Pfizer's COVID-19 vaccine generated $3.5 billion in revenue in the first quarter of 2021, which was nearly a fourth of the company's $14.6 billion income during the period, the pharmaceutical giant reported in an earnings call Tuesday.

Why it matters: The vaccine was the biggest source of revenue for Pfizer — which, unlike some of its competitors — elected to collect the profit from sales of its vaccine, the New York Times notes.

• Pfizer's operational revenues grew by 8% in the first few months of the year.
• Also unlike some of its competitors, the company did not to take federal funds from the Trump administration's Operation Warp Speed.

The big picture: Pfizer's vaccine "is disproportionately reaching the world’s rich" the New York Times reports, citing broad figures from the World Health Organization.

• Vaccines produced by China, India and Russia have become the primary source of doses delivered to poorer nations.
• Pfizer announced Tuesday it has shipped 430 million doses of the vaccine to 91 countries and territories around the world, though it did not specify how much have gone to developing nations.