LONDON — Drugmakers and research centers are scrambling to deliver a safe and effective vaccine to help bring an end to the coronavirus pandemic that has claimed over 1.3 million lives worldwide.

Two Covid-19 vaccines have been found to be highly effective in late-stage trials in recent days, boosting optimism at a time when health systems in Europe and the U.S. are once again being pushed to breaking point.

Huge challenges remain before a vaccine can be rolled out, however. The global battle to secure prospective supplies has raised alarm about equitable access, while questions remain over logistics, distribution, and, perhaps most significantly, cost.

International aid group Medecins Sans Frontieres (Doctors Without Borders), for example, has expressed concern about pharmaceutical companies holding the power to decide who gets access to a vaccine, when, and at what price.

CNBC takes a look at some of the leading coronavirus vaccine candidates.

Moderna

A researcher works in a lab run by Moderna Inc, who said November 16, 2020 that its experimental vaccine was 94.5% effective in preventing COVID-19 based on interim data from a late-stage clinical trial, in an undated still image from video.

Moderna | via Reuters

Pfizer-BioNTech

Pfizer and BioNTech reportedly plan to load suitcase-sized boxes from distribution sites in Kalamazoo, Michigan, and Puurs, Belgium, onto as many as two dozen trucks per day, allowing for the daily transit of roughly 7.6 million doses to nearby airports.

Pfizer on Tuesday launched a pilot delivery program for its experimental vaccine in Rhode Island, Texas, New Mexico, and Tennessee. The plan, Pfizer said, was to try to address distribution challenges regarding its ultra-cold storage requirements.

The companies are reportedly charging $20 per dose for its vaccine, significantly lower than Moderna.

Pfizer and BioNTech have secured agreements with several countries across the globe. The European Union has ordered the most, with 300 million doses confirmed as of Nov. 11, Japan has agreed to procure 120 million, and the U.S. has bought 100 million.

The U.K., Canada, Australia and Chile have all bought at least 10 million doses of the Pfizer-BioNTech vaccine.

AstraZeneca-Oxford

A Brazilian doctor voluntarily receives an injection as part of phase 3 trials of a vaccine developed by the University of Oxford and British pharmaceutical company AstraZeneca, in July 2020.

Nelson Almeida | AFP | Getty Images

Medecins Sans Frontieres highlighted that while AstraZeneca had committed not to profit from the vaccine it is developing with Oxford “during the pandemic,” the firm had given itself the power to charge
higher prices as soon as July next year.

AstraZeneca CEO Pascal Soriot said on Nov. 5 that the firm will “treat the development of the vaccine as a response to a global public health emergency and not a commercial opportunity.”

“We have committed to providing the vaccine on a global basis at no profit for the duration of the pandemic. That means that all existing supply agreements will be conducted on this basis,” Soriot said.

Johnson & Johnson

Johnson & Johnson’s vaccine is a one-dose shot using technology based on the development and production of adenovirus vectors, or gene carriers. Similar technologies were used to develop and manufacture the company’s Ebola vaccine.

A 60,000-person single-shot clinical trial was launched in September, although it has since signed an agreement with the British government for a separate two-dose clinical trial.

J&J has reportedly said that if results of the single-shot trial are positive, it could simplify the distribution of millions of doses, potentially gaining an advantage over some of its leading rivals that require two doses.

J&J’s vaccine requires basic refrigeration for storage and is thought to cost around $10 a dose.

The EU has ordered 200 million doses of the vaccine candidate. Meanwhile, the U.S. has procured orders of 100 million, Canada has agreed to buy 38 million and the U.K. has ordered 30 million.

— CNBC’s Berkeley Lovelace Jr. & Noah Higgins-Dunn contributed to this report.