that by the summer, mass immunisation will be well under way and we could start to reap the benefits.
Asked if the vaccine was as effective in older people as it is in younger people, he said he expected to have a better idea in the next three weeks.
He said it was not yet known how long immunity would last after the second dose of the vaccine is given.
However, he said, a booster immunisation "should not be too complicated" if it was found immunity was reduced significantly after one year.
Prof Sahin also said the "key side effects" of the vaccine seen so far were a mild to moderate pain in the injection site for a few days, while some participants had a mild to moderate fever over a similar period.
"We did not see any other serious side effects which would result in pausing or halting of the study," he added.
His vaccine is one of 11 currently in the final stages of testing.
It will not be released for use in the UK until it passes final safety tests and gets the go-ahead from the Medicines and Healthcare products Regulatory Agency (MHRA). The agency’s head said it would not lower its safety standards despite the need to get a vaccine quickly.
If it was approved, the NHS would be ready to roll out the vaccine from December, Health Secretary Matt Hancock said.
Prime Minister Boris Johnson has urged people not to slacken their resolve in the meantime, saying the vaccine’s development ‘cleared’ on significant hurdle but there are several more to go".
Meanwhile, concerns have been raised that mutated forms of the virus might hamper the effectiveness of future vaccines.
It comes after 12 people found with a mink-related strain of the virus following an outbreak in Denmark.
Virology professor Wendy Barclay, a scientific adviser for the government, said there was a "worry" that the vaccines currently under development "won't work quite so well as the virus continues to evolve".
This did not mean vaccines would not work at all, she added, but adaptable and fast-responding jabs could be the best option.
It wants financial and criminal penalties for social media firms that do not remove false scare stories about vaccines.
Shadow health secretary Jonathan Ashworth said such content was "exploiting people's fears, their mistrust of institutions and governments and spreading poison and harm".
His party wanted to work with the government on a cross-party basis to build trust and help promote take-up of the vaccine, he said.
The government said it took the issue "extremely seriously" with "a major commitment" from Facebook, Twitter and Google to tackle anti-vaccine content.
Many social media platforms label false content as misleading or disputed - and all remove posts that contravene terms of service.
Also read: Europe, Gates pledge funds to get vaccines to poor nations