Pfizer's COVID-19 vaccine this week set high efficacy expectations, but the vaccine has stringent storage needs and requires two doses, creating significant challenges for a global vaccination campaign. If they prove themselves in the clinic, later-arriving shots from the likes of Sanofi, J&J and Novavax may be better suited for global distribution.
Johnson & Johnson’s vaccine is in testing as a one- and two-dose regimen, for instance, and is expected to be stable at refrigerated temperatures of 35.6 to 46.4 degrees Fahrenheit. When J&J started its phase 3 trial in September, the company said the candidate is "compatible with standard vaccine distribution channels and would not require new infrastructure to get it to the people who need it.” Now, J&J is performing studies to confirm that expectation, a spokesman said.
Sanofi and GSK’s program, a two-dose recombinant protein vaccine with an adjuvant, can be stored between 35.6 to 46.4 degrees Fahrenheit, or in a doctor’s office or pharmacy, a spokeswoman said. While the partners aren't expected to be the first to deliver doses, execs have said they expect to play an important role in the global immunization push.
AstraZeneca is conducting stability and shipping studies to determine requirements for its vaccine, a spokesman said. The company expects final multi-dose vials "will require refrigeration to ensure product quality, which will involve a reliable, flexible cold chain during transport," he added.
Novavax says its candidate, NVX-CoV2373, can be stored at refrigerated temperatures, "allowing for successful cold chain management with existing infrastructure."
The new class of mRNA vaccines requires colder storage—in Pfizer and partner BioNTech's case, much colder. Pfizer’s vaccine must be kept at minus 94 degrees Fahrenheit (minus 70 degrees Celsius), and will only last for 24 hours at refrigerated temperatures between 35.6 and 46.4 degrees Fahrenheit.
Some countries—and some hospitals in the U.S.—have said they don’t have enough ultracold storage capacity to make a large vaccination campaign feasible, or even possible in some places.
Sanofi is also advancing an mRNA program with Translate Bio; that shot must be stored at an even colder 112 degrees below zero Fahrenheit. But a spokeswoman said the team is “working on improving the stability of the mRNA vaccine candidate,” and is targeting a storage temperature of minus 4 degrees Fahrenheit.
Moderna’s shot, another late-stage mRNA program, must be stored at minus 4 degrees Fahrenheit. The company expects to post its first efficacy data this month.
CureVac's mRNA candidate doesn't have such hefty storage requirements, though. The vaccine is stable for at least three months at refrigerated temperatures, and for up to 24 hours at room temperatures, the German biotech said Thursday.
Despite the challenges of its cold-storage needs, Pfizer has an ambitious plan to deliver hundreds of millions of doses in the coming months and into 2021. The company is sidestepping the U.S. federal government’s logistical push, instead opting to set up its own supply chain that uses experienced shipping partners, newly designed storage containers and a fleet of trucks to get doses to vaccination sites.
Pfizer has supply deals in place with the U.S., Europe, U.K., and Japan. The company expects to produce 50 million doses in 2020 and 1.3 billion doses in 2021.
But because of the cold chain requirements and logistical challenges of a two-dose regimen, some experts have said the Pfizer program will be mostly for the rich.
In the U.S., much of the financial responsibility for vaccination campaigns will fall on states, which will need more money from the federal government to make it work, the Chicago Tribune reports.
In places such as India, the vaccine’s storage requirements make a large vaccination campaign unrealistic, according to reports. A Pfizer spokesperson told India's Business Standard the company is looking at ways to make it available there.
Meanwhile, Asian health officials have told Reuters they aren’t holding out hope that the Pfizer shot will be an immediate solution in their countries, and the news service reports that the rollout could also face issues in Latin America and Africa.
Editor's note: Details about CureVac's vaccine were added Thursday.