BERLIN (Reuters) -BioNTech expects to begin deliveries of two Omicron-adapted vaccines as soon as October, which will help spur demand in the fourth quarter, the German biotech firm said on Monday as it reaffirmed its vaccine-revenue forecast for the year. Demand for the vaccine, 3.6 billion doses of which have been shipped globally, is waning as most people in the Western world have received three or four shots already. However, booster campaigns using upgraded shots specifically targeting the Omicron variant are expected to increase demand in autumn. Pending regulatory approval, BioNTech sai…