What’s Next for the Pfizer/BioNTech Vaccine?

It’s difficult to improve on a vaccine with 95 percent effectiveness, but Kathrin Jansen, senior vice president and head of vaccine research and development at Pfizer, says important work still lies ahead on the Pfizer and BioNTech’s breakthrough mRNA vaccine for preventing Covid-19.  Even as administration of the Pfizer vaccine, developed in collaboration with the German biotechnology company BioNTech, rolls out across the United States and around the world, Jansen and her colleagues have a clear agenda. They need to maintain high levels of protection in an ever-changing pandemic landscape, and to ease challenges associated with transporting and delivering their vaccine.

“There’s a lot that remains to be evaluated,” Jansen said during a symposium, The Quest for a Covid-19 Vaccine, hosted by the New York Academy of Sciences. “We’d like to understand the vaccine’s protection against asymptomatic infection,” she added, just one of several key assessments planned in the coming months. Jansen also identified testing safety and efficacy in pediatric populations as other priorities. While Phase 3 trials of the Pfizer/BioNTech vaccine were diverse, capturing a wide range of ages, ethnicities, and patients with stable chronic illnesses, clinical trials for children 12-15 are only now underway, with trials for younger children to follow.

The difficult logistics of transporting, thawing, and delivering a vaccine that requires storage temperatures colder than the average Arctic winter are not lost on the Pfizer team. Jansen reported that the company is “currently working and making progress on a vaccine formulation that would require less cold storage temperatures.”

Recently, several new, more transmissible variants of SARS-CoV-2 have emerged—notably in the United Kingdom and South Africa—prompting vaccine researchers and developers to examine the implications for vaccine effectiveness. Addressing what she deems a “very hot topic,” Jansen explained that gathering data on vaccine effectiveness against new variants often takes time—a lag that she and other developers circumvent by using synthetic biology techniques. They design “pseudovirions,” or recombinant viruses sporting the same mutations seen in the new variants, and then test the neutralization capabilities against blood sera from vaccinated people in the lab. Experiments utilizing these approaches showed reassuringly strong results for the current vaccine against psuedovirions having the key mutations found in the UK and South African variants, Jansen said. But she cautioned that there is no substitute for research on authentic variants and real-life surveillance.

Jansen said “we need to be ready” for the possibility that a SARS-CoV-2 variant causes disease that escapes protection from the current vaccines, such that existing vaccines must be modified. Unprecedented levels of international scientific collaboration have been a hallmark of this pandemic, and Jansen said “an ongoing, real-time” multi-national effort will be critical to identify concerning variants, and to share genetic sequences and vaccine protection data.  She noted that Pfizer and other companies are working closely with regulators in hopes of devising a “streamlined plan” to quickly modify a vaccine if necessary and to generate any data needed to support regulatory authorization or approval. But first, “we need to work out what actually would be the trigger—what data do we need to see that would indicate ‘yes’, [or] ‘we ‘need to update,’ or ‘no’, the vaccines are perfectly capable and effective in their current form,” Jansen said.  Only time, research, and, unfortunately, more infections, will tell.