The Russian developers of a coronavirus vaccine have developed immunity to the infection after self-administering it, Interfax reported Friday.

Scientists at the Gamalei Research Center for Epidemiology and Microbiology “aren’t so much testing as protecting themselves to continue working,” its head Alexander Ginzburg told the news agency.

“Everyone’s alive, healthy and happy,” Ginzburg said when asked if the vaccine developers experienced any side effects. “As such, everyone involved in development is protected.”

Ginzburg did not say how many people took the vaccine, which uses a weakened virus to deliver small parts of a pathogen and stimulate an immune response. He identified the test subjects only as a “wide range” of developers, preclinical researchers and technologists.

The research center is awaiting the results of monkey trials in order to seek permission from the Health Ministry to begin clinical trials on humans, Ginzburg said.

Russia’s health minister said last week that a Covid-19 vaccine would be available as soon as late July. U.S. officials hope to develop one by the first half of 2021.

Russia is currently developing 47 coronavirus vaccines. World Health Organization data estimates that more than 100 draft vaccines were in development worldwide as of late April.

With 326,448 reported infections, Russia has the world’s second-highest number of coronavirus cases behind the United States.