The following article originally appeared in FiercePharma and was written by Fraiser Kansteiner

Pfizer on Monday revealed stellar early results from its phase 3 COVID-19 vaccine trial, but the news was quickly met with concerns about access as the vaccine comes with hefty cold chain requirements. Pfizer, for its part, already has its sights set on a next-generation formula that could help resolve those storage concerns, the drugmaker’s top scientist said.

The drugmaker is weighing several options for an improved vaccine that could be ready as early as 2021. “For the COVID-19 disease, I think we’ll roll out next year a vaccine in powder format,” Pfizer’s chief scientist, Mikael Dolsten, told Business Insider Monday.

While Dolsten didn’t specify the storage temperature requirements for a powder-form vaccine, the second-generation version “could be just for refrigeration,” providing at least “one simplification” over the drugmaker’s current version. The first-generation form must be stored frozen at negative 94 degrees Fahrenheit, executives have said.

In its quest to deploy 100 million doses of its vaccine globally by year-end, Pfizer has outlined its own distribution effort focused on sites in Michigan and Belgium, which leverages GPS-monitored shipping containers able to keep shots at the required temperature for 10 days. The company has also queued up additional storage sites in Wisconsin and Germany.

But the costs and logistics of such a plan add up fast and vaccine experts have warned that storage requirements for Pfizer’s shot could hinder access in all but the wealthiest of nations. Given the novel mRNA platform behind Pfizer’s shot, many countries will face the question of whether to establish previously unneeded deep-freeze production and transportation networks or wait for a vaccine based on an established technology. Other vaccines, such as those from Novavax and Johnson & Johnson, could utilize existing infrastructure.

“[The shot’s] production is costly, its component is unstable, it also requires cold-chain transportation and has a short shelf life,” director of the Beijing-based Global Health Drug Discovery Institute, Ding Sheng, told BNN Bloomberg.

In China, Shanghai Fosun has teamed up with the state-owned Sinopharm to ship Pfizer’s shot in cold storage trucks to vaccination sites around the country, where the shots will need to be used within five days, lest they spoil. The effort is likely to cost Fosun tens of millions of yuan, or millions of dollars, according to the company’s chairman Wu Yifang. Even then, the odds are high that cold storage requirements will lead to a large portion of those vaccines going to waste, Michael Kinch, a vaccine specialist at Washington University in St. Louis, said.

This has led some, including Ding at the Global Health Drug Discovery Institute, to question the benefit of overhauling storage infrastructure with a number of other vaccine candidates seemingly around the corner.

“If there is a protein-based vaccine that could achieve the same effect as an mRNA vaccine does and there’s the need to vaccinate billions of people every year, I’d go for the protein-based shots in the long run.”

Meanwhile, developing nations like India are split on how, or whether it’s even possible, to fulfill the Pfizer vaccine’s frigid shipping requirements.

The country’s current cold chains struggle to keep up with certain regions’ need for measles vaccines, which are only required for those below the age of three—”a really trivial number of people compared to the numbers that will need a COVID-19 vaccine,” T. Sundararaman, a global coordinator of the public health organization, The People’s Health Movement, told BNN.

Elsewhere, secretary at the country’s health ministry, Rajesh Bhushan, said India was in talks with all vaccine developers about potentially securing doses and added that the nation could boost its current cold-chain capacity if need be.