Pfizer seems to have struck gold with its double-dose COVID-19 shot. The drug maker on Wednesday raised its sales forecast for the vaccine this year by nearly a third to $33.5 billion. The company said it has signed deals for 2.1 billion doses of the vaccine it jointly developed with Germany’s BioNTech, and that could rise further if it signs more contracts. The pair expect to produce 3 billion doses this year. The vaccine helped Pfizer nearly double its quarterly revenue, accounting for roughly 40% of the total. Pfizer is way ahead in the global race for vaccines. Moderna forecasts full-year sales of over $19 billion; Johnson & Johnson, $2.5 billion. In December, Pfizer was the first to get U.S. emergency authorization for its vaccine.Some rivals have faced manufacturing hurdles.Johnson & Johnson’s vaccine has encountered scrutiny over safety concerns.Pfizer’s sales could rise further next year if it gets approval for a third “booster” dose. It said Wednesday it could file for emergency use authorization for the booster as early as August. As cases of the COVID-19 Delta variant rocket higher, top infectious disease official Anthony Fauci said Sunday that immune compromised Americans may end up needing booster shots.