Switzerland is home to one of the world's largest drug factories, a sprawling production site in the Rhone Valley town of Visp. Owned and operated by contract manufacturer Lonza, the Visp plant is one of several set to produce an experimental coronavirus vaccine being developed by Cambridge, Massachusetts-based Moderna.

Moderna's vaccine is among the most advanced globally, having already progressed to mid-stage clinical testing. Lonza's help will be critical in ensuring sufficient doses are made.

The company's location in Switzerland, with a population of 8.5 million people, could offer another advantage, should limited supply lead to competition between national governments.

"It's a tiny country in terms of population," said Moderna CEO Stéphane Bancel in a recent virtual meeting hosted by the drug industry trade group BIO. "If you make five or six hundred million doses in Switzerland, there's a very small probability that they're going to keep all of that for the Swiss people."

The scramble to develop a vaccine that can control the spread of the new coronavirus has produced more than 160 experimental candidates preparing to enter, or already in, human testing. The research is global, taking place in laboratories located in over 20 countries.

But the manufacturing of any vaccine proven safe and effective will take place mostly in wealthier Western countries, along with China and India, raising questions about fair distribution and access. Concentrated capacity could risk countries turn to "vaccine nationalism," protecting their citizens first with vaccine doses made inside their borders, regardless of who financed development.

This could spark a tug-of-war among the wealthiest nations, delaying distribution to vulnerable people in middle- and low-income countries — a fear realized in 2009 during the influenza pandemic. While the U.S. and Europe were hit hardest, Brazil, India, Chile and Mexico are now among the world’s hotspots.

Tension may be heightened further if leading projects backed by hundreds of millions of dollars in government funding fail in testing — a very real possibility as scientists attempt to do in months what normally takes years.

"Every national government would like to get [a] vaccine for them," said Pfizer's CEO Albert Bourla on a May 28 conference call.

"Although there are discussions at the World Health Organization, the reality is that governments will try to exercise all the levers that they have to be among the first to receive [a] vaccine," he added. "Us [drugmakers], I'm afraid, will be caught in the middle."

Largely, the wealthiest nations and biggest pharmaceutical companies have emphasized the need for equitable distribution. But in shortages occur, with tens or hundreds of thousands of people infected in a country, those commitments could be cast aside.

Already skirmishes have broken out over a reported U.S. attempt to buy Germany's vaccine developer CureVac and comments by the CEO of France's Sanofi that the first doses of its vaccine would go to the U.S., a position he hurriedly walked back.

"The U.S. global health security policy says: 'The U.S. will help other countries lift their immunization capabilities because it recognizes that you're only as healthy as the least healthy person in other countries,'" said Katherine Bliss, a former State Department health policy specialist who is a senior fellow at the Center for Strategic and International Studies.

"When you're in heated political discussions that's easy to forget," Bliss said in an interview.

The Trump administration has suggested Americans will be first in line for vaccine doses it's paying to secure, however.

"Let's take care of Americans first," a senior administration official said on a recent conference call with reporters. "To the extent there is a surplus, we have an interest in ensuring folks around the world are vaccinated."

The U.S. has funded vaccine work by Moderna, Johnson & Johnson, Merck & Co., Sanofi and AstraZeneca, the last of which committed to provide the U.S. with 300 million vaccine doses beginning in October.

But the senior administration official denied U.S. deals with drugmakers would exclude other countries from getting a vaccine. "We are in no way inhibiting access around the world," he said.

Collectively, the leading coronavirus developers are promising to make some six billion doses through the end of next year, which, at face value, might sound sufficient.

Testing doesn't always work out, however, and the unprecedented timelines drugmakers have laid out could add new risks. Supplies for those that do won't be available all at once, and few companies have selected the exact dose they expect to work best, complicating manufacturing projections.

Non-governmental groups organizing the international pandemic response acknowledge the danger nationalistic attitudes could pose.

"It's a risk that we're aware of, but not one that we can solve alone," a spokesperson for the Coalition for Epidemic Preparedness Innovations wrote in an email to BioPharma Dive. "It needs a political solution. One way we intend to mitigate is to scale out manufacturing to sites in multiple jurisdictions."

That's been the approach of AstraZeneca, which signed a deal with CEPI and Gavi the Vaccine Alliance and separately with the Serum Institute of India to build a supply chain to low- and middle-income countries for its vaccine, which was developed by the University of Oxford. Those two deals alone aim to eventually deliver 1.3 billion doses.

Others could follow in outsourcing vaccine manufacturing to local companies. The stage was set by Gilead, which licensed its COVID-19 drug remdesivir to nine generic drugmakers in Egypt, India and Pakistan for distribution to 127 countries.

In addition to that, Bangladesh-based manufacturer Beximco has begun producing a generic version of remdesivir using a patent waiver under World Trade Organization rules — an additional avenue for vaccine production outside the main countries now involved.

CSIS' Bliss pointed to available manufacturing capacity in India, Brazil and South Korea that could help supply lower-income countries through licenses with manufacturers or through patent waivers.

Even if companies and governments can cobble together enough factory floor space to produce a vaccine for the globe, supplies of critical components like glass vials and syringes are likely to be strained, risking a replay of earlier fights over masks and ventilators.

International cooperation will likely be needed to ensure access to vaccines in middle- and lower-income countries.

"Diseases don't stop at borders," Bliss said. "If we have any hope of revitalizing society and the economy, and being able to trade and travel and do the kinds of things that have led to so much international engagement over the last three decades, we're going to have to recognize that it's imperative that vaccines be available worldwide."

Ned Pagliarulo contributed reporting