London, Nov 15 : Normalcy from the Covid era can only be expected by next year's winter as any Covid vaccine will take to show its effect and will not immediately reduce the number of infections, as per the co-developer of Pfizer's vaccine, media reports said. A new Covid vaccine's impact will work significantly over the summer and life should be back to normal by next winter, Prof Ugur Sahin, co-founder of BioNTech, whose vaccine candidate has proved to prevent over 90 per cent people from getting Covid-19, as per preliminary reports. The Pfizer-BioNTech is one of the 11 vaccines in their final tests. This winter would still be hard, he said in an interview on the BBC's Andrew Marr Show. Sahin said he was confident the vaccine would reduce transmission between people as well as stop symptoms developing in someone who has had the vaccine, though not as high as the test results but still "maybe 50 per cent". He said as everything continued to go well, he said, the vaccine would begin to be delivered at the "end of this year, beginning of next year". The goal was to deliver more than 300 million doses worldwide by next April, he said on the BBC show, which "could allow us to only start to make an impact" and the bigger impact would happen later only. "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," he stressed. 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 vaccine's second shot is administered. 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. /IANS