Pfizer is focusing on building out an inventory of existing products to concentrate on vaccine production in 2021, the firm says.

Pfizer and BioNTech’s mRNA-based COVID-19 vaccine was approved by the European Commission on 21 December, joining previous approvals in the US and the UK, as the partners prepare their commercial manufacturing capacity.

Pfizer reduced estimates regarding the number of vaccines it would be able to produce in 2020 from 100 million to 50 million in November.

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For 2021, the company plans to manufacture up to 1.3 billion vaccines, a demand that a Pfizer spokesperson told Bioprocess Insider would place “significant demands” on its manufacturing network.

In order to reach this capacity, the spokesperson stated that Pfizer would “build inventory of existing products now to allow for COVID-19 vaccine production later,” while the company would also look to utilise its ‘strategic relationships’ to build out its US and European supply chains.

At present, Pfizer has three sites in the US (Saint Louis, Andover, and Kalamazoo) and one site in Europe (Puurs, Belgium) dedicated to the production of the vaccine, alongside BioNTech providing drug substance supply from its own facilities in Germany.

Immediate challenges

When asked about the process of readying the vaccine for global rollout, the spokesperson outlined that distributing the vaccine meant “developing a novel ultra-low temperature end-to-end supply chain for high volumes to a global footprint when we don’t yet know exactly where we will be shipping the vaccine and the storage capabilities at those POU [point of use] locations within each market.”

The low temperature required by the vaccine has also already seen issues with certain batches recording temperatures that were too low when shipped.

When asked about the specific challenges of the low temperature requirement, the spokesperson stated that this had led the company to develop its own 10-day ultra-low thermal shipping unit, as well as the GPS-enable thermal sensors that are connected to a control tower for in-transit real-time inventory visibility and management.

In regard to the GPS tracking, the spokesperson said that these will be monitored 24 hours per day, seven days a week to ‘prevent unwanted deviations’.

Once the vaccines are delivered to the POU, the vaccines can kept in ultra-low-temperature freezers to maintain a shelf life of up to six months; Pfizer’s shippers can be used as temporary storage units for up to 30 days; or the vaccines can be held in refrigeration units at 2-8C for five days.

Moderna received emergency use approval in the US for its rival mRNA vaccine on 18 December, with its vaccine only requiring temperature of -20C refrigeration for six months making it a simpler proposition, in terms of infrastructure.