The world's first single-shot coronavirus vaccine was scheduled to arrive in the Gulf on Monday night.
Bahrain prepared to receive the consignment of Janssen vaccines and was expected to begin using it this week.
The kingdom was among the first nations to approve the vaccine - almost immediately after US authorities gave it the go ahead on Friday.
A local agent for Johnson & Johnson, which owns Belgium-based Janssen Pharmaceutica, and a Bahrain government official both confirmed the anticipated shipment to The National on Monday.
Hospitals were told to expect the vaccines to be available almost immediately and to update their websites and bookings accordingly.
The number of available doses was not known and such figures were rarely released by Gulf governments.
Bahrain was among the global leaders in the race to vaccinate its small population. But it has since faced setbacks as the arrival of supplies of Pfizer-BioNTech slowed to a crawl.
In January, its health ministry said scheduled shipments had failed to arrive on time.
Bahrain also uses China's Sinopharm - the most widely-used vaccine in the UAE.
It has limited supplies of the Indian-made Oxford-AstraZeneca vaccine and Russia's Sputnik V.
Bahrain remained seventh in the world as of February 28, having administered 17 doses per 100 people in the population. Israel and UAE were first and second respectively.
Janssen's single-shot vaccine is designed to protect with a single dose instead of two shots three or four weeks apart.
In the US and seven other countries where trials took place, the single-shot vaccine was 66 per cent effective overall at preventing moderate to severe illness, and much more protective – 85 per cent – against the most serious symptoms.
That meant it is not as strong as some two-shot rivals but still potentially crucial at a time of major vaccine shortages.
A high bar was set by two vaccines such as Pfizer-BioNTech and Moderna, each of which was about 95 per cent effective in preventing symptomatic illness when given in two doses.
Russia's Sputnik V is just over 91 per cent effective and China's Sinopharm is 79 per cent effective.
The J&J-Janssen findings had some geographical variation. The vaccine worked better in the US – 72 per cent effective against moderate to severe infections – compared with 57 per cent in South Africa, where it was up against a more contagious variant of the virus.
UAE latest vaccine roll-out - in pictures
