As Pfizer's first COVID-19 vaccine doses roll across the U.S., analysts size up the hurdles ahead

After a “historically eventful” few days for COVID-19 vaccines—featuring key meetings at the FDA and CDC, plus an emergency authorization—a massive immunization program kicked off Monday morning.

Vaccinations with Pfizer and BioNTech's newly-minted shot started in the U.S. Monday— less than 11 months after the country’s first COVID-19 case. While it's a historic moment, and the speed to market has been unprecedented, SVB Leerink analysts point out the hurdles still ahead. 

Despite high efficacy figures for the Pfizer/BioNTech and Moderna vaccines in pivotal studies, there’s “still widespread hesitancy among the general public,” the analysts wrote.

Only about 50% to 60% of the population plans to get the vaccine, surveys show. Even healthcare workers have their own reservations. Recent stories highlighting cases of anaphylaxis and Bell's palsy after vaccination have intensified those concerns, the analysts wrote.

RELATED: It's official: Pfizer, BioNTech COVID-19 shot grabs emergency FDA nod, clearing way for first U.S. vaccinations 

Supply will also be a limiting factor for months. Moderna has said it can make 20 million doses available to the U.S. by the end of the year, and up to 100 million doses by the end of the first quarter of 2021; it agreed Friday to add another 100 million by the end of Q2.

Meanwhile, Pfizer expects to ship 25 million doses in the remainder of 2020 and up to 100 million in the first quarter of next year.

If the companies meet those targets, about 100 million Americans could get vaccines in the first 3 months of 2021, and 50 million in Q2. Both vaccines require two doses.

As Pfizer ships its first doses, Moderna is gearing up for its own FDA advisory committee meeting this week. The company could be shipping doses next week if all goes well, the analysts figure.

And then there are the now-well-known cold-chain requirements for the mRNA vaccines. Pfizer has designed special containers to help its doses stay at ultra-cold temperatures until use, and distributors from air to truck to clinical have been training to handle the vaccine properly on its way to people's arms. 

RELATED: Weak clinical data force Sanofi, GSK to delay COVID-19 vaccine 

While the Pfizer and Moderna programs have succeeded in late-stage testing, the analysts also raised concerns that several of the world’s leading vaccine makers have either suffered R&D setbacks or signaled a willingness to step away from COVID-19 shot research. 

Sanofi and GSK on Friday reported an “insufficient response in older adults” for their partnered vaccine so that program will be tied up in the time-consuming process of finding a correct dose, the analysts pointed out. Australia’s CSL, a leading flu vaccine provider, discontinued its program after it caused false positives on HIV tests.  

Merck & Co. recently said it would have to carefully look at its own prospects in COVID-19, considering the high bar set by Pfizer and Moderna’s programs, the analysts wrote.

And all of that follows a high-profile setback for AstraZeneca: Researchers mistakenly gave a half-sized first dose of its adenovirus vaccine to one group of participants in its phase 3 vaccine, muddying the waters on efficacy and delaying the company's application for an approval.

“This then means that four of the world’s large vaccine companies ... are now removed from the forefront of COVID vaccine development,” the analysts wrote. “Although these actions are justifiable from a research or commercial perspective, we are concerned that there may be only limited backup options” behind Pfizer and Moderna. 

RELATED: AstraZeneca, J&J COVID-19 shots must succeed to meet U.S. vaccination goal: Slaoui 

It’s not surprising for companies to see setbacks through an R&D process, the analysts pointed out. Pfizer, BioNTech and Moderna “have thus far managed quite an operational feat,” they allowed.

Still, even with those companies' successes—and with the setbacks at Sanofi and other companies—Operation Warp Speed head Moncef Slaoui recently said the U.S. will need doses from AstraZeneca and Johnson & Johnson to meet its demand.