That deadline lands right in the middle of the estimated completion dates of other COVID-19 vaccine frontrunners, wrapping up months before Moderna’s estimated October 2022 completion date, Pfizer’s December 2022 date, and Johnson & Johnson’s estimated March 2023 end date, and after the estimated October 2021 phase III trial end dates for the Sinovac and the AstraZeneca-Oxford University vaccines.

There are currently over 100 COVID-19 vaccine candidates in development across the world. Some vaccines have received emergency authorization or are seeking it, which could see vaccines administered before trials officially end. The U.S. could distribute Moderna and Pfizer vaccines, for instance, as soon as late 2020 or early 2021.

For Yu Xuefeng, cofounder, chairman, and CEO of CanSino Biologics, the longer timeline is worth it. CanSino’s vaccine is the only frontrunner that comes in a single dose, instead of the two-dose regimen that other COVID-19 vaccines will require for a strong immune response.

Given the urgent need for mass distribution of a COVID-19 vaccine, there are huge benefits to a safe and effective dose that can be delivered in one sitting instead of two, Yu said at the Fortune Global Forum on Tuesday.

“In the pandemic environment, what you need is a vaccine that can quickly provide protection…If we can make a single dose work, it will stop the spread of the virus, and it will certainly have a good control of the pandemic situation,” Yu said.

CanSino’s Ad5-nCoV vaccine is backed by the Chinese military and is currently undergoing late-stage trials in Pakistan, Russia, and other countries, including Mexico, which said earlier this month it would purchase 35 million CanSino vaccine doses for its citizens.

The vaccine, which received Chinese government clearance for military use in June, uses a human adenovirus vector, which Yu said is “one of the safest” vaccine vectors. CanSino used the same vector to create its Ebola virus vaccine, which is split into two doses.

Data from the Ebola vaccine shows that a second dose can boost the effectiveness of the Ad5 vaccine, Yu says, so CanSino eventually may offer a second dose of the COVID-19 vaccine for people with weaker immune systems.

CanSino hasn’t decided on a price for its COVID-19 vaccine yet.

“The price is less a concern for now,” Yu said. “We have to make it first.”

This article has been updated to clarify the estimated timelines for vaccine developers’ phase III clinical trials.