screengrab fedex vaccine
What it could take to deliver a Covid-19 vaccine to the world
02:29 - Source: CNN
CNN  — 

Vaccines like to be kept cool, none more so than the Pfizer candidate for Covid-19, which has to be deep-frozen. And that’s going to be an issue for developing countries – and for rural areas in the developed world.

The “cold chain” is just one of the challenges in distributing vaccines worldwide.

There are plenty of others: decisions about priority populations and databases to keep track of who’s received what vaccine, where and when. Additionally, different vaccines may have more or less efficacy with different population groups; and governments will need PR campaigns to persuade people that vaccines are safe.

But the logistics of transporting and storing vaccines – getting them from the factory gate to the patient’s arm – are critical. And as most vaccines are likely to require two doses, the whole chain needs must be repeated within weeks.

Unique challenges

The Pfizer-BioNTech vaccine needs to be kept at around -70 degrees Celsius (-94 degrees Fahrenheit) while it’s transported. That’s 50 degrees Celsius colder than any other vaccine currently used.

Moderna says its vaccine can be kept in freezers typically available in pharmacies, and in a refrigerator for 30 days. But there are likely to be fewer doses of the Moderna vaccine than of the Pfizer’s available over the next year.

Phase 3 trials have shown both vaccines to be around 95% effective but the results haven’t yet been reviewed by regulators.

On Wednesday, the CEO of BioNTech, the German biotech company partnering with Pfizer, acknowledged the issue of temperature control.

Employees fill a clinical and pharmaceutical product shipping box with dry ice at the Va-Q-Tec AG factory in Wurzburg, Germany, on November 18.

“We are working on formulation which could allow us to ship the vaccine even maybe at room temperature,” Ugur Sahin told CNN. “We believe that in the second half of 2021 we will have come up with a formulation which is comparable to any other type of vaccine.”

But in the meantime US Health and Human Services Secretary Alex Azar believes the Moderna candidate is “more flexible” for settings like a local pharmacist. Pfizer’s, he said Monday, would be better suited to “big institutional vaccination, say a whole hospital setting, several nursing homes at once.”

Pfizer plans to ship up to 1.3 billion doses next year, requiring a lot of dry ice (carbon dioxide in solid form at around -78 degrees Celsius), and a lot of isothermic boxes. The boxes will hold up to 975 vials (4,875 doses) and can be refilled with dry ice for up to 15 days of storage.

Pfizer is testing the supply chain in four US states. Its CEO, Albert Bourla, said Wednesday he has “zero concerns” about the cold chain requirements.

But shipping such a vaccine can pose big challenges. Dr. Jarbas Barbosa, assistant director of the Pan American Health Organization, told CNN that “the rural and the urban areas in any country in the world are not ready to manage this vaccine today.”

“So, who is prepared in the world? No one.”

One issue is the availability of dry ice.

The Compressed Gas Association says carbon dioxide production capacity in the US and Canada is about 30,000 tons a day and is confident its members can meet demand for dry ice. It says that vaccine supply-chain officials be