Strong sales of its COVID-19 vaccine and other medicines helped Pfizer nearly double its second-quarter revenue and boost its profit an impressive 59%, beating Wall Street expectations and leading the drug giant to sharply hike its 2021 sales and profit forecasts. Amid the surging coronavirus pandemic, the COVID-19 vaccine became Pfizer's top seller, bringing in nearly half its revenue $7.84 billion from direct sales and revenue split with its partner, Germany's BioNTech. Pfizer now anticipates revenue from the two-dose vaccine this year to reach $33.5 billion for the 2.1 billion doses it's contracted to provide by year end. That doesn't include a contract struck last week to provide an additional 200 million doses to the U.S. The New York company on Wednesday disclosed that ongoing testing of a booster shot, given six months after the second vaccine dose, showed it raised antibody levels against the more-transmissible Delta variant to 11 times higher in older people and five times higher in younger people, compared to levels after two doses. Pfizer has delivered more than 1 billion doses of the vaccine globally and expects to make 3 billion doses this year, with many more going to low- and middle-income countries from now through year's end. Most doses of all the COVID-19 vaccines produced in Europe and the U.S. so far have gone to wealthy countries.