Wall Street analysts assume the $19.50 per dose price for Pfizer’s coronavirus vaccine candidate sets a benchmark, but a former HHS vaccine official cautioned that HHS may insist on a much lower price for future purchases. The initial contract may pay a “speed premium” for extremely fast development, and Pfizer has not taken federal funding like other companies. HHS announced this week that it will pay $1.95 billion for 100 million doses of a coronavirus vaccine candidate being developed by...