AstraZeneca has revealed that annual coronavirus vaccinations might be needed due to the unpredictability of COVID-19. The chief executive officer of the pharmaceutical giant warned on Thursday that people might need more than one shot of the coronavirus vaccine in the future to be fully protected from the virus.

The race to develop a safe and effective coronavirus vaccine is still on. On Thursday, however, frontrunner AstraZeneca noted in an interview that if their work proves to be successful, their vaccine might have to be administered every 12 months to ensure immunity from COVID-19.

 “What we know is that most companies are targeting two injections for their initial vaccination and then our own assumption based on what we know from the technology we use with SARS 1 is that the immunity could last 12 months, maybe 18 months,” said AstraZeneca CEO Pascal Soriot. “But the truth is that we don’t know, this virus is very unpredictable,” he added.

The late-stage trials for AstraZeneca’s coronavirus vaccine are being conducted in the U.K., Brazil, and South Africa. Trials will also take place in the U.S. after the trials in the first three countries are completed. The trials will test how the immune system responds to the vaccine.

AstraZeneca is just one of the many companies working on a potential coronavirus vaccine. Earlier this month, its vaccine, which it is developing alongside Oxford University, produced a promising immune response in large, early-stage human trials.  

The British firm has already closed deals to distribute its potential COVID-19 vaccine to different countries in recent months. In June, AstraZeneca closed a deal with the Inclusive Vaccines Alliance in Europe. Under the agreement, the company would supply up to 400 million doses of its vaccine to Germany, France, Italy, and the Netherlands if its late-stage trials turn out successful. The firm will also produce 2 billion shots for low and middle-income countries in the coming months.

“We have set up supply chains independently from each other,” said Soriot. “If it does work, we will be able to start supplying the vaccine in October, November and our goal is to supply everyone around the world at the same time,” he added.

Coronavirus COVID-19 Laboratory Test, Cure, Vaccine Andressa Parreiras, Biomedic, and Larissa Vuitika, biologist, work in a laboratory during the extraction of the virus genetic material on March 24, 2020 in Belo Horizonte, Brazil. The Ministry of Health convened The Technological Vaccine Center of the Federal University of Minas Gerais laboratory to conduct research on the coronavirus (COVID-19) in order to diagnose, test and develop a vaccine. According to the Ministry of Health, as of Tuesday, March 24, Brazil has 1.891 confirmed cases of the coronavirus (COVID-19) and at least 34 recorded deceases. Pedro Vilela/Getty Images