To save manufacturing space for its growing vaccines plans, Pfizer has said it will outsource production of some of its pharmaceutical portfolio. The work is planned to be shared out with a network of 200 contractors in the US and Europe.

The partners include major international players such as Lonza, Catalent and Thermo Fisher Scientific, Pfizer's head of global supply, Mike McDermott, told the Reuters news agency. The drugmaker didn't specify which of its contractors would be tapped in the effort.

Pfizer is also looking toward building up inventory for its drugs before starting manufacture of the potential vaccine launches at scale.

The US market’s largest player has designated three US sites and one in Belgium for the production of its Covid-19 mRNA vaccine candidate, if clinical trials are successful and regulatory approval is assured.

Pfizer is pursuing development of a vaccine in collaboration with German biotech BioNTech. The companies are now beginning human trials testing with four candidates, for which the German partner will supply doses. Earlier, Pfizer said “millions of doses” could be reader by the end of 2020, hundreds of millions in 2021.

The drugs giant’s US vaccine manufacturing sites in Kalamazoo, Michigan, and Andover, Massachusetts, as well as St. Louis, Missouri, are being eyed for the early stages of the vaccine ramp-up. Raw material manufacturing would be concentrated in St. Louis and drug substance manufacturing in Andover. Kalamazoo would handle formulation and filling.

So far, Puurs, Belgium, is the only one of Pfizer’s European manufacturing center in focus for vaccine production, but the company is said to be looking at others. BioNTech intends to add capacity at two of its facilities in Germany.