Pfizer Inc. raised this year’s sales forecast for its coronavirus vaccine to roughly $26 billion, a 73% gain that reflects the shot’s climbing role in a long-term global vaccination campaign.International demand for Covid-19 vaccines will remain in force for at least a few more years as people seek to maintain their protection as the virus courses, Pfizer Chief Executive Albert Bourla stated on Tuesday on an earnings conference call with analysts. Booster shots likely will be required some time at least six months after being vaccinated, and then annually moving forward, Mr. Bourla stated. Demand for vaccines still may move forward, given that the push to get shots in the arms of people around the world is shaping up as a yearslong process with plenty of challenges, especially in poorer countries, Mr. Bourla stated. While the US has vaccinated over 40% of its adult population, much of the rest of the world remains in the early phases of vaccinations.The surge of coronavirus infections in developing countries such as India amid a relative scarcity of the vaccine supply means that the pandemic will continue until mid-2022, according to the chief executive of BioNTech SE, which co-developed Pfizer’s Covid-19 vaccine.