The stock exchanges in New York started the new session on Wednesday with minor minuses, after the record levels of the day before.
Pharmaceutical company Pfizer and Wall Street-listed German biotechnologist BioNTech are in the spotlight following news that the UK government has approved their corona vaccine and will use it next week.
Shortly after the opening bell, the leading Dow Jones index was 0.6 percent lower at 29,618 points. The broad S&P 500 dropped 0.4 percent to 3,646 points, and technology gauge Nasdaq dropped 0.8 percent to 12,259 points.
The Pfizer stock won 2.7 percent in the opening minutes, and BioNTech (plus 2.9 percent) also started the day with a profit. Pharmaceutical Moderna (minus 7.6 percent) seemed to be riding along with the positive sentiment around vaccines before the session.
That company applied for approval on Monday for its corona vaccine in the EU and the US. However, the course took a hit when industry peer Merck announced that it had sold its stake in the company.
Data from payslip processor ADP showed that employment in corporate America grew significantly less strongly in November than a month earlier, under pressure from the rising number of corona infections and new lockdowns.