In Russia's push to develop a vaccine for the novel coronavirus, researchers have tested formulas on themselves, members of the military have been selected for trials and some officials are claiming that a breakthrough could be just months away.

But Russia’s rush to be first — and claim the global bragging rights for President Vladimir Putin’s government — is prompting some in the country to raise warnings about possibly cutting corners with testing and keeping expectations in check.

“There are still too many questions to give you time predictions,” Anna Popova, the head of Russia’s consumer health regulator, said while speaking on a panel Thursday.

“We all want it now, but I know we won’t get it by tomorrow,” she said at an event held by the Valdai Discussion Club, a Moscow-based think tank. “We all want to get there as quickly as possible without violating the ethical rules.”

The contrasting approaches offer a sense of the internal tensions in Russia as the state-backed medical system is throwing resources at potential vaccines. That has led to highly unorthodox proposals that critics say cross ethical lines — such as researchers taking self-administered doses of test samples and a politician’s suggestion of using inmates in clinical trials.

“When we mention some timelines, this is always somebody’s hope,” Popova said. “We can say when it’s technically going to be possible to get the vaccine, but we cannot say in advance how efficient that vaccine is going to be.”

Russia, which has the third-highest number of confirmed coronavirus cases in the world — more than 400,000 — is far from alone in the vaccine hunt. It is competing against other countries, including those with the world’s two biggest economies, the United States and China, in the race for the prestige of having the first team to crack the coronavirus code. Testing is underway on at least five experimental vaccines in China and four in the United States.

Top infectious-disease scientists, including Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, have offered a timeline of a year to 18 months for a vaccine.

But Moscow Mayor Sergei Sobyanin said Thursday that Muscovites will be required to wear face masks until a vaccine is available and that he expects that “will happen between October and February of next year.”

“I would like to hope that we will receive the first large vaccine shipments in October,” Sobyanin told the state-run Tass news agency.

Russian Health Minister Mikhail Murashko was more optimistic just two weeks ago, telling state television that a “vaccine’s availability for broader use should materialize somewhere in late July.” He made the same claim during a parliamentary session.

Deputy Prime Minister Tatyana Golikova said last month that Russia is developing 47 coronavirus vaccines, but that 10 are listed on the World Health Organization’s latest registry.

“I think it’s impossible, if we’re talking about a tested, reliable vaccine ready for mass application,” said Vitaly Zverev of Moscow’s Mechnikov Research Institute of Vaccines and Sera. “We should always remember that we’re going to administer a vaccine to perfectly healthy people. That’s why we have to be absolutely sure it’s safe, but it’s impossible to check that in such a short period of time.”

Zverev said the rush to claim the world’s first vaccine for the novel coronavirus could be about “prestige” for Russia, which has long prided itself on its legacy of scientific innovation. The Soviet Union was a vaccinating force, collaborating with U.S. scientists on a polio vaccine during the Cold War and donating more smallpox vaccines to the World Health Organization than all other countries combined.

But Anton Gopka, the head of the health-care investment firm ATEM Capital, said Russia’s disregard for international ethical protocols means that any vaccine is unlikely to gain acceptance outside of the country.

The Defense Ministry announced Tuesday that it has “finished selecting volunteers” from its military ranks — 45 men and five women who underwent a preliminary health checkup and testing and have not been found to have any diseases for a month, the statement said.

Gopka said that using members of the military means “you can’t say they are volunteers.”

“We have brilliant scientists, but there needs to be a constructive discussion about bioethical standards,” he said.

Researchers at Moscow’s Gamaleya Research Institute, part of the Russian Health Ministry, drew scrutiny after boasting about testing a vaccine on themselves — an act Gopka referred to as “crazy” and Zverev similarly decried because it means the experiment couldn’t have been blind, meaning the subject doesn’t know whether he or she received a placebo or the vaccine.

Gamalyea’s director, Alexander Gintsburg, told the Interfax news agency that the staff working on what is called the viral vector vaccine “didn’t so much seek to test it on themselves, rather, they sought to protect themselves in order to be able to work on this development amid the pandemic.”

Gopka said that he doubts that there was any ill intent with the methodology but that the mentality needs to change for wider acceptance of any results.

“They’re trying to show the commitment of the state, or that by testing it on themselves, they’ll reassure people it’s safe,” Gopka said.

Other vaccine fervor has included research from St. Petersburg’s Institute of Experimental Medicine on a vaccine that could be administered orally in a dairy product, perhaps yogurt. Nationalist lawmaker Vladimir Zhirinovsky made headlines last month when, in an interview with state television, he proposed asking inmates to volunteer for trials in exchange for reduced prison sentences.

“This rush scares me,” Zverev said. “I believe the earliest we can have a vaccine ready is the middle of next year.”